A low thermal impedance structure in a phased array

Low Thermal Impedance Structures in Phased Arrays

CROSS-REFERENCE TO RELATED APPLICATIONS

35 of U.S. Provisional Application Serial No. 62/272,201, filed December 29, 2015, entitled "A Low Thermal Impedance Structure in a Phased Array," the entire contents of which are incorporated herein by reference in their entirety. Claims under USC 119(e).

FIELD OF THE INVENTION The present invention relates generally to phased arrays such as those used in cellular or wireless local area networks, and more particularly to thermal management of such phased arrays.

Phased arrays generate beamed radiation patterns in free space to allow the formation of selective communication channels. A phased array is formed by arranging a plurality of antennas in a grid pattern on a flat surface, the antennas being typically spaced from each other by one-half the wavelength of a radio frequency (RF) signal. A phased array can produce radiation patterns in a desired direction by adjusting the phase and amplitude of the RF signals being applied to each antenna. The emitted radio RF signals may be enhanced in certain directions and suppressed in other directions by these adjustments. Similarly, phased arrays can be used to enhance reception of wireless RF signals from desirable directions in free space while suppressing wireless RF signals arriving from other directions. The incident RF signals, after being captured by the phased array, have a phase and amplitude adjusted and combined to enhance the received RF signal from the desired region of free space and suppress the received RF signal from the undesired region of free space. The radio beam is electronically steered to transmit and receive communication channels, eliminating the need to mechanically adjust the position or orientation of the antenna.

A phased array requires an orchestration of a plurality of antennas forming the array to perform in unison. A corporate feed network provides timing to the phased array by delivering equal copies of the RF signal to each of a plurality of antennas forming the phased array. A uniform arrangement of a plurality of antennas over a planar area is defined as a phased array having a flat surface area that extends over several wavelengths of the carrier frequency of the RF signal in both the X and Y directions. For example, a phased array with 100 antennas arranged in a square planar area would have an edge dimension equal to 5 wavelengths of the RF carrier frequency in each direction.

Packaged in discrete packages or integrated circuit components, power amplifiers (PA) amplify the transmit signal before the signal is coupled to the antenna. The power amplifier PA is manufactured in a semiconductor chip. The chip is then packaged and mounted on a printed wire board (PWB) in the system. A circuit board for a PA is a PWB comprising one or more metal sheets laminated between electrically non-conductive layers of a laminate. Some metal sheets are patterned to form a wiring interconnection network that electrically connects the terminals of the integrated circuit components and other individual components together, as shown in the corresponding circuit diagram. Other metal sheets may be used as heat spreaders to spread heat laterally along the plane of the circuit board. Integrated circuit components may be packaged and soldered to one of the surfaces of the PWB or mounted to the PWB as a bare die and surface treated and wire bonded or solder bumped to that surface of the PWB.

Phased array power amplifiers are designed to process signals with large peak-to-average power ratios (PAPRs). Such a PA would be designed to perform linearly at the peak power ratio; However, doing so causes the PA to be low power efficient when the signal has an average power ratio. The occurrence of peak power ratios is usually rare; Thus, to ensure that the PA always operates linearly, the PA generates a large radiated heat loss when the signal has an average power ratio. A single PA can generate 25W or more of heat. A phased array with 100 antennas can generate as much as 2500W. For comparison, a PA of a current base station driving a single antenna only dissipates 100 watts of power.

The antenna and electrical components of the phased array are placed in an enclosed environment to protect the antennas from weather conditions such as rain, snow, and the like. However, the enclosed environment used to protect the antenna and electrical components also prevents the removal of heat generated from the PWB in which the antenna is mounted. This can cause problems due to overheating of the phased array system.

Generally, in one aspect, the present invention features an antenna system comprising: an antenna module, the antenna module comprising: a thermally conductive base plate having a front surface and a rear surface; a plurality of thermally conductive standoffs; an antenna element extending from a front surface of the base plate; a circuit board having a front surface and a rear surface and comprising a ground plane on a rear surface of the circuit board, the ground plane of the circuit board being in adjacent thermal contact with the rear surface of the base plate; a plurality of electrical components mounted on the circuit board, the plurality of electrical components including an I/O connector; and a power amplifier in thermal contact with the baseplate, wherein the power amplifier drives the antenna element with a transmit signal. The antenna system comprises: a thermally conductive support plate having a front surface and a rear surface, the front surface of the support plate being separate, parallel, and facing the front surface of the base plate, the circuit board being positioned between the base plate and the support plate Ham - ; and an I/O connector on a circuit board coupled to the I/O connector to electrically connect the circuit board to the master board, wherein the master board is disposed between the front surface of the circuit board and the support plate. positioned, the master board comprising signal paths for routing signals to the circuit board, and wherein the plurality of thermally conductive standoffs thermally connect the base plate to the support plate.

Other embodiments include one or more of the following features. The power amplifier is mounted directly on the base plate or alternatively directly on the circuit board. The base plate and the support plate are made of metal. The antenna system includes a heat sink assembly thermally coupled to the support plate, the heat sink assembly including a plurality of metal fins for convectively dissipating heat generated by the circuit board. . The master board has a plurality of holes through which the plurality of standoffs pass to thermally connect the base plate to the support plate. The antenna system further includes a heat-conducting material sandwiched between a back surface of the circuit board and a back surface of the base plate. The thermally conductive material is a thermally conductive gasket. The signal paths on the master board are for routing IF and local oscillator signals to the circuit board. The antenna system includes an RF transparent radome that covers and protects the antenna module and the master board. The master board contains only passive electrical components. The master board is mounted on the support plate. The circuit board and the master board are printed wiring boards.

Generally, in another aspect, the present invention provides: a plurality of antenna modules; thermally conductive support plate; and a master board on said support plate, said master board comprising signal paths for routing signals to said plurality of antenna modules and comprising a plurality of I/O connectors, wherein said plurality of of the antenna modules are electrically connected to the master board, and each antenna module of the plurality of antenna modules includes: a thermally conductive base plate having a front surface and a rear surface; a plurality of thermally conductive standoffs; an antenna element extending from a front surface of the base plate; a circuit board having a front surface and a rear surface and comprising a ground plane on a rear surface of the circuit board, the ground plane of the circuit board being in adjacent thermal contact with the rear surface of the base plate; a plurality of electrical components mounted on the circuit board, the plurality of electrical components engaging a corresponding I/O connector of a plurality of I/O connectors on the master board to electrically connect the circuit board to the master board Includes I/O connectors for - ; and a power amplifier in thermal contact with the base plate, wherein the power amplifier drives the antenna element with a transmit signal. The plurality of thermally conductive standoffs thermally connect the base plate of the antenna module to the support plate.

1 is a perspective view of two instances of a cross pole antenna; Figure 2 shows a cross pole antenna oriented across a Module Ground Plane with doglegs. 3 shows a heat conducting gasket positioned below the module ground plane. Figure 4 shows the module circuit board positioned under the heat conduction gasket. 5 shows the module circuit board and the heat conduction gasket connected together. 6 shows a cross pole antenna connected to the module ground plane. 7 is a cross pole antenna; module ground plane; heat conduction gasket; and a module circuit board showing four components connected together to form a module. FIG. 8 shows a cross-sectional view taken along a vertical plane including A-A' of FIG. 7 . 9 shows two instances of a module. 10 shows two module instances coupled together. 11 presents a perspective view of the module and the master board. 12 shows a perspective view of the modules, the master board and the module metal support. 13 shows the master board connected to the module metal support. 14 shows the modules connected to the module metal support; FIG. 15 shows a cross-sectional view taken along a vertical plane including B-B of FIG. 14 . 16 shows a top view of a phased array. FIG. 17 shows an enlarged view of area 16-1 of FIG. 16 . FIG. 18 shows an enlarged view of area 16-2 of FIG. 16 . 19 shows a top view of the phased array with a radome sealing part of the phased array and convective heat flow from the exposed fins. FIG. 20 shows an enlarged view of region 19-1 of FIG. 19 with volume A containing RF shielded components. 21 shows a top view of a phased array with a larger volume AB and convective heat flow from the exposed fins. 22 shows an enlarged view of region 21-1 of FIG. 21 with volume AB containing RF shielded components. 23 shows a cross-sectional view along the vertical plane including C-C' of FIG. 21 showing thermal rails; 24 shows cross pole antennas; module ground plane; heat conduction gasket; and a module without module standoffs comprising four components, wherein the module circuit boards are connected together to form a module. FIG. 25 shows a cross-sectional view of FIG. 24 . 26 shows two instances of a module without module standoffs. 27 shows two instances of modules without module standoffs coupled together. 28 shows a perspective view of the module without module standoffs and a master board. 29 shows a perspective view of the module without module standoffs, master board and heat transfer bars. 30 shows a perspective view of the module without a base plate with module standoffs, master board, heat transfer bar and heat fins. 31 shows the module without the module standoffs, the master board, the heat transfer bar and the base plate connected together with the heat fins. 32 shows a top view of a phased array. FIG. 33 shows an enlarged view of area 32-1 of FIG. 32 . 34A shows a rear view of a phased array illustrating vertical fins. 34B shows a rear view of a phased array illustrating fins installed at an angle to provide improved heat transfer to an ambient environment. 35 shows a bottom view in the middle of a phased array with a divided master board connected to a distribution board. Figure 36 shows a bottom view in the middle of a phased array of another embodiment in which partitioned master boards are connected to a distribution board.

1 illustrates a perspective view of two cross pole antennas 1-1. Each cross pole antenna includes two dipole antennas orthogonal to each other. For example, the dipole antenna on segment 1-2 is orthogonal to the dipole antenna on segment 1-7. Half of the dipole antennas 1-4 are illustrated in segments 1-2. The dipole antenna on segment 1-7 is not visible from this view because the dipole is on the back of 1-7. The right cross pole antenna includes segments 1-8 and 1-9 that are orthogonal to each other. The dipole is seen in segments 1-8 as "C" shaped patterns 1-6 and 1-10. An antenna lead 1-5 located at the lower intersection of segments 1-8 and 1-9 drives the cross pole antenna. A similar antenna lead is placed in a similar position relative to the left cross pole antenna. Mounting brackets 1-3 are used to mount the cross pole antenna to the surface of the ground plane. The front view shows the dipole antennas 1-6 and 1-10, made of metal layers patterned on the surface of the circuit board for the antenna segments 1-8. It should be understood that any suitable antenna, dipole, patch, microstrip, or the like, currently known or developed in the future, that functions to transmit or receive RF signals may be used with such an antenna.

2 is a perspective view of a module metal plate 2-1 for cross-pole antennas. The module metal plate has at least one module standoff (2-2) and a corresponding module foot (2-5). The module standoffs and module feet form a dogleg. The module foot has a set of holes (2-3) used for mounting purposes. The module metal plate includes holes 2-4 for electrical leads that connect the front end circuitry to the antenna leads. Holes 2-4 are aligned with the input node of one of the dipole antennas of the cross pole antenna corresponding to the antenna on segment 1-8. Holes for orthogonal dipole antennas of cross pole antennas corresponding to antennas on segments 1-9 are not illustrated in order to simplify the drawing. Similarly, the "hole for the antenna lead" is aligned with the input node of one of the dipole antennas of the cross pole antenna corresponding to the antenna on segment 1-7. The holes for the orthogonal dipole antenna of this cross pole antenna corresponding to the antenna on the segment 1-2 are not illustrated in order to simplify the drawing. A hole is typically associated with each of the antennas. A plurality of antennas requires a plurality of holes corresponding to the module metal plate.

The modular metal plate is aluminum with a thickness of about 3.1 mm, although other metals are alternatively suitable. Examples of metals having high thermal conductivity include, but are not limited to, copper, silver, zinc, nickel, iron, and the like. In addition, metal alloys can also be used in the construction of the system. The dogleg may be formed by sequentially bending metal tips of the module metal plate. A first bend creates a standoff portion, and a second bend at the tip of the standoff portion forms a foot. The dogleg structure of the standoff and foot is also a separate metal forming the dogleg, which is attached to the module metal plate by a combination of screws, fastener means such as nuts and bolts, conductive cement, etc. It can also be implemented as a component.

3 shows a perspective view of a thermally conductive gasket 3-1 for a module metal plate. The surface of the gasket has holes 2-4 in the module metal plate and two holes 3-2 aligned with the antenna leads 1-5 of the cross pole antennas. In some embodiments, the gasket may be replaced with a paste, adhesive or metal adhesive or the like, or connected by fasteners (screws, bolts, etc.) to hold the two parts together. The gasket may have electrical properties that are conductive or insulating. A gasket is also optional.

Fig. 4 shows a perspective view of the module circuit board 4-1 with regard to the gasket, the module metal plate and the cross pole antenna. The module circuit board 4-1 is a multilayer PWB board having integrated circuits, other discrete components, and an I/O connector 4-2 mounted thereon. At least one power amplifier (PA) used to drive the cross pole antenna is mounted on the module circuit board. The output leads of the PA can be accessed from the module circuit board in position 4-3. The access point of the PA 4-3 is aligned with the hole 3-2, the hole 2-4 and the antenna lead 1-5. A multilayer PWB board, having at least one sheet of metal on and possibly within the PWB, serves at least two purposes: first, a ground plane extending over the area of the PWB and second, to electrical components mounted on the PWB. A heat spreader that laterally transfers heat generated by

5 illustrates the bottom surface of the gasket 3-1 on the top surface of the circuit board 4-1. 6 illustrates the attachment of a cross pole antenna 1-1 to a module metal plate 2-1 showing four dipole antennas attached to the module metal plate 2-1. However, other implementations are not limited to this particular configuration or number of antennas. Various embodiments include at least one antenna attached to a module metal plate. Any two antennas may be arranged orthogonal to each other, parallel to, or in any direction. Mounting brackets 1-3 connect the antennas to the module metal plate with attachments. Note the alignment of the antenna leads 1-5 with the holes 2-4 of the module metal plate 2-1 and the holes 3-2 of the gasket aligned. Other embodiments may remove the gasket altogether. Alternatively, the ground plane metal of the PWB can be directly contacted to the module metal plate contacts using fasteners (screws, bolts, etc.) to hold the two parts together, or using paste, adhesive or metallic adhesive, etc. .

7 shows the complete module 7-1 after attaching the upper surface of the gasket to the lower surface of the module metal plate. The gasket may electrically insulate the module circuit board from the module metal plate. However, the gasket has a high thermal coefficient and effectively transfers the heat generated by the circuit components on the circuit (particularly the PA) to the module metal plate. After assembly the module includes two cross pole antennas, at least one module standoff and module foot, and at least one I/O connector. The module 7-1 is used as a building block constituting the phased array. 7 illustrates an example of a module for a phased array. For other types of module design and information on assembly, electrical and structural characteristics of the module and other components of the module phased array, the entire contents of which are incorporated herein by reference and filed on July 22, 2015 , see U.S. Provisional Application No. 62/195,456, entitled "Phased Array." A view 7-2 along the vertical plane comprising A-A' is shown in FIG. 8 .

Figure 8 shows a cross-sectional side view 7-2 of the module in a vertical plane comprising A-A'. A right cross pole antenna comprising segments 1-8 and 1-9 is aligned at the intersection of the segments above aperture 8-1. The finished hole (8-1) is connected to the hole (2-4) of the module metal plate (2-1), the hole (3-2) of the gasket (3-1), and the output lead (4-3) of the PA. Consists of the alignment of the holes of the corresponding module circuit board (4-1). The hole 8-1 creates an opening between the antenna lead located on one side of the module metal plate and the output lead of the PA mounted on the PWB located on the other side of the module metal plate. Surrounded by an insulating dielectric cover or simply bare, metal interconnects 8-2 are used to connect the output leads of the PA to the input leads of the antenna. The wires and holes are sized appropriately to create a coaxial electrical interconnect characterized by an impedance of about 50 ohms. In one embodiment, a metal interconnect is soldered to the leads on the top surface of the PWB, and the other end of the metal interconnect is soldered to the leads of the antenna. Other methods of connecting metal interconnects at one or both ends are suitable and available as alternative embodiments. Examples are crimp-on connectors, plug and socket connectors, blade connectors, and the like.

Some or all of the electrical components associated with the PWB in the phased array are shielded using an RF shield. The electrical system of the phased array (antenna, PA output leads) generates a large amount of electromagnetic radiation that can be picked up by nearby electrical components. The RF shield is a metal cover located near these electronic components to isolate them from electromagnetic radiation that strays from them. RF shielding attempts to create an enclosed environment for electrical components. RF shielding blocks electromagnetic radiation from interfering with the normal operation of these enclosed electrical components.

The left cross pole antenna comprising segments 1-7 and 1-2 is electrically coupled to the module circuit board 4-1 in a similar manner. The module circuit board 4-1 has an exposed copper layer in contact with the gasket 3-1. On the opposite side of the circuit board, the surface is filled with at least one PA 8 - 3 , an integrated circuit 8 - 4 , discrete components, and at least one I/O connector (not shown). The gasket is a flexible material and helps to compensate for any non-uniform height variations on the manufactured PWB ground plane side caused by manufacturing steps due to through holes or the like. Other embodiments may remove the gasket altogether. Instead, the ground plane metal of the PWB is in direct contact with the module metal plate using fasteners (screws, bolts, etc.) to hold the two parts together, or paste, adhesive or metal adhesive, etc. .

In another embodiment, the PA is directly attached to the module metal plate 2-1 (not shown). In one embodiment, the PWB has an opening into which the PA's integrated circuit can be inserted and attached directly to the module metal plate. The heat generated by the PA will conduct heat through the integrated circuit to the module metal plate. The PA's integrated circuit is bonded to the module metal plate using a thermally conductive adhesive or paste. Wire bonds or tab attachments couple the electrical signals between the PWB and the input/output pads of the PA. The output terminal of the PA is connected to the antenna through the hole 8-1.

9 shows a perspective view showing two modules 7-1 side by side. 10 illustrates the arrangement of two modules 7-1 together to form a component module 10-1. 11 illustrates a perspective view of the component module 10-1 with respect to the master board 11-1. The master board routes intermediate frequency (IF) and local oscillator (LO) signals to a plurality of component modules (and in this particular embodiment passive electrical components and no active electrical components) includes only). At a higher volume, the master board distributes through these connectors at least one LO signals and IF signals from at least one source location on the master board to all modules, and connects at least one input IF signals received from the modules to a connector. It divides into at least one sink location of the master board through the two channels, and uses a corporate feed network or a bidirectional signaling (BDS) network for a distribution network. Because the BDS network is a serial link distribution, it reduces the overall transmission line length and signal loss between the source and destination when compared to a common feed network. For a description of the BDS network, see US Patent Application No. 2014/0037034 entitled "Method and System for Multi-point Signal Generation with Phase Synchronized Local carriers" published on February 6, 2014, and these documents is incorporated herein by reference in its entirety.

The master board is a PWB with exposed metal covering its backside. The I/O connector 4-2 of the component module is aligned with mating interfaces 11-2 located on the master board 11-1. The mating interface 11-2 is a male connector, and the I/O connector 4-2 is a female connector, but the positions of these male/female connectors can be exchanged. When the I/O connector mates with the mating interface of the master board, the module circuit board can use the IF/LO network distributed on the master board. The master board 11-1 also has cutout openings 11-3 aligned with the module standoff and module foot of the modules forming the component module 10-1, some of which is currently hidden from view. These cutout openings allow the module standoffs and module feet to pass through the master board unobstructed. The cutout opening allows the master board to be manufactured as a single circuit board instead of being manufactured as at least two or more circuit boards. A master board manufactured as a single circuit board maintains uniform electrical characteristics experienced by all IF and LO signals propagating to or from all modules of the phased array. Subdividing the master board into two or more circuit boards increases the possible inconsistency in the electrical properties of the electrical traces provided to the propagating IF and LO signals. Mismatches in electrical characteristics between circuit boards can affect an important parameter known as "Synchronization Flight Time", which is undesirable. For a discussion of synchronized flight times, reference may be made to U.S. Patent Application No. 20/0142280, entitled "Low Cost, Active Antenna Arrays," published June 7, 2012, the entire contents of which are incorporated herein by reference. is cited as

12 shows a perspective view of the module metal support 12-1 for the master board 11-1 and the component module 10-1. If desired, the module metal support has a fold that provides additional strength to the structure of the module metal support. 13 illustrates the master board 11-1 secured to the module metal support 12-1. In FIG. 14 , the component module 10 - 1 is attached to the module metal support 12 - 1 . The module standoff (2-2) is designed to have a vertical length from the module metal plate so that a cavity formed between the module metal plate (2-1) and the module metal support part (12-1) is the master board (11-1). ) and allows the I/O connector (4-2) of each module to be inserted into the mating interface (11-2) of the master board. The module feet 2-5 of the modules contact the metal surface of the module metal support. The cutout openings 11-3 allow the module foot (not shown) to pass through the master board 11-1 and directly contact the module metal support 12-1 for efficient heat transfer between the foot and the support. Each module foot is attached to the module metal support by fasteners disposed in holes 2-3 in the module foot. These fasteners may be screws, nuts and bolts, quick release latches, and the like. The fasteners attaching the module metal support to the module foot ensure that both thermal and electrical connections occur between these two components. The thermal connection transfers the heat generated by the electrical components in the module to the module metal support 12 - 1 . The electrical connection ensures that the metal structure of the module and the module metal support are at the same voltage potential. The module metal plate may be coupled to a voltage supply, for example at ground potential, and acts as a ground plane for the antennas. Next, a cross-sectional view along a vertical plane including B-B' is shown.

15 shows a bottom view 14-1 of a plane including B-B'. Four module contours 7-1a, 7-1b, 7-1c, 7-1d are illustrated. Each module has two instances of module feet 2-5. The master board 11-1 provides two cutouts 11-3. The right foot of the module 7-1a and the left foot of the module 7-1b pass through the opening 11-3 of the master board 11-1. The two modules 7-1a and 7-1b form one instance of the component module 10-1. A second instance of the component module 10-1 is formed by the modules 7-1c and 7-1d. The modules are shaped to fit together when placed side by side. Each foot 2-5 includes a hole 2-3 through which each module can be attached to a module metal support 12-1 having a corresponding mating hole. Note that the phased array can be increased in size in the negative Y direction by adding more modules in each row and correspondingly extending the master board. Similarly, if desired, the phased array can be increased in the X direction by adding another row of modules and extending the master board to the right and including additional cutouts in the master board.

16 illustrates a cross-sectional view of an assembled phased array. The antennas are mounted to the module metal plate, and the module standoff and module foot are connected to the module metal support. The module circuit board is connected to the lower side of the module metal plate through a gasket. The master board is connected to the module metal support and illustrates a cutout within the area of the dashed oval 16 - 1 . The cutouts allow each module foot to pass through the plane of the master board and contact the module metal support. The module circuit board is electrically connected to the master board by a connector formed by mating the I/O connector with the mating interface. Row rails 16-3 connect the module metal support to the base plate 16-4. Thermal rails are placed below the module standoffs and corresponding module feet to minimize thermal impedance between these two components. This minimizes the thermal impedance of the heat flowing from the module circuit board to the column rails. The base plate adds additional structural support to the phased array and distributes the heat received from the row rails to the entire base plate. The distributed heat travels laterally and vertically downwards in the base plate. Heat flows to multiple fins 16-5 connected to the underside of the base plate and an external protective shroud that protects the outermost fins. One embodiment of a phased array comprises structural components: a modular metal plate; modular metal supports; thermal rail; base plate; pins; To reduce cost and weight, a protective shroud, aluminum is used as the forming metal, although other metals are suitable. Examples of metals having high thermal conductivity include, but are not limited to, copper, silver, zinc, nickel, iron, and the like. For example, metal alloys may be used in the construction of the system. To sufficiently transport heat, provide structural integrity, minimize cost, and minimize the weight of the phased array, the thickness of the metal component is about 3000 μm. Thicknesses greater than 3000 μm may be used if weight is not an issue, thicknesses less than 3000 μm provide less weight than at increased thermal resistance. Additionally, the type of metal used and the thickness used for each metal component are each independently selected and selected as an alternative embodiment for fabricating a phased array that achieves the desired cost, weight, heat extraction and strength for the unit. can be adjusted. Dashed ellipses 16-1 and dotted ellipses 16-2 identify areas to be enlarged to show these areas in greater detail.

The disclosed structure of the PWB attached to the module metal plate significantly reduces the lateral thermal impedance along the metal sheet within the PWB. A thin layer of copper (typically only 25 microns thick) on the backside of the PWB has limited ability to conduct heat away from the heating electrical component. The modular metal plate itself provides a lateral heat flow path beyond what is available within the copper metal sheet of the PWB. In addition, the modular metal plate can be designed with a thickness significantly greater than 25 microns, providing a much more effective way of moving heat away from the heating components on the PWB. One embodiment of the modular metal plate uses aluminum having a thickness of 3000 microns, which is more than twice as thick as the metal sheets commonly used in PWBs. The lateral thermal impedance of this embodiment can reduce the thermal impedance by an order of magnitude nearly two.

FIG. 17 is FIG. 16 showing heat flow from components mounted on circuit boards (such as integrated circuits, active components and passive components) down through the various structural components to the thermal rail 16-3. The region 16 - 1 of is illustrated in more detail. PAs emit a large amount of heat during normal operation. A single PA can generate more than 25W of heat. A phased array with 100 antennas requiring a PA can produce as much as 2500W. The heat generated by each PA needs to be removed from the phased array to the external environment via a low thermal impedance path. One embodiment for achieving low thermal impedance is described. White arrows indicate the direction of heat flow through the structural components forming the phased array. The thickness of each arrow (when indicating the magnitude of heat flow) may not be drawn to scale. Most of the structural components are made of metal except for the stacked layers of the PWB board. For example, heat flows 17-1 and 17-2 from the surface mounted integrated circuit (IC-1) and the PA may flow through the stacked layers within the circuit board 4-1 before reaching the ground plane of the circuit board 4-1. flows perpendicular to the The gasket 3-1 ensures that the circuit board 4-1 maintains good thermal contact over the entirety of the circuit board's ground plane surface area. The gasket may alternatively be replaced with a paste, adhesive or metal adhesive or the like, or connected by fasteners (screws, bolts, etc.) to hold the circuit board to the module metal plate. Heat flows to the module metal plate 2-1 through the low thermal impedance of the electrically insulating gasket 3-1 (if used).

The stacked layers of PWBs typically provide a high thermal impedance to heat flow. This large thermal impedance can be reduced if the area of the PA package is increased to help dissipate heat over a large area. Moreover, the actual layout of the PA circuit in an integrated circuit can also be redesigned and laid out over a larger surface area of the semiconductor. The heat generated by the power dissipating amplifier stage of the PA will spread over a larger area within the semiconductor, which will further help reduce the thermal impedance of the stacked layers of the PWB between the packaged device and the module metal plate.

Module metal plate 2-1 directs heat flow 17-3 to module standoff 2-2 which transfers heat to module metal support 12-1. Most of the heat captured by the module metal plate is transferred through the module standoff metal component 2-2 to the module metal support as indicated by heat flow 17-6. The integrated circuit packages on the master board transfer their column verticals through the PWB to the module metal support 12-1. For example, the heat flow 17 - 4 of the integrated circuit IC - 2 flows through the circuit board of the master board to the module metal support 12 - 1 . The exposed metal layer on the backside of the master board is in direct thermal contact with the module metal support. A gasket may not be necessary because the heat generated by the master board is much less than that of the module circuit board containing the PAs. The heat flow 17 - 5 from all remaining components of the master board is carried by the module metal support 12 - 1 towards the thermal rail 16 - 3 . The heat flow 17-6 from the module standoffs 2-2 and the heat flow 17-5 from the module metal support are the heat flows 17-7a and 17-7b in the thermal rail 16-3. is combined with Thermal rails 16-3 are positioned below module standoffs 2-2 to minimize thermal impedance between module metal plates 2-1 and thermal rails 16-3. This minimizes the thermal impedance to the heat flowing from the PA.

18 shows in more detail region 16-2 of FIG. 16 showing heat flow from components mounted on the circuit board near the connector. Heat flow is indicated by arrows through the structural components of the module metal plate and the module metal support. The connector 18-1 is used to transfer signals between the module circuit board and the master board. Connectors typically have high thermal impedance and are not efficient thermal conductors. White arrows indicate the direction of heat flow from the module circuit board and master board PWB through the structural components. Most of the structural components are made of metal except for the laminated layers of the PWB board. For example, heat flow 18-2 from integrated circuit IC-3 flows perpendicular to the stacked layers within the module circuit board before reaching the ground plane of the circuit board. Heat flows through the electrically insulating/heat conducting gasket to the module metal plate. The module metal plate directs most of the heat flow 18 - 2 towards the nearest module standoff (not shown) which transfers heat to the module metal support. The heat flow 18-3 of the PA flows along a similar path. The heat captured by the module metal plate is transferred to the module metal support (not shown). The integrated circuit packages on the master board transfer their heat through the PWB to the module metal support. For example, heat flow 18-4 from the integrated circuit IC-4 flows through the master board to the module metal support. Heat flows 18 - 5 from the components of the master board are carried towards thermal rails (not shown) by the module metal supports.

19 illustrates a top cross-sectional view of a phased array covered with an RF transparent radome. In other words, a radome is a shield that acts as a barrier to weather conditions in the external environment while allowing the passage of RF energy. The radome 19-2 is attached to the base plate 16-2 to form a sealed volume comprising an antenna, a module metal plate 2-1, module standoffs, a module metal support and a thermal rail. to form The thermal rails 16-3 are lengthened to create internal cavities A, B between the base plate 19-5 and the module metal support 12-1 in an enclosed environment. These cavities can be filled with the remaining electronics needed to operate the phased array. Thus, the electronic devices in the phased array are within an enclosed volume of the phased array. The enclosed volume within the radome protects all electronic devices from harsh weather conditions, but constitutes an enclosed volume that effectively uses convective heat to prevent exchange of heat generated by the enclosed electronic device with the external environment. The heat generated by the electronics within this enclosed section is instead removed by the use of a conductive heat flow formed by the metallic structural components of the phased array. A metal structural component may consist of individual parts, which may be secured together by gluing, welding, riveting, swaging, or using nuts and bolts. Swaging is a slot-peg system, in which a peg and a slot are joined together and two parts that fit together fit together. Some individual parts can be formed by bending a flat sheet of metal into doglegs or more complex contours. The finished structure of the metal construction component forms a metal skeleton that transfers heat from the electrical components to the outer fins of the phased array.

The heat pipe may also be mounted to a metal support to transport heat generated by the electronic components of the PA and phased array. The heat pipe absorbs heat from the metal support, evaporating the liquid in the sealed vessel and condensing it back to the liquid at the other end of the sealed vessel, releasing heat from the process. For example, the heat pipe may be in contact with the module metal plate 2-1 within a sealed portion of the system. The other end of the sealed vessel of the heat pipe may extend out of the sealed system to dissipate heat to the surrounding environment. The heat pipe will provide a highly thermally conductive path between any internal point in the enclosed system and any external point in the surrounding environment.

The heat pipe may also be mounted to the side of the base plate 16-4 attached to the fins 16-5. The heat pipe will assist in lateral conduction of heat along the base plate. The heat pipe can also be in direct contact simultaneously with the fins (slots in the fins that fit into the heat pipe) and the base plate. Heat from the base plate can easily diffuse laterally and to the fins simultaneously. This heat pipe structure can be used to extend the width of the base plate to dissipate heat over a large area. The heat pipe will provide a highly thermally conductive path between any two external points of the system within the surrounding environment.

19 illustrates how these metal structural components provide a conductive heat flow path from an electronic device within an enclosed volume to the external environment. The heat generated by these electronic components in the hermetically sealed phased array passes through the respective column rails (eg, 17-7a, 17-7b, 17-7c, 17-7d, etc.) to the base plate 16-4 ) flows to Base plate 16 - 4 collects and conductively transfers heat through the base plate to the opposite side of the base plate. On the opposite side of the base plate 16-4 are a plurality of metal pins 16-5 attached to the base plate. Heat from the base plate flows conductively to the plurality of fins as indicated by heat flows 19-4 through 19-7. The fins are partially surrounded by a protective shroud 19-3 on their sides. However, the lower and upper portions of the phased array corresponding to the positions of the pins 16 - 5 are open to the external environment. Accordingly, these fins are exposed to the external environment so that a convective heat flow 19 - 8 occurs between the fins and the air in the external environment. Optimally, the fins may be oriented perpendicular to the Earth's surface. As the fins are heated by conductive transfer of heat from the base plate 16-4, the heat from the fins is transferred to the air between the fins via convective heat flow. The heated air rises and flows out the top of the phased array. This introduces cooler air from the external environment causing a vacuum to enter the bottom of the vertically aligned phased array. The freshly drawn air undergoes convective heat flow from the fins extracting heat from the phased array and is expelled from the top of the phased array. The heat exchange process from the fins to the moving air between the fins extracts heat from the phased array. An electric fan may be disposed in the airflow path to force airflow between the fins. This airflow increases the velocity of the airflow and helps to extract a greater amount of heat from the fins in a given period of time. A dashed rectangle 19 - 1 comprising cavity A is further illustrated in FIG. 20 .

20 , in one embodiment, cavity A is a double-sided service circuit board 20-2 and similar components having an integrated circuit and discrete components 20-3 and 20-4. They are mounted on the board and filled. The service circuit board 20-2 is surrounded by a metal RF shield 20-1 to shield sensitive electronic devices from RF energy emitted by the antennas of the phased array. The shield is attached to the module metal support. The heat generated by the service circuit board flows along paths 20-6 and joins the heat flow 17-5 generated by the master board. Heat flow 17-6 from the module circuit board flows within the module standoffs. Heat streams 20 - 6 , 17 - 5 and 17 - 6 are collected by the thermal rail as heat stream 17 - 7a . Heat flow 17 - 7a along thermal rail 16 - 3 is transferred to base plate 16 - 4 . Heat flow from the thermal rail is transferred to the plurality of fins along and through the base plate. For example, heat flow 19 - 5 from the base plate flows to fins 16 - 5 . Similarly, the heat flow 17-7c of the other thermal rails is due to a combination of heat flow from the service board, master board and module circuit board. Heat is transferred to the base plate and a plurality of fins (eg, 19-4). The plurality of fins transfer heat from the base plate to convect the heat by convection.

Figure 21 shows the enlargement of the cavity by removing the middle row rails. The larger cavity AB allows a larger circuit board to be inserted into the cavity. An example of this cavity filled with a circuit board is illustrated in dashed-line rectangle 21-1 as shown in FIG. 22 . The service board now extends across the width of the phased array and, in one embodiment, has a plurality of integrated circuits in discrete components mounted on either side of the circuit board. The entire circuit board is surrounded by RF shields to prevent RF radiation from the antennas from interfering with the operation of the integrated and discrete component circuitry on the service circuit board. The heat generated by the service circuit board, master board and module circuit board is coupled in the thermal rails as heat flows 17-7c and 17-7d. Heat from the row rails flows to the base plate 16-4 and passes along the base plate to a plurality of fins (eg, 19-4 to 19-7) attached to the base plate. The plurality of fins transfer heat to the air between the fins.

Turning back to FIG. 21 , a right angle 21-2 of the plane including the line C-C' is shown in FIG. 23 . The base plate 16-4 is provided with the row rails 23-1 to 23-5. The middle row rail is subdivided into three parts: 23-2, 23-3 and 23-5. Wherever there is no middle row rail, define the creation of cavity AB, and the location of the third intermediate rail defines the formation of cavity A and cavity B. A circuit board formed in the large cavity AB is used to transmit signals between the circuit boards formed in the individual cavities of the cavity A and the cavity B. The lower rectangle and the three openings at the bottom of the base plate serve as conduits for passing signals to and from the electronics in the phased array.

The heat pipes may be connected between one row rail and another row rail or between the module metal support 12 - 1 and one of the row rails. For example, heat pipe 23-3 connects heat rail 23-3 to heat rail 23-2, or heat rail 23-3 contacts module metal support 12-1. may be connected to the column rail 23-2 including A heat pipe will provide a highly thermally conductive path between any two internal points of an enclosed system.

Figure 24 shows the complete module 24-1 after attaching the gasket of the module circuit board and the gasket to the lower surface of the module metal plate. The gasket may electrically insulate the module circuit board from the module metal plate. However, the gasket has a high thermal coefficient and transfers the heat generated by the circuit components on the circuit (particularly the PA) to the module metal plate. After assembly the module includes two cross pole antennas and at least one I/O connector. The module 24-1 is used as a building block constituting the phased array. 24 shows another embodiment of a module for a phased array. The module metal plate 24-2 has metal extensions 24-3. The metal extensions provide a large contact area to minimize thermal impedance and improve heat removal from the module metal plate. U.S. Provisional Application, titled "Modular Phased Array," filed July 22, 2015, for different types of module design and information on assembly, electrical and structural characteristics of the module, and other components of the module phased array. See No. 62/195,456, the entire contents of which are incorporated herein by reference. A cross-sectional view of 24-1 is shown in the following figure.

25 illustrates another embodiment of a cross-sectional side view 25 - 2 of the module in a plane perpendicular to the module metal plate. A right cross pole antenna comprising segments 1-8 and 1-9 is aligned at the intersection of the segments above aperture 8-1. The hole 8-1 consists of a hole formed in the module metal plate 24-2, together with a hole formed in the gasket 3-1, and an alignment of the hole in the module circuit board. The hole 8-1 creates an opening between the lead of the antenna positioned on one side of the module metal plate and the output lead of the PA mounted on the module circuit board (PWB) positioned on the other side of the module metal plate. Metal interconnects 8-2, insulated or exposed wires, can be used to connect the output leads of the PA to the input leads of the antenna. The wires and holes may be designed with different impedance values, but have the appropriate dimensions to create a coaxial electrical interconnect characterized by an impedance of about 50 ohms. In one embodiment, a metal interconnect is soldered to the leads on the top surface of the PWB, and the other end of the metal interconnect is soldered to the leads of the antenna. Other methods of connecting metal interconnects at one or both ends may be suitable as alternative embodiments of the present inventive subject matter. Examples are crimp-on connectors, plug and socket connectors, blade connectors, and the like.

Some or all of the electronic components associated with the PWB in the phased array may be shielded using RF shielding. The phased array's electrical system (antenna, PA output lead) generates a large amount of electromagnetic radiation that can be picked up by nearby electrical components. An RF shield is a metal sheath placed near these electronic components to isolate them from stray electromagnetic radiation. The RF shield attempts to create an enclosed environment for electrical components (not shown). The RF shield blocks electromagnetic radiation from interfering with the normal operation of other electrical components.

The left cross-pole antenna composed of segments 1-7 and 1-2 is electrically coupled to the module circuit board 4-1 in a similar manner. The module circuit board 4-1 has an exposed copper layer in contact with the gasket 3-1. On the opposite side of the circuit board, the surface is filled with at least one PA 8 - 3 , an integrated circuit 8 - 4 , discrete components and at least one I/O connector. The gasket is a flexible material and helps to compensate for any non-uniform height variations on the manufactured PWB ground plane side caused by manufacturing steps due to through holes or the like. In another embodiment of the present invention, all gaskets may be removed. For example, the ground plane metal of a PWB can be connected directly to the module metal plate using fasteners (screws, bolts, etc.) to hold the two parts together, or using paste, adhesive, or metal adhesive, etc. .

In another embodiment of the present invention, the PA may be attached directly (not shown) to the module metal plate 24 - 2 . In one embodiment, the PWB may have an opening into which the integrated circuit of the PA may be inserted and attached directly to the module metal plate. The heat generated by the PA will conduct the heat directly to the module metal plate through the integrated circuit. The PA's integrated circuit can be adhered to the module metal plate using a thermally conductive adhesive or paste. Wire bonds or tab attachments may couple electrical signals between the input/output pads of the PWB and PA. The output terminal of the PA may be connected to the antenna through the hole 8-1. The module metal plate 24-2 has a metal extension 24-3 that exposes a large metal contact area. This metal contact area can be used to transfer heat from the module metal plate.

In another embodiment of the present invention, the components may be mounted on the top side of the PWB 4-1 (see FIG. 25 ), which again normally contacts a heat conduction gasket that contacts the bottom of the module metal plate. The ground plane 3-1 is typically formed on this side of the PWB, however, a plurality of openings in the ground plane may be designed to mount these components on the top side of the PWB. In addition, the module metal plate may have a plurality of cutout areas corresponding to the module metal plate aligned with these components. Once the PWB is attached to the module metal plate, the cut out area is located at the bottom of the module metal plate through the heat transfer gasket or any other heat transfer conductive layer, as previously mentioned, the upper side of the ground plane of the PWB. provide space for these components to come into contact with

26 shows a perspective view of two separate modules 24-1 side by side. 27 illustrates the arrangement of two modules 24-1 together to form a component module 27-1. 28 illustrates a perspective view of a component module 27-1 related to another embodiment of the master board 28-1. The master board routes intermediate frequency (IF) and local oscillator (LO) signals to a plurality of component modules. The I/O connector 4-2 of the component module is aligned with the mating interface 11-2 located on the master board 28-1. The mating interface 11-2 is a male connector, the I/O connector 4-2 is a female connector, and the male/female connectors are interchangeable. When the I/O connector mates with the mating interface on the master board, the module circuit board can use the IF/LO network distributed on the master board. The master board 28-1 also has a large cutout opening 28-3 extending along most of the length of the board. The cutout opening provides the possibility to form a low thermal resistance path between the component modules and the base plate of the phased array, as will be described shortly. The cutout openings extend along a majority of the master board in one embodiment, allowing the master board to be manufactured as a single circuit board instead of being manufactured as two or more circuit boards. A master board manufactured as a single circuit board experiences an electrical environment with similar electrical characteristics experienced by all IF and LO signals propagating to or from all modules along the master board. Subdividing the master board into two or more circuit boards increases the mismatch in the electrical properties of the electrical traces provided to the propagating IF and LO signals. Mismatches in electrical characteristics between circuit boards can affect an important parameter known as "Synchronization Flight Time", which is undesirable. For a discussion of synchronized flight times, see Mihai Banu, Yiping Feng, and Vladimir Prodanov for a detailed description of "Low Cost, Active Antenna Arrays" US Patent Application No. 2012/0142280, published Jun. 7, 2012, and the The disclosure is incorporated herein by reference in its entirety.

29 shows a perspective view of the arrangement of heat transfer bars 29 - 1 (aka spacers or standoffs) relative to the master board 28 - 1 and the component module 27 - 1 . The heat transfer bars are metallic and provide a low thermal impedance path for heat from the module metal plate. The upper surface of the heat transfer bar is positioned to form a low thermal impedance contact to the metal surface associated with the metal extensions 24 - 3 of the module metal plate 24 - 2 . 30 shows the master board 28-1 and the heat transfer bar 29-1 fixed to the base plate 16-4. The base plate is in turn connected to pins 16-5. In FIG. 31 , the component module 27 - 1 is attached (electrically, physically and thermally) to the heat transfer bar 29 - 1 . The heat transfer bars are in turn connected (electrically, physically and thermally) to the base plate 16-4. Thermal fins 16-5 connected to the base plate provide a large surface area. This large surface area is used to convectively transfer heat from the fins to the air between the fins. Heat generated by the electrical components on the module circuit board is transferred to the module metal plate. The heat transfer bar provides a low thermal impedance path between the module metal plate and the base plate. The component module 27 - 1 is connected to the heat transfer bars 29 - 1 . The heat transfer bars are large enough that the cavity formed between the module metal plate 24-2 and the base plate can accommodate the master board 28-1 and connect the I/O connector 4-2 of each module to the master board. It is designed at a vertical height from the base plate 16-4 to ensure that it allows insertion into the mating interface 11-2 of the. The cutout opening 28-3 allows the heat transfer bar 29-1 to pass through the master board 28-1 and directly contact the base plate 16-4 to ensure efficient heat transfer between the module metal plate and the fins. make it possible

Each module metal plate 24-2 is attached to the heat transfer bars 29-1 by fasteners (not shown). These fasteners may be screws, nuts and bolts, quick release latches, and the like. The fasteners attaching the module metal plate to the heat transfer bars ensure both thermal and electrical connections between these two components. The thermal connection transfers heat generated by electrical components coupled to the module metal plate to the base plate and fins. The heat transfer bar 29-1, base plate 16-4, and heat fin 16-5 may be assembled as separate parts and connected together by fasteners or adhesives. The electrical connection ensures that the metal structures of the module metal plate and the base plate are at the same voltage potential. The module metal plate may be coupled to a voltage supply, eg, a ground potential, and serves as a ground plane for antennas mounted on the module metal plate. However, the structures of the two or more heat transfer bars 29 - 1 , the base plate 16 - 4 , and the heat fins 16 - 5 may be formed of one continuous metal part. Forming all three components into one unit would eliminate two interfaces: the heat transfer bar and base plate interface; Base plate and thermal pin interface. Removal of the at least one interface improves heat transfer and electrical properties through this removed interface. A cross-sectional view along the direction of the arrow 31-1 is presented next.

32 shows a cross-sectional view 31-1 of the assembled phased array. The antennas are mounted on the module metal plate, and the heat transfer bar 29-1 connects the module metal plate to the base plate 16-4. The module circuit board 4-1 may be connected to the lower side of the module metal plate through a gasket or other connection method. Other forms of attaching a circuit board to a metal plate have been discussed above and may include direct contact, adhesives or fasteners. The master board 28-1 is thermally and electrically connected to the base plate by a gasket 32-1 or other similar connection method as described above. A cutout in the master circuit board allows the intermediate heat transfer bar to thermally and electrically contact the module metal plate to the base plate. The heat transfer bar also provides the physical structure to connect the module metal plate to the base plate. The module circuit board is electrically connected to the master board by a connector formed by mating the I/O connector with the mating interface. The external heat transfer bar 29-3 connects and supports the other side of the module metal plate to the base plate 16-4. The heat transfer bar minimizes thermal impedance to heat flowing from the module circuit board to the fins connected to the base plate. The base plate adds additional structural support to the phased array and distributes the heat received from the heat transfer bars to the entire base plate. The distributed heat moves vertically into the base plate. Heat flows vertically and laterally to a number of fins 16-5 connected to the bottom of the base plate. An external protective shroud (if used) protects the outermost pins.

FIG. 33 is the region of FIG. 32 showing in more detail the flow of heat from components mounted on circuit boards (such as integrated circuits, active and passive components) down pins 16-5 through various structural components. 32-2) is exemplified. Only two of the plurality of pins are illustrated. The remaining plurality of fins (not shown) remove heat from the base plate in a similar manner. PAs dissipate a lot of heat during normal operation. A single PA can generate more than 25W of heat. A phased array with 100 antennas requiring a PA can produce as much as 2500W. The heat generated by each PA needs to be removed from the phased array through a low thermal impedance path to the external environment. This is one embodiment to achieve low thermal impedance. The white arrows indicate the direction of heat flow through the structural components forming the phased array. The thickness of each arrow (when indicating the magnitude of heat flow) may not be drawn to scale. Most of the structural components are made of metal except for the stacked layers of the PWB board. For example, the heat flow 33-1, 33-2 from the surface mounted integrated circuit IC-1 and the PA may flow through the stacked layers in the circuit board 4-1 before reaching the ground plane of the circuit board 4-1. flows perpendicular to the The gasket 3-1 ensures that the circuit board 4-1 maintains good thermal contact over the entire ground plane surface area of the circuit board. The gaskets may be alternately replaced with paste, adhesive or metal adhesive or the like, or may be connected by fasteners (screws, bolts, etc.) to fix the circuit board to the module metal plate. Heat flows to the module metal plate 24-2 through the low thermal impedance of the electrically insulating gasket 3-1 (if used).

The stacked layers of a PWB typically provide a high thermal impedance to heat flow. This large thermal impedance can be reduced if the area of the PA package is increased to help dissipate heat over a larger area. In addition, the actual layout of the PA circuit in an integrated circuit can also be redesigned and laid out over a larger surface area of the semiconductor. The heat generated by the power-consuming amplifier stage of the PA will spread over a larger area within the semiconductor, which will further help reduce the thermal impedance of the stacked layers of the PWB between the packaged device and the module metal plate.

The module metal plate 24 - 2 channels the heat flow 33 - 3 to the heat transfer bar 33 , which transfers the heat 33 - 6 to the base plate 16 - 4 . Most of the heat captured by the heat transfer bar is transferred to the base plate as indicated by heat flow 33-6 through the heat transfer bar (see FIG. 33). The lower surfaces of the metal extensions 24 - 3 of all the module metal plates substantially contact the upper surfaces of the heat transfer bars. The lower surfaces of the external heat transfer bars contact the upper surface of the base plate. However, the lower surface of the at least one intermediate heat transfer bar may have at least one notched position along the lower surface of the heat transfer bar. This notch in the heat transfer bar is sized to allow an unobscured placement of the at least one selected PWB between the two outer heat transfer bars. This distribution board may be one of the selected PWBs. This selected PWB allows multiple master boards in a phased array to be connected together via a single distribution board.

The integrated circuit packages on the master board transfer their heat vertically through the PWB to the base plate 16-4. For example, the heat flow 33 - 4 of the integrated circuit IC - 2 flows through the circuit board of the master board to the base plate 16 - 4 . The exposed metal layer of the master board may be in direct contact with the base plate. A gasket may not be necessary because the heat generated by the master board is much less than that of the module circuit board containing the PAs. The heat flow 33-6 from the heat transfer bar is split into a heat flow 33-5 and a heat flow 33-7. Heat flow 33 - 5 shows the lateral heat flow from the heat transfer bar carried by the base plate and traveling towards the remaining fins 16 - 5 (not shown).

One embodiment of a phased array uses aluminum as the metal forming the structural components: a module metal plate; heat transfer bars; base plate; pins; Protective shroud to reduce cost and weight. Although other metals are suitable as alternative embodiments of the subject matter of the present invention. Examples of metals having high thermal conductivity include, but are not limited to, copper, silver, zinc, nickel, iron, and the like. For example, metal alloys may be used in the construction of the system. To sufficiently transport heat, provide structural integrity, minimize cost, and minimize the weight of the phased array, the thickness of the metal component is about 3000 μm. Thicknesses greater than 3000 μm may be used if weight is not an issue, thicknesses less than 3000 μm provide less weight than at increased thermal resistance. Additionally, the type of metal used and the thickness used for each metal component are alternative embodiments of the present subject matter to achieve a phased array that achieves the desired cost, weight, heat extraction, and unit strength, respectively. , can be independently selected and adjusted.

34A shows a rear view of an assembled phased array illustrating an embodiment showing fins 16-5 connected to base plate 16-4 in a vertical orientation as indicated by vertical arrows; do. Heat from the phased array is transferred to the vertical fins. As the fins heat up, the air between the fins heats up and flows upwards. The air then exits the top of the phased array, carrying heat to the surrounding atmosphere. Fresh air is drawn in from the bottom to continuously carry heat from the phased array. 34B shows a rear view of an assembled phased array illustrating another embodiment in which the orientation of pins 16-5 connected to base plate 16-4 with respect to a vertical arrow is rotated at an angle from vertical. The pins 16 - 5 may be inclined at any one of a plurality of angles from the vertical direction. Heat from the phased array is transferred to the fins tilted at an angle. As the fins are heated, the air between the fins is heated and the air flow between the fins is brought into more contact with the fins, improving heat exchange between the fins and the air. The heated air exits the right side of the phased array and travels to the right, carrying the heat to the surrounding atmosphere. Fresh cooler air is drawn from the left side of the phased array between the fins to calculate the heat removal process. Heated air exiting from the right removes the heat generated by the phased array.

35 shows a bottom view of the phased array showing the modules, the master board and the distribution board. Four module outlines 24-2a, 24-2b, 24-2c, 24-2d are illustrated along the top. Each module is connected to the master board by a connector (not shown). The master board 28-1 has an opening 28-3 and a connector for coupling the master board and the distribution board 35-1. The master board 28-1 is separated into two long circuit boards by an opening 28-3, but connected together as a single unit by a common part of the circuit board 35-2. The electrical properties of the traces formed on a long circuit board will be similar because the board is simultaneously manufactured as a single unit. The two modules 24-2a and 24-2b form one instance of the component module 24-1. A second instance of component module 24-1 is formed by modules 24-2c and 24-2d. The modules are shaped to fit together when placed side by side. Note that the phased array can be increased in size in the positive/negative Y direction by adding more modules in each row and correspondingly extending the master board upward/downward, respectively. Similarly, if desired, the phased array can be increased in the X direction by adding more rows of modules and extending the master board to the right/left and including additional cutouts in the master board.

Fig. 36 shows the master board 36-2 from which the common part of the circuit board 35-2 has been removed. The circuit boards may be connected by a common part at the far end (not shown). In this case, the electrical properties of the traces formed on a long circuit board will be similar since the board is manufactured as a single unit. However, other embodiments will allow for four separate master boards along the top of the distribution board 35-1 and four separate master boards along the bottom of the distribution board. In this case each master board will be connected to the distribution board by its own connector.

Although not shown, the phased array of FIG. 32 may be covered with a radome. A radome is a shield that allows the passage of RF energy while acting as a barrier to weather conditions in the outdoor environment. The radome is attached to the base plate to form a sealed volume containing the antennas, the module metal plate and the heat transfer bars. Cavities may be formed in the phased array, and these cavities may be filled with the remaining electronics necessary to operate the phased array. Thus, the electronic devices in the phased array are within an enclosed volume of the phased array. The sealed volume within the radome protects all electronic devices from harsh weather conditions but also forms a sealed container. The enclosed volume prevents effective exchange of heat generated by the enclosed electronics with the external environment using convective heat. The heat generated by the electronics within this enclosed section is instead removed by the use of a conductive heat flow formed by the metallic structural components of the phased array. Metal structural components may be composed of separate parts, which may be held together by gluing, welding, riveting, swaging or the use of nuts and bolts. Swaging is a slot-peg system in which a peg and a slot are joined together and two parts that fit together fit together. The finished structure of the metal structural components forms a metal skeleton that transfers heat from the electrical component to the outer fins of the phased array. In another embodiment, some or all of the metal structural components may be configured as a single continuous unit in the system; This eliminates the metal-to-metal interface. The metal-to-metal interface may not form a uniform contact along the entire surface area. This can form islands of air gaps at the interface. These air gaps reduce heat flow across the interface. Removal of these metal-to-metal interfaces eliminates air gaps and improves heat transfer within the system.

Heat pipes may also be mounted to metal supports to transport heat generated by the electronic component of the PA and phased array. Heat pipes absorb heat from the metal supports to evaporate the liquid in the sealed container and condense back to the liquid at the other end of the sealed container to release heat from the process. For example, the heat pipe may contact the module metal plate 24 - 2 within an enclosed portion of the system. The other end of the sealed vessel of the heat pipe may extend out of the sealed system to dissipate heat to the surrounding environment. The heat pipe will provide a high thermal conductivity path between any internal points of the enclosed system to any external point in the surrounding environment.

Heat pipes may also be mounted to the side of the base plate 16-4 attached to the fins 16-5. The heat pipe will assist in lateral conduction of heat along the base plate. The heat pipe may also be in direct contact simultaneously with the fins (slots in the fins fitted to the heat pipe) and the base plate. Heat from the base plate can spread more easily laterally and to the fins at the same time. This heat pipe configuration can be used to extend the width of the base plate to dissipate heat over a large area. The heat pipe will provide a highly thermally conductive path between any two external points of the system in the surrounding environment.

Other embodiments are within the scope of the following claims. For example, any power dissipating integrated circuit components such as a microprocessor, DSP can use module ground plate technology to dissipate heat from component mounts on the PWB. In addition, network and portable systems include time division multiple access (TDMA), frequency division multiple access (FDMA), code division multiple access (CDMA), orthogonal frequency division multiplexing (OFDM), ultra-wideband (UWB), and Wi-Fi. , WiGig (WiGig), it is possible to exchange information wirelessly using communication technologies such as Bluetooth. Communication networks may include telephone networks, Internet Protocol (IP) networks, local area networks (LANs), ad hoc networks, local routers, and other portable systems.