Quad-band pcb antenna

<i>Background of the Invention</i>

Cross-Reference To Related Application

0001This application claims the priority benefits of <patcit id="pcit0001" dnum="US61165070A" dnum-type="L"><text>U.S. provisional Application No. 61/165,070 filed March 31, 2009</text></patcit>.

Field of the Invention

0002Embodiments of the present disclosure relate to surface mount antennas that may be disposed on printed circuit boards (PCBs). More particularly, the present disclosure relates to a quad-band antenna that may be surface mounted on PCBs.

Discussion of Related Art

0003Security or alarm systems are installed in premises to detect hazardous or potentially hazardous conditions. A security system generally includes a plurality of detectors/sensors, one or more keypads, and a control panel containing the system electronics and may include a communication interface (communicator) for remote monitoring and two-way communication over telephone or wireless communication paths. Each of the detectors communicates with the control panel to provide notification of an alarm condition. Examples of possible alarm conditions include unauthorized entry or the unexpected presence of a person who may be an intruder, fire, smoke, toxic gas, high/low temperature conditions (e.g., freezing), flooding, power failure, etc. In other words, an alarm condition may represent any detectable condition that might lead to personal hazard or property damage. Audible and/or visible alarm devices such as sirens, lights, etc., may also be utilized to notify occupants of the existence of an alarm condition. The control panel may be located in a utility room, basement, etc., and may communicate with the detectors and notification devices by wired or wireless signal paths. A keypad, which may also communicate with the control panel via a wired or wireless connection, is used to arm/disarm the system as well as providing a means to display various system messages via a status display screen.

0004<figref idref="f0001">Fig. 1</figref> is a block diagram of a typical security system 10 installed in a building or premises. Security system 10 includes a control panel 20 which generally controls operation of the system. A number of detection devices 18₁...18_N are utilized to monitor an area. Detection devices may include, for example, motion detectors, door contacts, glass break detectors, smoke detectors, water leakage detectors, gas detectors, etc. Detection devices 18₁...18_N communicate with panel 20 by a dedicated wired interconnect 18A, wirelessly 18B, through the electric (i.e. power) wiring of the premises 18C, or otherwise. One or more user interfaces, such as keypad 25, is used to communicate with control panel 20 to arm, disarm, notify, and generally control system 10.

0005Control panel 20 communicates with each of the detection devices 18₁...18_N, keypad 25 and personal device 19 as well as communicating with an offsite monitoring service 30 which is typically geographically remote from the monitored premises in which system 10 is installed. Control panel 20 may include a CPU 34, memory 35, and communicator 36. CPU 34 functions as a controller to control the various communication protocols within system 10. Memory 35 stores system parameters, detection device information, address information, etc. Communicator 36 sends and receives signals to/from the monitoring facility 30 via communications link 31. Alternatively, communicator 36 may be a separate device that communicates with controller 20 via a hardwired or wireless connection.

0006Generally, when an alarm condition occurs based on the operation of one or more detection devices 18₁...18_N, a signal is transmitted from the respective detection device to control panel 20. Depending on the type of signal received from the one or more detection devices, communicator 36 communicates with monitoring service 30 via link 31 to notify the monitoring service that an alarm notification has occurred at the premises. Communication link 31 may be a POTS (Plain Old Telephone System) connection, a broadband connection (e.g., internet), a cellular link such as GSM (Global System for Mobile communications) transmission, satellite communication, etc. In certain security systems, keypad 25, control panel 20 and communicator 36 may be housed within a single unit.

0007For wireless communication, the keypad 25, control panel 20, communicator 36, and detection devices 18₁...18_N include an antenna for transmitting and receiving signals. However, the size of communicator 36 and other components of the security system are continually being decreased in order for the devices to be unobtrusively installed in various areas of the home or business. For security providers that do business throughout the world, the decreasing sizes of the components of the security system, and consequently the PCBs within the components, often requires the design and manufacture of separate PCBs due to the different bands used for wireless communication in these different regions. For example, security units in North America typically operate in the Global System for Mobile Communications (GSM) 850 and GSM900 bands, and security units in Europe typically operate in the GSM1800 and GSM1900 bands. Accordingly, a compact quad-band surface mount antenna is desirable that can accommodate different GSM bands. Examples of similar multiband antennas are described in <patcit id="pcit0002" dnum="WO2009028251A"><text>WO2009/028251</text></patcit> and <patcit id="pcit0003" dnum="US20070103367A"><text>US2007/0103367</text></patcit>.

Summary of the Invention

0008According to the present invention there is provided a planar antenna including a ground plane, a feed line, and a radiating element in an arrangement as set out in claim 1.

Brief Description of the Drawings

0009<ul id="ul0001" list-style="none" compact="compact"><li><figref idref="f0001">FIG. 1</figref> illustrates a prior art block diagram of a security system.</li><li><figref idref="f0002">FIG. 2</figref> illustrates a layout of a quad-band surface mount antenna.</li><li><figref idref="f0003">FIG. 2A</figref> illustrates the quad-band surface mount antenna operating in a first resonant mode.</li><li><figref idref="f0004">FIG. 2B</figref> illustrates the quad-band surface mount antenna operating in a second resonant mode.</li><li><figref idref="f0005">FIG. 2C</figref> illustrates the quad-band surface mount antenna operating in a third resonant mode.</li></ul>

Description of Embodiments

0010The present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention, however, may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, like numbers refer to like elements throughout.

0011<figref idref="f0002">Fig. 2</figref> is a layout of one example of a quad-band surface mount antenna 100 used for transmitting and receiving wireless communication signals. Antenna 100 may be disposed on a dielectric substrate 50 such as a printed circuit board (PCB). Antenna 100 includes a ground plane 102 and radiating element 104 disposed on one side of a substrate or PCB 50 and a feed line 106 disposed on an opposite side of the substrate 50. Radiating element 104 includes a first portion 108 extending from ground plane 102 in a substantially perpendicular direction with respect to the direction in which ground plane 102 extends across PCB 50. A second portion 110 of radiating element 104 extends from first portion 108 in a substantially perpendicular direction such that second portion 110 may extend parallel to ground plane 102 and defines a non-conducting slot 112 with ground plane 102.

0012A third portion 114 of radiating element 104 extends from second portion 110 in a substantially perpendicular direction such that it is substantially parallel with first portion 108. Third portion 114 includes an enlarged portion 116 having a substantially rectangular geometry. However, third portion 114 may have alternative geometries based on the desired configuration of radiation element 104. Fourth portion 118 extends from third portion 114 in a substantially perpendicular direction and is substantially parallel with ground plane 102 and second portion 110.

0013As will be described in more detail with reference to <figref idref="f0003 f0004 f0005">Figs. 2A-2C</figref>, by utlizing various active portions of the layout of antenna 100, quad-band operation is provided using only a single feed line 106 in three resonant modes. One resonant mode may be, for example, for use in the Global System for Mobile Communications (GSM) 850 and GSM900 frequency bands. The GSM850 frequency band is between 824-849 MHz for uplink and between 869-894 MHz for downlink, and the GSM900 frequency band is between 890-915 MHz for uplink and 935-960 MHz for downlink for a total bandwidth of 136 MHz.

0014<figref idref="f0003">FIG. 2A</figref> illustrates an exemplary configuration of the active portion of antenna 100 when operating in a first resonant mode. The active portion of antenna 100 extends from ground plane 102 to fourth portion 118 of radiating element 104. The active portion of antenna 100 for the first resonant mode intersects feed line 106 at an intersection point such that a partial wavelength radiating element 104, which in this example is a ¼ wavelength, is disposed adjacent to the intersection point and extends across the third and fourth portions 116, 118 of radiating element 104. As will be understood by one skilled in the art, the length of partial radiating element 124 may be adjusted to resonate in response to signals having frequencies greater than or less than those of GSM850 and GSM950 frequency bands.

0015<figref idref="f0004">FIG. 2B</figref> illustrates an exemplary configuration of the active portion 126 of antenna 100 when antenna 100 is operating in a second resonant mode, which may be, for example, in response to signals in the GSM1850 band. As shown in <figref idref="f0004">FIG. 2B</figref>, active portion 126 extends along the perimeter of conducting slot 112 defined by ground plane 102 and the first and second portions 108, 110 of radiating element 104. Active portion 126 forms a ¼ wavelength radiating element excited by the feed line 106 disposed on the opposite side of the PCB 50. The frequency at which active portion 126 resonates may be adjusted by increasing or decreasing the perimeter of slot 112.

0016<figref idref="f0005">FIG. 2C</figref> illustrates an exemplary configuration of the active portion 128 of antenna 100 when antenna 100 is operating in a third resonant mode, which may be, for example, in response to signals having a frequency in accordance with the GSM1900 frequency band. Active portion 128 of radiating element 104 is a ½ wavelength loop, however alternative configurations may be employed based on the desired frequency. The active portion extends along first and second portions 108, 110 of radiating element 104 and partially along third portion 114 that defines slot 130 with second portion 110. Feed line 106 also resonates as a part of active portion such that active portion has a shape defining a pair of rectangles, which are coupled together at point 136 where feed line 106 intersects second portion 110 of radiating element 104.

0017The antenna 100 disclosed herein advantageously resonates in three resonant modes to provide quad-band operation while having a compact design. Antenna 100 enables security system providers and other organizations providing wireless communications, a compact surface mount antenna disposed on a PCB that may be utilized in various regions to accommodate wireless transmission in different frequency bands.

0018While the present invention has been disclosed with reference to certain embodiments, numerous modifications, alterations and changes to the described embodiments are possible without departing from the sphere and scope of the present disclosure, as defined in the appended claims. Accordingly, it is intended that the present invention not be limited to the described embodiments, but that it has the full scope defined by the language of the following claims, and equivalents thereof.