Antenna assembly and multibeam antenna assembly

The present invention relates to an antenna device and a multi-beam antenna device used for a fixed radio device and a terminal radio device of a wireless LAN system.

In high-speed wireless communication such as a wireless LAN system, there is a problem that transmission quality deteriorates due to multipath fading and shadowing, which is particularly remarkable indoors. Therefore, sector antennas have been studied as one means for avoiding such deterioration of transmission quality. In this sector antenna, a plurality of antenna elements whose main beams are directed in different directions are arranged, and the plurality of antenna elements are selectively switched according to the radio wave propagation environment. In addition, in general, antennas mounted on fixed radios installed on the ceiling and terminal radios for notebook computers used on desks are required to have a flat structure from the viewpoint of production and portability. Be done. In addition, considering the indoor communication environment, it is desirable that the directivity of these antennas is such that the elevation angle of the main beam is tilted from the vertical direction to the horizontal direction with respect to the antenna surface, and further, the installation of the communication destination Considering the position, it is desirable to be able to control this tilt angle.

As a sector antenna that realizes such radiation characteristics tilted in the horizontal direction, a planar multi-sector antenna using the "slot Yagi-Uda array" described in Non-Patent Document 1 has been proposed. This multi-sector antenna will be described with reference to FIG. This multi-sector antenna is formed by arranging six slot arrays 102A to 1102F radially on a substrate 101, and each of the six slot arrays 102A to 102F is composed of slots of five elements. As a single characteristic of this slot array, the main beam is formed in the direction in which the elevation angle θ of the vertical surface is 60 degrees, and the half-value angle of the conical surface pattern is about 56 degrees. This multi-sector antenna constitutes a 6-sector antenna in which 360 degrees of the horizontal plane is divided into 6 by arranging 6 slot arrays on the horizontal plane at intervals of 60 degrees and selectively feeding each slot array. For example, if the operating frequency is 5 GHz, the size of this sector antenna is 273 mm (4.55 wavelength) in diameter L7 and 58535 square mm in area.

Further, as another antenna, a multi-sector antenna using the "waveguide element shared patch Yagi-Uda array" described in Patent Document 1 has been proposed. This multi-sector antenna will be described with reference to FIG. In this multi-sector antenna, the waveguide elements 203A to 203F of rectangular patches are arranged radially around the regular hexagonal waveguide element 202 while being formed on the surface of the circular dielectric substrate 201, and further, the waveguide elements 203A to 203F are arranged radially. Feeding elements 204A to 204F are arranged outside the waveguide elements 203A to 203F. In this way, the three rows of waveguide elements intersect with each other at an angle of 60 degrees around the regular hexagonal waveguide element 202 to form a six-row patch Yagi-Uda array. Here, when one feeding element is fed, the waveguide element train including the regular hexagonal waveguide operates as a Yagi-Uda array. At this time, the main beam is formed in the direction in which the elevation angle θ of the vertical surface is 45 degrees, and the half-value angle of the conical surface pattern is about 63 degrees. In this way, by selectively feeding the feeding element, it is possible to configure a 6-sector antenna in which 360 degrees of the horizontal plane is divided into 6 parts. The dimensions of this sector antenna are, for example, if the operating frequency is 5 GHz, the diameter L8 is 1.83 wavelengths (110 mm) and the area is 9503 square mm.<nplcit num="1"><text>Journal of the Institute of Electronics, Information and Communication Engineers (B), Vol.J85-B, No.9, pp1633-1643, Sep. 2002.</text></nplcit><patcit num="1"><text>Japanese Unexamined Patent Publication No. 2003-142919</text></patcit>

<p> However, among the above-mentioned multi-sector antennas, the flat multi-sector antenna using the former "slot Yagi-Uda array" requires slot arrays for the number of sectors in order to operate each slot array independently for each sector. However, there is a problem that the plane dimension becomes large. Further, since the elevation angle θ of the main beam is constant at 60 degrees on the vertical plane, there is a problem that the communication quality tends to deteriorate depending on the installation position of the communication destination.</p><p> In addition, the multi-sector antenna using the latter "waveguide element shared patch Yagi-Uda array" uses multiple patches with a side of about 1/2 wavelength as the antenna element, so there is a problem that the plane size becomes large. is there. Further, since the main beam direction is constant at 45 degrees on the vertical plane, there is a problem that the communication quality tends to deteriorate depending on the installation position of the communication destination.</p><p> The present invention has been made in view of the above circumstances, and has a small planar structure that can be easily mounted on a small radio, forms a vertically polarized main beam tilted in the horizontal direction, and further, the main beam direction in the vertical plane. It is an object of the present invention to provide an antenna device and a multi-beam antenna device capable of controlling the above.</p>

<p> In the antenna device of the present invention, a first slot element having an electric length of about 1/2 wavelength and a second slot having an electric length of about 1/2 wavelength are arranged in parallel on a conductor plate at a predetermined interval. An element, a reflecting plate arranged at a predetermined distance parallel to the conductor plate, and a predetermined distance between the conductor plate and the reflecting plate so as to be orthogonal to the first and second slot elements. The first to fourth linear non-feeding elements arranged in series with each other are provided between the first and second linear non-feeding elements, and the first and second linear non-feeding elements are electrically connected. The third and fourth linear non-feeding elements are provided between the first switching element for switching between the connected state and the non-connected state and the third and fourth linear non-feeding elements. It is characterized by including a second switching element that switches between an electrically connected state and a non-connected state. With this configuration, it is possible to realize a compact multi-beam antenna having a planar structure and capable of switching the main beam in the low elevation angle direction and the high elevation angle direction on a vertical plane.</p><p> Further, the antenna device of the present invention has an electric length of about 1/2 wavelength arranged in parallel with the conductor plate at a predetermined interval so as to be orthogonal to the first and second slot elements. A predetermined interval is provided so that the 3rd slot element and the 4th slot element are flush with the 1st to 4th linear non-feeding elements and orthogonal to the 3rd and 4th slot elements. The 5th to 6th linear non-feeding elements provided between the 5th to 8th linear non-feeding elements arranged in series with each other and the 5th and 6th linear non-feeding elements, and the 5th and 6th linear non-feeding elements are provided. The seventh and eighth linear non-feeding elements provided between the third switching element for switching between the electrically connected state and the unconnected state and the seventh and eighth linear non-feeding elements. It is characterized by being provided with a fourth switching element that switches between a state in which the antenna is electrically connected and a state in which the antenna is not connected. According to this configuration, it is possible to realize a small four-direction sector antenna having a planar structure and capable of switching the main beam direction on a vertical surface.</p><p> Further, the antenna device of the present invention has four slot elements having a side having a length of about 1/4 wavelength to 3/8 wavelength and arranged in a diamond shape on the conductor plate, and a fifth slot element. It is connected to the first power feeding means for supplying power to the position where one end and one end of the sixth slot element are connected, and the other end of the fifth slot element and one end of the seventh slot element, and has approximately 1/4 wavelength. The first slot bypass element having a folded shape while maintaining the length of the above, and the other end of the sixth slot element and one end of the eighth slot element are connected to each other and have a length of about 1/4 wavelength. A second slot bypass element having a folded shape, a reflecting plate arranged at a position parallel to the conductor layer at a predetermined distance, and a connection portion of the fifth and sixth slot elements. Ninth to twelfth linear non-feeding powers arranged in series parallel to the line connecting the connecting portions of the seventh and eighth slot elements and at a predetermined interval between the conductor plate and the reflecting plate. A fifth, which is provided between the element and the 9th and 10th linear non-feeding elements, and switches between a state in which the 9th and 10th linear non-feeding elements are electrically connected and a state in which the 9th and 10th linear non-feeding elements are not connected. A sixth that is provided between the switching element and the eleventh and twelfth linear non-feeding elements to switch between a state in which the eleventh and twelfth linear non-feeding elements are electrically connected and a state in which the linear non-feeding elements are not connected. It is characterized by being provided with a switching element of. According to this configuration, it is possible to realize a compact two-direction multi-beam antenna capable of switching the main beam in the low elevation angle direction and the high elevation angle direction in the vertical plane with a planar structure.</p><p> Further, the antenna device of the present invention is characterized in that the second power feeding means is arranged at a position where the other end of the seventh slot element and the other end of the eighth slot element are connected. According to this configuration, it is possible to realize a compact four-direction multi-beam antenna capable of switching the main beam in the low elevation angle direction and the high elevation angle direction in the vertical plane with a planar structure.</p><p> Further, in the antenna device of the present invention, the slot element and the slot bypass element are formed of a copper foil pattern on the front surface of the dielectric substrate, and the linear non-feeding element is copper on the back surface of the substrate. It is characterized by being composed of a foil pattern. According to this configuration, it is possible to realize a highly productive antenna device that can be easily manufactured.</p><p> Further, in the antenna device of the present invention, the distance between the conductor plate and the reflection plate is set to about 1/4 wavelength or more and about 1/2 wavelength or less, and the slot element and the linear non-feeding element are used. The interval is set to about 1/6 wavelength or more and about 1/4 wavelength or less. According to this configuration, the main beam can be switched between the low elevation angle direction and the high elevation angle direction on the vertical plane, and the angle change on the vertical plane can be made large.</p><p> Further, in the antenna device of the present invention, the thickness of the dielectric substrate is set to about 1/6 or more and about 1/4 or less of the effective wavelength in the dielectric, and the copper foil pattern on the back surface of the substrate is used. The distance from the reflector is set to about 1/4 or more of the free space wavelength and about 1/3 or less. According to this configuration, the main beam can be switched between the low elevation angle direction and the high elevation angle direction on the vertical plane, and the angle change on the vertical plane can be made large.</p><p> Further, the multi-beam antenna device of the present invention is characterized in that the plurality of antenna devices according to any one of claims 1 to 7 are arranged equiangularly on a plane. According to this configuration, it is possible to realize a sector antenna having a planar structure and forming a main beam in a desired direction.</p>

<p> According to the present invention, the first and second slot elements having an electric length of about 1/2 wavelength are arranged in parallel at a predetermined interval, and a reflector is provided at a predetermined interval from the arrangement surface of the slot elements. A plurality of linear non-feeding elements are formed between the arrangement surface of the slot element and the surface of the reflector so as to be orthogonal to the slot element, and the slot elements are fed by phase difference and the linear non-feeding element is provided. By adjusting the length by switching between connected and unconnected with a switching element, it is possible to form a vertically polarized main beam tilted in the horizontal direction in the low elevation angle direction and the high elevation angle direction, and the phase difference. The main beam direction can be switched even in a horizontal plane by adjusting the above, and a compact multi-beam antenna device having a flat structure can be realized.</p><p> Further, according to the present invention, two sets of two slot elements arranged in parallel are provided, and the two sets of slot elements are arranged so that their radial directions are orthogonal to each other, whereby a compact 4-sector antenna having a planar structure is provided. Can be realized. Further, slot elements having a length of about 1/3 wavelength are arranged in a square shape, slot bypass elements are provided at each pair of opposing vertices, and further, at predetermined intervals parallel to the arrangement surface of the slot elements. A reflective plate is arranged at a position separated from each other, a plurality of linear non-feeding elements are formed between the arrangement surface of the slot element and the reflective plate surface, and the linear non-feeding elements are connected / disconnected by a switching element. By switching and adjusting the length, it is possible to realize a small and planar multi-beam antenna capable of forming a vertically polarized main beam tilted in the horizontal direction in the low elevation angle direction and the high elevation angle direction.</p>

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. [First Embodiment] FIG. 1 shows the configuration of an antenna device according to the first embodiment of the present invention, in which the antenna device includes a substrate 11 formed of a dielectric material and a copper foil layer 12. , The slot elements 13A and 13B, the reflector 14, the non-feeding elements 15A to 15D, the switching elements 16A and 16B, and the feeding portions 17A and 17B are provided. In this embodiment, the operating frequency of the antenna will be described as 5 GHz.

The substrate 11 has, for example, a relative permittivity εr of 2.6, a thickness t of 8 mm (0.21 wavelength (effective wavelength in the dielectric)), and dimensions L1 × L2 of 44 mm × 46 mm (0.73 wavelength × 0.77 wavelength). is there. The copper foil layer 12 is composed of a copper foil adhered to the + Z side surface of the substrate 11. The slot elements 13A and 13B are voids formed by cutting the copper foil layer 12, for example, having a length of 18.5 mm (about 0.5 wavelength) and a width of 1 mm. These slot elements 13A and 13B are arranged in parallel with an element spacing d1 of, for example, 20 mm, and are formed in the center of the substrate 11. The reflector 14 is a conductor plate arranged at a position separated from the surface on which the slot elements 13A and 13B are arranged by a distance h of, for example, 25 mm (0.42 wavelength) on the -Z side. The non-feeding elements 15A to 15D are formed by a copper foil pattern on the -Z side surface of the substrate 11, and have a length L3 of about 10 mm (about 0.27 wavelength). The non-feeding elements 15A to 15D are arranged in series in the center of the substrate 11 so as to be orthogonal to the slot elements 13A and 13B. The switching elements 16A and 16B are composed of, for example, a PIN diode. Of these, the switching element 16A is connected to the non-feeding element 15A and the non-feeding element 15B, while the switching element 16B is connected to the non-feeding element 15C and the non-feeding element 15D. When a reverse bias is applied to the switching elements 16A and 16B, the PIN diode is turned off and opened, so the non-feeding element 15A and the non-feeding element 15B, and the non-feeding element 15C and the non-feeding element 15D are not connected. Become. When a forward bias is applied to the switching elements 16A and 16B, the PIN diode is turned on and short-circuited. Therefore, the non-feeding element 15A and the non-feeding element 15B, and the non-feeding element 15C and the non-feeding element 15D are connected respectively, and two non-feeding elements of about 20 mm (about 0.54 wavelength) are arranged in series. It is equivalent to the state of being.

Next, in the antenna device having the above-described configuration, the operation when the slot elements 13A and 13B are phase-difference excited will be described. The slot elements 13A and 13B are excited by the feeding units 17A and 17B, respectively. For example, it is assumed that the excitation phase of the feeding unit 17A at this time is delayed by about 50 degrees from the excitation phase of the feeding unit 17B.

(I) First, the operation when a reverse bias is applied to the switching elements 16A and 16B will be described. When the reverse bias is applied, the non-feeding elements 15A to 15D are not electrically connected, so their lengths are sufficiently shorter than the half wavelength of the operating frequency and do not affect the antenna characteristics. FIG. 2 is an operation explanatory view showing the state at this time, and the effect of the reflector 14 is modeled by the principle of mapping, focusing only on the vertical (XZ) plane. In FIG. 2, the slot elements 13A and 13B shown in FIG. 1 are modeled by the point wave sources 21A and 21B. Image of point wave sources 21A and 21B The wave sources 22A and 22B are assumed to be symmetrical with respect to the reflector 14, that is, 2h (50 mm (0.84 wavelength)) away from the -Z side. The excitation phases of the image wave sources 22A and 22B at this time are 180 degrees inverted with respect to the excitation phases of the point wave sources 21A and 21B, respectively. By synthesizing the radiation from the above four wave sources, the main beam is formed in the direction tilted 60 degrees from the + Z direction to the + X side. At this time, the main polarization component becomes the vertically polarization Eθ component.

FIG. 3 is a radiation pattern showing the directivity of the antenna device shown in FIG. 1 when a reverse bias is applied to the switching elements 16A and 16B. In FIG. 3, (A) shows the directivity of the vertical (XZ) plane, and (B) shows the directivity of the conical surface at an elevation angle θ of 60 degrees. In FIG. 6A, the directivity a indicates the directivity of the vertically polarized wave Eθ component, and it can be confirmed that the main beam tilted in the direction of the elevation angle θ of 60 degrees is obtained. Further, in FIG. 3B, the directivity b shows the directivity of the vertically polarized wave Eθ component as in the directivity a, and it can be confirmed that the main beam is directed in the + X direction. At this time, the directivity gain of the main beam is 12.3 dBi, and the half-value angle of the conical surface pattern is 87 degrees.

(II) Next, the operation when a forward bias is applied to the switching elements 16A and 16B will be described. If the forward bias is applied, the parasitic element 15A and the parasitic element 15B, the parasitic element 15C and the parasitic element 15D is shaped connected respectively to become on purpose, be linear element of about 0.54 wavelength, reflective element Will operate as. This is the same as the state in which the position of the reflector 14 is pseudo-closed to the slot element. Fig. 4 is a model that models the state at this time by the principle of mapping and focuses only on the vertical (XZ) plane. In the figure, the slot elements 13A and 13B are modeled by the point wave sources 31A and 31B. Image of point wave sources 31A and 31B The wave sources 32A and 32B are assumed to be symmetrical to the reflecting element, that is, 2t (16mm (0.27 wavelength)) away from the -Z side. By synthesizing the radiation from these four wave sources, the main beam is formed in the direction tilted 30 degrees from the + Z direction to the + X side. At this time, the main polarization component becomes the vertically polarization Eθ component.

FIG. 5 is a radiation pattern showing the directivity of the antenna device shown in FIG. 1 when a forward bias is applied to the switching elements 16A and 16B. In FIG. 5, (A) shows the directivity of the vertical (XZ) plane, and (B) shows the directivity of the conical surface at an elevation angle θ of 30 degrees. In FIG. 5 (A), the directivity c indicates the directivity of the vertically polarized wave Eθ component, and it can be confirmed that the main beam tilted in the direction of the elevation angle θ of 30 degrees is obtained. Further, in FIG. 5 (B), the directivity d shows the directivity of the vertically polarized wave Eθ component as in the directivity c, and it can be confirmed that the main beam is directed in the + X direction. At this time, the directivity gain of the main beam is 9.4 dBi, and the half-value angle of the conical surface pattern is 86 degrees.

In this way, by exciting the slot element 13A with a delay of about 50 degrees with respect to the slot element 13B, a main beam tilted to the + X side is obtained, and the lengths of the non-feeding elements 15A to 15D are switched by the switching element. This makes it possible to switch the main beam direction in the vertical (XZ) plane. When the slot element 13A is excited with respect to the slot element 13B about 50 degrees earlier, a main beam tilted to the -X side can be obtained. Therefore, by using the antenna configuration shown in FIG. 1, the main beams in four directions are obtained. Can be formed. Further, when the main beam is formed in the low elevation angle direction of the elevation angle θ of 60 degrees, the gain is high, and when the main beam is formed in the high elevation angle direction of the elevation angle θ of 30 degrees, the gain is low. It is suitable for antennas for fixed stations and card-type terminals that are inserted into laptop computers. A fixed station installed on the ceiling does not require a high gain because the high elevation angle direction is toward the floor, and a high gain is required because it communicates with a distant terminal in the low elevation angle direction.

As described above, according to the present embodiment, two slot elements are arranged in parallel at predetermined intervals on the front surface of the substrate, and a plurality of linear non-feeding elements are arranged on the back surface of the substrate so as to be orthogonal to the slot elements. In addition, a reflector is provided at a predetermined distance from the slot element to feed the slot element with a phase difference, and the linear non-feeding element is switched between connected and unconnected by the switching element to increase the length. I'm adjusting. As a result, the main beam can be switched between a low elevation angle direction and a high elevation angle direction on a vertical plane with a small and planar structure. Furthermore, by adjusting the phase difference of the slot element, it is possible to realize a multi-beam antenna capable of switching the main beam direction even in a horizontal plane.

In the present embodiment, the distance h between the slot element and the reflector has been described as 25 mm (0.42 wavelength), but the vertical plane tilt angle α can be changed by changing the distance h. When the non-feeding element is not operated as a reflecting element, the vertical plane tilt angle α tends to decrease when the distance h is reduced, and the vertical plane tilt angle α tends to increase when the distance h is increased. However, if the distance h is increased, a back lobe will occur in the direction opposite to the main beam direction in the -X direction, so the distance h according to the application should be in the range of 1/4 wavelength to 1/2 wavelength. It is desirable to choose properly. In the present embodiment, the distance h is 0.42 wavelength (the electrical distance is about 0.5 wavelength when the thickness of the substrate is taken into consideration), the F / B ratio is good, and the vertical plane tilt angle is the largest value. Further, this value is for increasing the angle difference at the time of switching the vertical plane beam, and is set so that the main beam is directed in the low elevation angle direction as much as possible when the non-feeding element is not operated as the reflecting element.

Further, in the present embodiment, the thickness t of the substrate has been described as 8 mm (0.21 wavelength), but when the non-feeding element is operated as a reflecting element by changing this thickness t, the thickness t is reduced. Then, the vertical plane tilt angle tends to be small, and the vertical plane tilt angle tends to be large when the thickness t is increased. Therefore, it is desirable to appropriately select the thickness t in the range of 1/6 wavelength to 1/4 wavelength according to the application. In the present embodiment, the thickness t is set to 0.21 wavelength, which is a value that optimizes the vertical plane tilt angle and the F / B ratio in the high elevation angle direction, and also increases the angle difference when switching the vertical plane beam. It is set to do. Further, in the present embodiment, the thickness of the substrate has been described as 8 mm, but the same effect can be obtained even if the resin is sandwiched between the substrates formed of two thin dielectrics.

Further, in the present embodiment, the configuration in which the slot element is directly fed is described, but the same effect can be obtained by the configuration in which the slot element is fed by using the microstrip line. At this time, as a phase difference feeding method, it can be realized by a T-branch circuit, a π-branch circuit, or the like. Further, in the present embodiment, the slot element is formed by a copper foil pattern on the substrate, but the same effect can be obtained even if the slot element is formed by providing a gap in the conductor plate, for example. At this time, considering the wavelength shortening by the substrate, it is necessary to widen the distance between the slot element and the reflector. Further, in the present embodiment, a PIN diode is used as the switching element, but the same effect can be obtained by using another device such as a FET.

[Second Embodiment] Next, the antenna device according to the second embodiment of the present invention will be described in detail with reference to the drawings. However, in the present embodiment, the same parts as those in the first embodiment shown in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted. In this embodiment as well, the operating frequency of the antenna will be described as 5 GHz. FIG. 6 shows the configuration of the antenna device according to the second embodiment of the present invention, which includes slot elements 41A and 41B in addition to the slot elements 13A and 13B, and relates to the first embodiment. It has a configuration in which two sets of antenna devices are arranged orthogonally.

The slot elements 41A and 41B are voids formed by cutting the copper foil layer 12, for example, having a length of 18.5 mm and a width of 1 mm. The slot elements 41A and 41B are arranged so as to be orthogonal to the slot elements 13A and 13B with the same 20 mm as the element distance d1 between the slot elements 13A and the slot elements 13B, and form a square shape together with the slot elements 13A and 13B. The non-feeding elements 42A to 42D are formed by a copper foil pattern on the -Z side surface of the substrate 11, and have the same length L3 as the non-feeding elements 15A to 15D, which is 10 mm (about 0.27 wavelength). The non-feeding elements 42C to 42D are arranged in series in the center of the substrate 11 so as to be orthogonal to the slot elements 41A and 41B and the non-feeding elements 15A to 15D.

Next, the operation of the antenna device according to the present embodiment described above will be described. In the figure, the slot elements 13A and 13B and the slot elements 41A and 41B are selectively excited, respectively. That is, when the slot elements 13A and 13B are phase-difference excited, the main beam is switched in the ± X direction, and when the slot elements 41A and 41B are phase-differentiated excited, the main beam is switched in the ± Y direction. .. At this time, the slot element that is not excited is short-circuited at the center of the element, for example. As described above, the phase difference excitation of the slot elements 13A and 13B and the phase difference excitation of the slot elements 41A and 41B are the same except that the main beam direction is different. Only the operation when the phase difference excitation of the 41B is performed will be described.

In this case, as described in the first embodiment, the excitation phase of the feeding unit 44A is delayed by about 50 degrees from the excitation phase of the feeding unit 44B, and the reverse bias is applied to the switching elements 43A and 43B. If so, the non-feeding elements 42C to 42D are not electrically connected. Therefore, the antenna characteristics are not affected, and the main beam tilted 60 degrees from the + Z direction to the + Y side is formed. Since the main polarization component at this time is the vertically polarization Eθ component, the slot elements 13A and 13B and the non-feeding elements 15A to 15D formed orthogonal to the main polarization may affect the antenna characteristics. Absent. When a forward bias is applied to the switching elements 43A and 43B, the non-feeding element 42A and the non-feeding element 42B, and the non-feeding element 42C and the non-feeding element 42D are connected to each other. Therefore, it becomes a linear element having a wavelength of about 0.54 and operates as a reflecting element. As a result, a main beam tilted 30 degrees from the + Z direction to the + Y side is formed. When the excitation phase of the feeding unit 44A advances by about 50 degrees with respect to the excitation phase of the feeding unit 44B, the main beam is formed in the direction tilted from the + Z direction to the -Y side.

FIG. 7 is a diagram showing the directivity of the antenna device shown in FIG. Here, FIG. 7A shows the directivity when a reverse bias is applied to the switching elements 16A and 16B or the switching elements 43A and 43B to form the main beam in the low elevation angle direction in which the elevation angle θ is 60 degrees. It is a figure. In the figure (A), the directivity e indicates the directivity of the conical surface when the excitation phase of the slot element 13A is delayed by about 50 degrees with respect to the excitation phase of the slot element 13B. It shows the directivity of the conical surface when the excitation phase of the slot element 13A advances by about 50 degrees with respect to the excitation phase of the slot element 13B. Further, the directivity g indicates the directivity of the conical surface when the excitation phase of the slot element 41A is delayed by about 50 degrees with respect to the excitation phase of the slot element 41B, and the directivity h indicates the excitation of the slot element 41A. It shows the directivity of the conical surface when the phase is advanced by about 50 degrees with respect to the excitation phase of the slot element 41B. All of these directional gains e to h have a directional gain of 12.3 dBi, a half-value angle of the conical surface pattern of 87 degrees, and a 4-sector antenna capable of covering all directions of the horizontal plane at an elevation angle of 60 degrees is formed.

On the other hand, FIG. 7B is a diagram showing the directivity when a forward bias is applied to the switching elements 16A and 16B or the switching elements 43A and 43B to form the main beam in the low elevation angle direction in which the elevation angle θ is 30 degrees. Is. Further, in FIG. 3C, the directivity i indicates the directivity of the conical surface when the excitation phase of the slot element 13A is delayed by about 50 degrees with respect to the excitation phase of the slot element 13B. Shows the directivity of the conical surface when the excitation phase of the slot element 13A advances by about 50 degrees with respect to the excitation phase of the slot element 13B. Further, the directivity k indicates the directivity of the conical surface when the excitation phase of the slot element 41A is delayed by about 50 degrees with respect to the excitation phase of the slot element 41B, and the directivity l indicates the excitation of the slot element 41A. It shows the directivity of the conical surface when the phase is advanced by about 50 degrees with respect to the excitation phase of the slot element 41B. All of these directional gains i to l have a directional gain of 9.4 dBi, a half-value angle of the conical surface pattern of 86 degrees, and a 4-sector antenna capable of covering all directions of the horizontal plane at an elevation angle of 30 degrees is formed.

As described above, according to the present embodiment, a sector antenna capable of covering all directions of the horizontal plane in the low elevation angle direction and the high elevation angle direction is formed. Therefore, as in the present embodiment, four slot elements are arranged in a square shape on the front surface of the substrate, and a plurality of linear non-feeding elements are formed on the back surface of the substrate in a direction orthogonal to the slot elements and face each other 2 A set of slot elements is selectively excited with a phase difference, and the linear non-feeding element is switched between connected and unconnected by a switching element to adjust the length, resulting in a compact, planar structure and a vertical surface. It is possible to realize a 4-direction multi-sector antenna that can switch the main beam direction.

[Third Embodiment] Next, the antenna device according to the third embodiment of the present invention will be described in detail with reference to the drawings. However, in the present embodiment, the same parts as those in the first embodiment shown in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted. In this embodiment as well, the operating frequency of the antenna will be described as 5 GHz. FIG. 8 shows the configuration of the antenna device according to the third embodiment of the present invention, which includes slot elements 51A to 51D, connecting conductors 52A to 52D, non-feeding elements 15A to 15D, and slot bypass elements 53A. , 53B and the power feeding unit 54 are provided on the copper foil layer 12 of the substrate 11.

The slot elements 51A to 51D are voids formed by cutting the copper foil layer 12, and are arranged in a square shape. The element length L4 is 16.3 mm (about 1/3 wavelength), and the element width is, for example, 1 mm. is there. Here, the non-feeding elements 15A to 15D are arranged on the line connecting the connection portions of the slot elements 51A and 51B and the connection portions of the slot elements 51C and 51D.

The connecting conductors 52A to 52D are formed on the same plane as the slot elements 51A to 51D by, for example, a copper foil pattern, and are slotted so as to divide the respective slot elements 51A to 51D at a position where the length L5 is about 5 mm. The inner copper foil layer and the outer copper foil layer of the element are connected. In this way, the impedance of the slot elements 51A to 51D can be stabilized by connecting the inner copper foil layer and the outer copper foil layer of the slot elements 51A to 51D with the connecting conductors 52A to 52D.

The slot bypass elements 53A and 53B are voids formed by cutting the copper foil layer 12 in the same manner as the slot elements 51A to 51D, and have a total length of 13 mm (about 1/4 wavelength) and a length of 6.5 mm (L6). It has a configuration that is folded back at about 1/8 wavelength). The element width is 1 mm. The slot bypass element 53A is connected between the slot element 51A and the slot element 51C, and the slot bypass element 53B is connected between the slot element 51B and the slot element 51D. The slot element 51A and the slot element 51B, and the slot element 51C and the slot element 51D are connected to each other, and here, the slot element is excited by the feeding unit 54 inserted between the slot element 51A and the slot element 51B. ..

Therefore, according to the present embodiment, with this configuration, the electric field takes a peak point at the connection portion of the slot elements 51A and 51B and the connection portion of the slot elements 51C and 51D, and the slot bypass element 53A , 53B causes a phase difference between the respective peak points. Therefore, if the radiation from these electric field peak points is simplified, it can be regarded as a configuration in which two slot antennas polarized in the X-axis direction are arranged in parallel. In this configuration, as described in the first embodiment, a main beam tilted from the + Z direction to the ± X direction is formed.

(I) FIG. 9 is a diagram showing the directivity of the antenna device shown in FIG. 8 when a reverse bias is applied to the switching elements 16A and 16B. In FIG. 9, (A) shows the directivity of the vertical (XZ) plane, and (B) shows the directivity of the conical surface at an elevation angle θ of 60 degrees. In FIG. 3A, the directivity m indicates the directivity of the vertically polarized wave Eθ component, and it can be confirmed that the main beam tilted in the direction of the elevation angle θ of 60 degrees is obtained. On the other hand, in FIG. 3B, the directivity n shows the directivity of the vertically polarized Eθ component as well as the directivity m, and it can be confirmed that the main beam is directed in the + X direction. At this time, the directivity gain of the main beam is 13.2 dBi, and the half-value angle of the conical surface pattern is 62 degrees.

(II) Next, FIG. 10 is a diagram showing the directivity of the antenna device shown in FIG. 8 when a forward bias is applied to the switching elements 16A and 16B. In FIG. 10, FIG. 10 (A) shows the directivity of the vertical (XZ) plane, and FIG. 10 (B) shows the directivity of the conical surface at an elevation angle θ of 20 degrees. In FIG. 10A, the directivity o indicates the directivity of the vertically polarized wave Eθ component, and it can be confirmed that the main beam tilted in the direction of the elevation angle θ of 20 degrees is obtained. Further, in FIG. 10 (B), the directivity p shows the directivity of the vertically polarized wave Eθ component as in the directivity o, and it can be confirmed that the main beam is directed in the + X direction. At this time, the directivity gain of the main beam is 8.9 dBi, and the half-value angle of the conical surface pattern is 84 degrees.

In this way, by adopting the configuration of the present embodiment as shown in FIG. 8, a main beam tilted to the + X side can be obtained, and the lengths of the non-feeding elements 15A to 15D are switched by the switching element to be vertical. The main beam direction can be switched between the high elevation angle direction and the low elevation angle direction in the (XZ) plane. Further, in the configuration shown in FIG. 8, the feeding portion 54 is provided only between the slot elements 51A and 51B, but the feeding portion is also provided between the slot elements 51C and 51D to selectively excite the device. The beam direction can be switched to ± X direction. At this time, it is necessary to open the power feeding unit that does not excite. Further, it is also possible to configure a sector antenna capable of covering all directions of the horizontal plane by arranging the ones having the configuration shown in FIG. 8 by rotating them at equal angles on a plurality of planes.

As described above, according to the antenna device of the present embodiment, the slot elements 51A to 51D formed in a square shape on the surface of the substrate 11 and the slot bypass elements 53A and 53B are provided at the opposite vertices of the square. , A plurality of linear non-feeding elements 15A to 15D are formed on the back surface of the substrate 11, and further, a reflecting plate 14 is provided at a certain distance from the slot elements 51A to 51D surfaces to provide linear non-feeding elements 51A to 51D. The length of 51D can be adjusted by switching between connected and unconnected with the switching elements 16A and 16B. Therefore, it is possible to realize a multi-beam antenna device that has a small size and a planar structure, can switch the main beam in the low elevation angle direction and the high elevation angle direction on a vertical plane, in other words, can transmit and receive a plurality of beams with one antenna. Can be done. In the present embodiment, the slot elements are arranged in a square shape, but the shape is not limited to the square shape, and may be a circular shape or a rhombus shape.

The present invention is not limited to the above-described embodiment, and can be implemented in various forms without departing from the gist thereof. For example, in the present invention, the inner copper foil layer and the outer copper foil layer of the slot element are connected in the same plane by a connecting conductor, but the same effect can be obtained even if they are connected on the back surface of the substrate through the through holes. Is obtained.

According to the present invention, a main beam having vertical polarization tilted in the horizontal direction can be formed in a low elevation angle direction and a high elevation angle direction, and the main beam direction can be switched in a horizontal plane. It has the effect of realizing a small multi-beam antenna with a suitable horizontal structure, and can be applied to small radios such as fixed radios and terminal radios.

<figref num="1">The configuration of the antenna device according to the first embodiment of the present invention is shown, (A) is a plan view, (B) is a side view, and (C) is a plan view seen from the back.</figref><figref num="2">An operation explanatory view when a reverse bias is applied to the switching element of the antenna device according to the first embodiment of the present invention.</figref><figref num="3">The figure which shows the directivity of the antenna device at that time</figref><figref num="4">An operation explanatory view when a forward bias is applied to the switching element of the antenna device according to the first embodiment of the present invention.</figref><figref num="5">The figure which shows the directivity of the antenna device at that time</figref><figref num="6">The configuration of the antenna device according to the second embodiment of the present invention is shown, (A) is a plan view, (B) is a side view, and (C) is a plan view seen from the back.</figref><figref num="7">The figure which shows the directivity when the forward bias is applied to any switching element of the antenna device which concerns on 2nd Embodiment of this invention.</figref><figref num="8">The configuration of the antenna device according to the third embodiment of the present invention is shown, (A) is a plan view, (B) is a side view, and (C) is a plan view seen from the back.</figref><figref num="9">The figure which shows the directivity when the reverse bias is applied to the switching element of the antenna device.</figref><figref num="10">The figure which shows the directivity when the forward bias is applied to the switching element of the antenna device.</figref><figref num="11">Top view showing the configuration of a conventional multi-sector antenna</figref><figref num="12">Top view showing the configuration of other conventional multi-sector antennas</figref>

Code description

11 (Dielectric) Substrate 12 Copper foil layer 13A, 13B Slot element 14 Reflector 15A ~ 15D Non-feeding element 16A, 16B Switching element 17A, 17B Feeding part 21A, 21B, 31A, 31B Point wave source 22A, 22B, 32A, 32B Image wave source a ~ p Directivity