JP2018182584A - Directivity-switching antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a directivity-switching antenna which enables switching between two characteristics, i.e., a high-gain, narrow directivity and a low-gain, wide directivity.SOLUTION: A directivity-switching antenna comprises: a first conductor 21 having an electric wave-radiation face formed by a flat conductor; a second conductor 22 spaced apart therefrom in a direction of a first axis on a first plane; a third conductor 23 having an electric wave-radiation face formed by a flat conductor, and spaced apart from the first conductor by a predetermined distance in a normal direction to the electric wave-radiation face of the first conductor in parallel therewith; and a fourth conductor 24 having the same shape as the third conductor, having an electric wave-radiation face on a second plane where the third conductor is disposed, and spaced apart from the third conductor in a direction in parallel with the first axis. The directivity-switching antenna further comprises: a first power-feeding/receiving line for unbalanced power feeding/receiving to/from the first and third conductors; a second power-feeding/receiving line for balanced power feeding/receiving to/from the first and second conductors and/or the third and fourth conductors; and a main switch for switching an electric line to transmit a transmitting/receiving signal between the first power-feeding/receiving line and the second power-feeding/receiving line.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a transmit / receive antenna that can switch the directivity of the antenna. In particular, the present invention relates to a transmitting or receiving antenna that can switch directivity in microwave power transmission.

  Conventionally, as an antenna for switching directivity, the technology disclosed in Patent Document 1 below is known. Four linear antennas are erected on the conductor in four directions, and directivity is controlled by switching the four antennas. Further, according to the technology disclosed in Patent Document 2 below, a first feeding element that generates a first polarization, a second feeding element that generates a second polarization, and a first generating a first polarization and a second polarization. And 3 feed elements. The directivity can be controlled by controlling the phase difference between the first polarization and the second polarization.

JP, 2013-201675, A JP, 2013-201496, A

  However, in the technology disclosed in Patent Document 1, only one of the four conductors is used at the time of antenna operation, so there is a problem that the total antenna size becomes large. Also, although this antenna can change directivity, it can not change gain. Further, in the technology disclosed in Patent Document 2, since the third feed element is always operating, the size of all the antennas is smaller than the size of the antenna disclosed in Patent Document 1, but the first feed element And the second feeding element operate independently, so they are not sufficiently miniaturized. This antenna may also change directivity but not gain.

  Therefore, an object of the present invention is to make it possible to change both directivity and gain without increasing the size of the antenna.

  According to the configuration of the invention for solving the above-mentioned problems, in the directivity switching antenna, the first conductor whose radio wave radiation / reception wavefront is a flat conductor, and the radio wave radiation / reception wavefront in the same shape as the first conductor A second conductor arranged on the first surface on which the radio wave radiation / reception wave front of one conductor is arranged and spaced apart in the first axial direction on the first plane, and the radio wave radiation / reception wave front being planar A third conductor which is made of a conductor and which is disposed in parallel at a predetermined distance in the normal direction of the radio wave emission / reception wave front of the first conductor, and a radio wave emission / reception wave front having the same shape as the third conductor On a second surface on which the second conductor is disposed, the fourth conductor being spaced apart in the direction parallel to the first axis, and the first power feeding for unbalanced power feeding / receiving on the first conductor and the third conductor / Feeding power receiving line for balanced power feeding / receiving on the power receiving line, the first conductor and the second conductor, and / or the third conductor and the fourth conductor And a main switch for switching the line for transmitting / receiving signals between the first feeding / receiving line and the second feeding / receiving line, controlling the main switch, and the main switch serving as the first feeding / receiving line When the first conductor and the second conductor are connected in series, the third conductor and the fourth conductor are connected in series to feed / receive power, and the main switch selects the second feed / receiving line The controller is characterized in that it has a controller for supplying / receiving power to / from the third conductor and the fourth conductor and / or supplying / receiving power to / from the first conductor and the second conductor.

The present invention is a high gain patch antenna having a narrow directivity in the normal direction of the radio wave radiation / received wave front of the first conductor and the second conductor, wherein the third conductor and the fourth conductor (or the first conductor and the second conductor) And a wide range directivity and low gain dipole antenna. Even with the same antenna, switching between the patch antenna and the dipole antenna makes it possible to use the antenna with high gain, narrow directivity, and low gain, wide directivity according to applications.
The antenna of the present invention can be used for both transmitting and receiving antennas. The radio wave radiation / reception wavefront is a radio wave radiation surface in the case of a transmission antenna and is a reception wavefront in the case of a reception antenna. The function as an antenna is the same. Further, the meaning of feeding / receiving, feeding / receiving line means feeding in the case of a transmitting antenna and feeding line in the case of a receiving antenna, and means receiving / receiving line in the case of a receiving antenna. Power supply and power reception are also identical in function, and only the signal flow direction is different.

In the present invention, the control device has a first switch that brings the first conductor and the second conductor into conduction or non-conduction, and a second switch that brings the third conductor and the fourth conductor into conduction or non-conduction. When the main switch selects the first feeding / receiving line, the first switch and the second switch are brought into conduction, and when the main switch selects the second feeding / receiving line, the first switch and the second It is desirable that the switch be in a nonconductive state. The position where the first switch and the second switch are provided is arbitrary, and this switch is included in the control device.
Furthermore, in the above, the control device includes a third switch that brings the first conductor and the third conductor into conduction or non-conduction, and a fourth switch that brings the second conductor and the fourth conductor into conduction or non-conduction When the main switch selects the first feeding / receiving line, the third switch and the fourth switch are brought out of conduction, and when the main switch selects the second feeding / receiving line, the third switch It is desirable that the fourth switch be in a conductive state. In the same manner as described above, the positions at which the third switch and the fourth switch are provided are arbitrary, and the switch is included as a control device.

  In the above invention, the dielectric substrate may be provided, and the first surface may be the surface of the dielectric substrate, and the second surface may be the back surface of the dielectric substrate. The first conductor to the fourth conductor may be disposed in the space, or the first conductor and the second conductor may be disposed on the thin first dielectric substrate, and the third conductor and the fourth conductor may be disposed in the thin fourth The first dielectric substrate and the second dielectric substrate may be disposed with a gap provided between the first and second dielectric substrates. By arranging the conductor plates on the front surface and the back surface of the substrate, the antenna can be easily handled.

  In addition, it is preferable that a balun that is unbalancedly fed / received to the main switch and a second feeding / receiving line be inserted to convert from unbalanced to balanced. That is, in the case of functioning as a dipole antenna, balanced feeding and balanced receiving are performed.

Also, the first conductor has a shape and size such that the orthographic projection of the first conductor onto the third conductor is contained within the outline of the third conductor, and the second conductor is on the fourth conductor. Desirably, the orthogonal projection of the second conductor has a shape and a size that is contained within the contour of the fourth conductor.
When functioning as a patch antenna, the third conductor and the fourth conductor can function as a reflector for radio waves. Since the third conductor and the fourth conductor include the orthogonal projections of the first conductor and the second conductor which radiate or receive waves, the radiation efficiency and the reception efficiency of the radio wave are enhanced.

The first conductor, the second conductor, the third conductor, and the fourth conductor have a rectangular shape, and the first long sides of the first conductor and the second conductor are positioned on the same straight line parallel to the first axis. Preferably, the second long sides of the third conductor and the fourth conductor are located on the same straight line parallel to the first axis, and the second long side is longer than the first long side.
The second long side of the third conductor and the second long side of the fourth conductor can effectively function as a dipole antenna.

  According to the present invention, it is possible to switch between two characteristics of high gain, narrow directivity and low gain and wide directivity with a simple structure without increasing the size of the antenna. Thus, one antenna can be used for two applications due to the difference in its characteristics.

The block diagram which showed the directivity switch antenna which concerns on one specific Example of this invention. The block diagram of the control apparatus of the Example. The block diagram of the directivity switching antenna which concerns on another Example. The block diagram of the directivity switching antenna which concerns on another Example. The characteristic view which shows the reflective characteristic of the directivity switching antenna which concerns on an Example. The Smith chart which showed the input impedance of the directivity switching antenna which concerns on an Example, and a reflection coefficient. Explanatory drawing which shows the usage example of the directivity switching antenna which concerns on an Example. Explanatory drawing which shows the other usage example of the directivity switching antenna which concerns on an Example.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the embodiments.

  The directivity switching antenna 1 of this embodiment can be used as a transmitting antenna as well as a receiving antenna. Since the function of operation is the same, in order to simplify the description, it will be described as a transmitting antenna. Therefore, the radio wave radiation / reception wavefront is described as a radio wave radiation surface, and the feeding / receiving line is referred to as a feeding line.

1. Arrangement Structure of Conductors FIG. 1 is a configuration diagram showing the entire directivity switching antenna 1 according to the present embodiment. A rectangular thin plate first conductor 21 and a second conductor 22 are disposed on the surface 10 a of the rectangular dielectric substrate 10. On the back surface 10b of the dielectric substrate 10, the third conductor 23 and the fourth conductor 24 of a rectangular thin plate are disposed. The first conductor 21 and the second conductor 22 have the same shape and the same size. The third conductor 23 and the fourth conductor have the same shape and the same size. The area of the radio wave emission surface of the third conductor 23 is larger than the area of the radio wave emission surface of the first conductor 21, and the area of the radio wave emission surface of the fourth conductor 24 is larger than the area of the radio wave emission surface of the second conductor 22. The radio wave radiation surface is a surface parallel to the front surface 10a and the back surface 10b. When the first conductor 21 is orthographically projected onto the third conductor 23, the orthographic projection is included within the outline of the third conductor 23. Similarly, when the second conductor 22 is orthographically projected onto the fourth conductor 24, the orthographic projection is included within the outline of the fourth conductor 24.

  The long side 21 a of the first conductor 21 and the long side 22 a of the second conductor 22 are located on the same straight line parallel to the x-axis which is the first axis direction. The long side 23a of the third conductor 23 and the long side 24a of the fourth conductor 24 are located on the same straight line parallel to the x-axis which is the first axis direction. The positions of the short side 21 b parallel to the y-axis direction perpendicular to the first axis on the surface 10 a of the first conductor 21 and the short side 23 b of the third conductor 23 in the x-axis direction are the same. The y-coordinates of the middle point of the short side 21b and the middle point of the short side 23b coincide with each other. Similarly, the positions of the short side 22 b of the second conductor 22 and the short side 24 b of the fourth conductor 24 in the x-axis direction are the same. The y-coordinates of the middle point of the short side 22b and the middle point of the short side 24b coincide with each other. The long side 23a is longer than the long side 21a, and the short side 23b is longer than the short side 21b. Similarly, the long side 24a is longer than the long side 22a, and the short side 24b is longer than the short side 22b.

2. Patch Antenna and Dipole Antenna The first conductor 21 and the second conductor 22 function as radiation elements of the patch antenna, and radio waves are radiated in a direction perpendicular to the radio wave radiation plane (z-axis perpendicular to the surface 10a of the substrate). The third conductor 23 and the fourth conductor 24 are connected to the ground to act as a reflector.
A pair of the third conductor 23 and the fourth conductor 24 acts as a dipole antenna. In particular, the long side 23a of the third conductor 23 and the long side 24a of the fourth conductor 24 serve as excitation sides. The long side 21 a of the first conductor 21 is shorter than the long side 23 a of the third conductor 23, and the long side 22 a of the second conductor 22 is shorter than the long side 24 a of the fourth conductor 24. Therefore, the longer side 23a and the longer side 24a substantially function as a dipole antenna.

3. Arrangement of Feeding Line A control line for switching the feeding line and the feeding path is focused on the controller 40 disposed on the surface 10 a of the substrate 10.
(1) The first feed line acting as a patch antenna The live line L1 of the first feed line of unbalanced feeding is disposed from the outer short side of the first conductor 21 to the port of the control device 40 on the surface 10a. A ground line G of a first feeder extending from the outer short side of the third conductor 23 to the port of the control device 40 is disposed on the back surface 10b. Ground line G is drawn to surface 10a through the through hole. Further, a first switch SW1 for serially connecting the first conductor 21 and the second conductor 22 in the long side direction is disposed on the surface 10a of the substrate 10, and the third conductor 23 and the fourth conductor 22 are long sides. A second switch SW2 for series connection in the direction is disposed on the back surface 10b. A control line C1 for controlling the first switch SW1 on and off and a control line C2 for controlling the second switch SW2 on and off are wired up to the port of the control device 40.

(2) Second Feeding Wire Acting as a Dipole Antenna As a dipole antenna, balanced feeding may be performed to the third conductor 23 and the fourth conductor 24 having the longer side. Therefore, A line L2 which is one of the 2nd feeders from the middle point of inner short side 23b of the 3rd conductor 23 to control device 40 is arranged on back surface 10b and control hole 40 on front surface 10a to control device 40. It is set up. In addition, the B line L3 which is the other of the second feed line from the middle point of the inner short side 24b of the fourth conductor 24 to the control device 40 reaches the control device 40 on the back surface 10b and the surface 10a through the through holes. It is arranged.

4. Switching Control (1) Configuration of Control Device As shown in FIG. 2, the control device 40 has a main line 50 which is an unbalanced feed line, a first feed line 51 which is an unbalanced feed line, and a second which is a balanced feed line. A main switch MS is provided to switch the feed line 52. The second feed line 52 is provided with a balun 53 for converting from unbalanced to balanced.

(2) Selection of Patch Antenna In order to electrically connect the switch SW1 and the switch SW2, an H level signal is sent out to the control line C1 and the control line C2. As a result, the first conductor 21 and the second conductor 22 are connected in series in the long side direction. The third conductor 23 and the fourth conductor 24 are also connected in series in the long side direction. Next, the main switch MS is in a state of connecting the main line 50 and the first feed line 51. As a result, unbalanced power is supplied to the series connection of the first conductor 21 and the second conductor 22 and the series connection of the third conductor 23 and the fourth conductor 24. As a result, a patch antenna having directivity in the direction (z-axis direction) perpendicular to the radio wave radiation surface of the first conductor 21 and the second conductor 22 is obtained. The resonant frequency can be determined by the distance between the outer short side of the first conductor 21 and the outer short side of the second conductor 22. The third conductor 23 and the fourth conductor 24 connected to the ground function as a reflector that reflects radio waves radiated from the back surfaces of the first conductor 21 and the second conductor 22 to the surface 10 a side.

(3) Selection of Dipole Antenna In order to make the switch SW1 and the switch SW2 nonconductive, an L level signal is sent out to the control line C1 and the control line C2. The switch SW1 and the switch SW2 in FIG. 1 show a state in which they are operated as a dipole antenna. Thereby, the first conductor 21 and the second conductor 22 are insulated and separated. Similarly, the third conductor 23 and the fourth conductor 24 are also insulated and separated. Next, the main switch MS is in a state of connecting the main line 50 and the second feed line 52. Thus, the third conductor 23 is fed from the inner short side 23b through the A line L2 of the balanced feed line, and the fourth conductor 24 is fed from the inner short side 24b through the B line L3 of the balanced feed line. As a result, the third conductor 23 and the fourth conductor 24 are excited with both inner short sides 23 b and 24 b as excitation points. The resonant frequency can be determined by the distance between the outer short side of the third conductor 23 and the outer short side of the fourth conductor 24. The switches SW1 and SW2 can be formed of any switches such as transistors and relays.

1. Configuration In the configuration shown in FIG. 1, when the dipole antenna is configured, when the first conductor 21 and the second conductor 22 have a relatively large area, the first conductor 21 and the second conductor 22 function as a dipole antenna. The radiation from the third conductor 23 and the fourth conductor 24 may be affected. Therefore, as shown in FIG. 3 and FIG. 4, the control device is provided with a third switch SW3 for making the first conductor 21 and the third conductor 23 conductive and nonconductive in the z direction, and a control line C3 for controlling the switch on and off. You may wire up to 40. Similarly, a fourth switch SW4 for electrically connecting and disconnecting the second conductor 22 and the fourth conductor 24 in the z direction and a control line C4 for on / off controlling the switch may be connected to the control device 40. Then, from the inner short side 21 b of the first conductor 21 and the inner short side 22 b of the second conductor 22, one A-line L 4 and the other B-line L 5 of the second feed line for balanced feeding are controlled. Wire up to device 40. In this case, the A line L2 and the B line L3 for independently exciting the third conductor 23 and the fourth conductor in FIG. 1 become unnecessary.

2. Selection of Patch Antenna The operation of the control device 40 is the same as that of the first embodiment. That is, as shown in FIG. 3, the switch SW1 and the switch SW2 are brought into conduction, and the switch SW3 and the switch SW4 are brought out of conduction.

3. Selection of Dipole Antenna The main switch MS of the control device 40 is switched to the side of the second feed line 52 of the balanced feed line. Then, as shown in FIG. 4, the first switch SW1 and the second switch SW2 are brought out of conduction by the control lines C1 and C2. The third switch SW3 and the fourth switch SW4 are brought into conduction by the control lines C3 and C4. As a result, two groups of the first conductor 21 and the third conductor 23 and the second conductor 22 and the fourth conductor 24 are balancedly fed. These pairs will function as a dipole antenna.

[Gain and directional characteristics]
1. When a patch antenna is selected A directivity of 148.2 ° in beam width centered on the normal direction of the radio wave radiation surface of the first conductor 21 and the second conductor 22 is obtained. The gain in the normal direction was 5.15 dBi. The resonant frequency can be changed by the length of the long side 21 a of the first conductor 21 and the long side 22 a of the second conductor 22.

2. When a dipole antenna is selected: 360 ° in all directions from the normal direction (+ z axis direction) of the first conductor 21 and the second conductor 22 to the normal direction (−z axis direction) of the third conductor 23 and the fourth conductor 24 The directivity of the beam width was obtained. The gain in the + z axis direction was 2.048 dBi, and the gain in the −z axis direction was 1.7 dBi. In this case, the resonance frequency can be changed by the lengths of the long side 23 a of the third conductor 23 and the long side 24 a of the fourth conductor 24.

3. Independent control of resonant frequency The resonant frequency of the patch antenna can be controlled by the length of the long side 21 a of the first conductor 21 and the long side 22 a of the second conductor 22, and the resonant frequency of the dipole antenna is the length of the third conductor 23. It can be controlled independently by the length of the side 23 a and the long side 24 a of the fourth conductor 24. The reflection characteristics are shown in FIG. It can be seen that different resonance frequencies of 2.54 GHz for the patch antenna and 2.6 GHz for the dipole antenna are obtained. Also, the input impedance is shown in FIG. The input impedances of the patch antenna and the dipole antenna can be made equal at each resonance frequency.

[Example of use]
A usage example of the directivity switching antenna of this embodiment is shown in FIG. The antenna 1 is provided in the vehicle cabin. When the antenna 1 is used as a patch antenna, an electronic device such as a mobile phone can be installed in the normal direction of the surface 10 a of the substrate 10 to charge it. As a result, the mobile phone can be efficiently charged by microwave power transmission using the high gain and narrow directivity of the patch antenna. Moreover, it is assumed that electronic devices and sensors, such as RF-ID, are provided in the wide periphery in a vehicle interior. In this case, power transmission and information exchange can be performed on these electronic devices by utilizing the wide directivity of the dipole antenna in all directions.

  Further, as shown in FIG. 8, two antennas 1 of the present embodiment are provided in the x-axis direction, and two antennas 1 'of the present embodiment are provided in the y-axis direction orthogonal to this. This makes it possible to radiate and receive circularly polarized electromagnetic waves.

  The positions where the switches SW1 and SW2 in the first embodiment and the switches SW1, SW2, SW3 and SW4 in the second embodiment are provided are arbitrary. For example, lead wires may be provided from both ends of the switch to the region where the main switch MS of the control device 40 is disposed, and each switch may be provided in that region.

  The present invention can switch between a high gain narrow directivity patch antenna and a low gain wide directivity dipole antenna, and can be used for various power transmission and communication.

DESCRIPTION OF SYMBOLS 1 ... Dielectric substrate 21 ... 1st conductor 22 ... 2nd conductor 23 ... 3rd conductor 24 ... 4th conductor 40 ... Control apparatus MS ... Main switch L1, G, 51 ... 1st electric power feeding line L2, L3, L4, L5 ... Second feed line C1, C2, C3, C4 ... Control line

Claims (7)

In the directivity switching antenna,
A first conductor in which the radio wave radiation / wave receiving surface comprises a planar conductor;
The radio wave emission / reception wave front has the same shape as that of the first conductor on the first surface on which the radio wave emission / reception wave front of the first conductor is disposed, and is separated in the first axial direction on the first surface A second conductor placed
Radio wave radiation / wave receiving surface comprises a planar conductor, and a third conductor disposed in parallel at a predetermined distance in the normal direction of the wave radiation / wave receiving surface of the first conductor;
A fourth conductor having the same shape as the third conductor and arranged so that radio wave radiation / reception wavefronts are spaced apart in a direction parallel to the first axis on the second surface on which the third conductor is disposed; ,
A first power supply / reception line for unbalanced power supply / reception to the first conductor and the third conductor;
A second feeding / receiving line for performing balanced feeding / receiving on the first conductor and the second conductor and / or the third conductor and the fourth conductor;
A main switch that switches a line for transmitting / receiving signals between the first feeding / receiving line and the second feeding / receiving line;
When controlling the main switch and when the main switch selects the first feeding / receiving line, the first conductor and the second conductor are connected in series, and the third conductor and the fourth conductor are connected. When power is supplied / received in series connection and the main switch selects the second power supply / reception line, power is supplied / received to the third conductor and the fourth conductor or / and the first conductor and the first What is claimed is: 1. A directivity switching antenna comprising: a control device for feeding / receiving power to / from two conductors. The control device includes: a first switch that brings the first conductor and the second conductor into conduction or non-conduction; and a second switch that brings the third conductor and the fourth conductor into conduction or non-conduction Have
When the main switch selects the first feeding / receiving line, the first switch and the second switch are brought into conduction, and when the main switch selects the second feeding / receiving line, the first switch The directivity switching antenna according to claim 1, wherein the second switch is in a non-conductive state. The control device includes a third switch for electrically connecting or disconnecting the first conductor and the third conductor, and a fourth switch for electrically connecting or non-conducting the second conductor and the fourth conductor. Have
When the main switch selects the first power feeding / receiving line, the third switch and the fourth switch are brought out of conduction, and when the main switch selects the second power feeding / receiving line, the third switch is selected. The directivity switching antenna according to claim 2, characterized in that the switch and the fourth switch are brought into conduction.   4. The dielectric substrate according to claim 1, wherein the first surface is a surface of the dielectric substrate, and the second surface is a back surface of the dielectric substrate. Directivity switching antenna described.   5. A balun that is unbalancedly fed / received to the main switch and inserted into the second feeding / receiving line to convert from unbalanced to balanced is inserted in any one of claims 1 to 4. The directivity switching antenna according to item 1. The first conductor has a shape and size such that an orthographic projection of the first conductor onto the third conductor is contained within the outline of the third conductor,
The second conductor has a shape and a size in which an orthographic projection of the second conductor onto the fourth conductor is included in an outline of the fourth conductor. The directivity switching antenna according to any one of Items 5 to 5.   The first conductor, the second conductor, the third conductor, and the fourth conductor have a rectangular shape, and respective first long sides of the first conductor and the second conductor are parallel to the first axis. The second long sides of the third conductor and the fourth conductor are located on the same straight line, and the second long sides are located on the same straight line parallel to the first axis, and the second long side is greater than the first long side. The directivity switching antenna according to any one of claims 1 to 6, which is long.