JP2015043526A - Antenna apparatus and electromagnetic wave energy recovery apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna apparatus capable of simultaneously receiving and transmitting electromagnetic waves of different polarization and different frequencies.SOLUTION: An antenna apparatus 1000 includes: a reflection plate 100 of an EBG structure; a rectangular loop antenna 11 for a horizontal polarization; and a rectangular loop antenna 12 for a vertical polarization. The reflection plate 100 of an EBG structure is constituted of a metal ground plate 102 and rectangular metal patches 104 periodically arranged at a predetermined height from the ground plate.

Description

  The present invention relates to an antenna device for transmitting and receiving a plurality of types of radio waves and a configuration of an electromagnetic wave energy recovery device using the antenna device.

  In recent years, a system has been proposed in which radio wave energy existing in a living space (for example, TV broadcast radio wave, mobile phone base station radio wave, etc.) is collected and converted into DC power for reuse (for example, Patent Documents). 1, Non-patent document 1, Non-patent document 2). Such a system is also called an “energy harvester”.

  Recoverable power is weak compared to other energy sources such as sunlight and wind power, and may be a relatively stable power source regardless of day or night, weather, etc. It is thought that it can contribute to.

  Since the energy of radio waves existing in a general living space is very weak, in order to obtain as much power as possible, it is required to simultaneously capture radio waves of a plurality of frequencies and combine them with DC power. In particular, terrestrial digital television broadcast radio waves and mobile phone base station radio waves are powerful collection target frequencies. Digital terrestrial television broadcast radio waves are mainly horizontally polarized waves, and mobile phone base station radio waves are mainly vertically polarized waves.

  On the other hand, an artificial structure called an electromagnetic band-gap (EBG) is known. The EBG has a structure in which unit structures smaller than the wavelength are periodically arranged. In the unit structure, a metal patch is formed on the surface of the substrate, a ground plane is formed on the back surface of the substrate, and a short-circuit pin that short-circuits the patch and the ground plane is provided through the substrate. An EBG having such a structure resonates at a specific frequency, and has a property that the reflected wave phase is + 0 ° (in-phase reflection) at the resonance frequency. In addition, since electromagnetic waves do not propagate through the EBG structure at this resonance frequency, an antenna that uses this EBG structure as a reflector and suppresses backward radiation has been proposed (Patent Document 2). ).

  In addition, since an antenna using a reflector having an EBG structure becomes a narrow band, it is possible to change the resonance frequency of the EBG structure by providing a variable varicap between adjacent patches in the EBG structure. This is proposed in Patent Document 3.

  FIG. 16 is a diagram showing the structure of an antenna using a reflector having an EBG structure disclosed in Patent Document 3. As shown in FIG.

  The antenna disclosed in Patent Document 3 is a circularly polarized broadband spiral antenna, and by changing the voltage applied to the varicap in the EBG structure, the resonance frequency of the EBG structure is changed, and radio waves of various frequencies ( For example, it becomes possible to cope with digital terrestrial television, mobile phone, GPS) as necessary.

  FIG. 17 is a diagram showing a unit structure of the EBG structure shown in FIG.

  By making the unit structure a rectangle as shown in FIG. 21, an EBG structure having polarization dependency can be obtained. As a result, the reflection phase is 0 ° in a certain polarization direction, but the reflection phase is far away from 0 ° in the polarization direction orthogonal thereto, and the reflection phase is 0 ° in the circular polarization transmitted from the spiral antenna. Only the linearly polarized wave in the direction is transmitted. By changing the capacity of the varicap, it is possible to transmit only orthogonal polarized waves (transmission and reception are reversible according to the reciprocity theorem, and thus operate similarly as a reception antenna).

Special table 2008-544730 JP 2009-100445 A JP 2009-033324 A

Shoichi Kitazawa, Hirokazu Kamoda, Norihiro Hanazawa, Susumu Ano, Koji Ban, Kiyoshi Kobayashi, “Examination of electromagnetic energy recovery for broadcasting and communication radio waves,” IEICE Tech. Bulletin, MW2012-143, pp.5− 10, 2013. Hirokazu Kamoda, Norihiro Hanazawa, Shoichi Kitazawa, Hiroshi Ban, Kiyoshi Kobayashi, “Fundamental study of rectenna array configuration for electromagnetic energy recovery considering mutual coupling,” IEICE Tech. Bulletin, MW2013-20, pp.59-64, 2013.

  When an antenna device using such an EBG structure as a reflector is to be applied to the above-described energy harvester, there are the following problems.

  That is, the antenna device disclosed in Patent Document 3 can variably perform transmission / reception of a plurality of types (frequency, polarization) of radio waves, but at the same time receive (transmit) two or more types of radio waves. Can not. For example, if two antennas of Patent Document 3 are arranged side by side or two types of antennas operating at different polarizations and frequencies are arranged next to each other, two types of radio waves can be received (transmitted) simultaneously. In this case, the entire antenna becomes large and a large installation space is required. From the aspect of radio wave energy recovery, the recovered power per unit area is reduced.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide an antenna device that can simultaneously receive (transmit) radio waves of different frequencies with different polarizations. is there.

  Another object of the present invention is to provide an antenna device having a low attitude and a small physical area of the antenna.

  Another object of the present invention is to provide an electromagnetic wave energy recovery device capable of simultaneously receiving radio waves of different frequencies with different polarizations and recovering energy.

  Another object of the present invention is to provide an electromagnetic wave energy recovery device capable of making a space for installation compact by using an antenna device having a low attitude and a small physical area of the antenna.

  According to one aspect of the present invention, in the antenna device, the first antenna element for horizontal polarization and the first antenna element are arranged so as to share a central position, and the first antenna element for vertical polarization is used. Two antenna elements and a reflector having an electromagnetic bandgap structure provided on the back side of the first and second antenna elements, the reflector having a predetermined height from the conductive ground layer and the ground layer. And a plurality of rectangular conductive patches arranged periodically.

  Preferably, at least a part of the first antenna element is parallel to one of the short side and the long side of the rectangle, and at least a part of the second antenna element is the other of the short side and the long side of the rectangle. And parallel.

  Preferably, the horizontal dimension of each rectangular conductive patch is set in accordance with the frequency of the horizontally polarized wave of the target electromagnetic wave, and the vertical dimension of each rectangular conductive patch is the target electromagnetic wave. Is set corresponding to the frequency of the vertically polarized wave.

  Preferably, the first antenna element and the second antenna element are rectangular loop antennas arranged concentrically and having different dimensions.

  Preferably, the first antenna element and the second antenna element are dipole antennas that are arranged to be orthogonal to a common center and have different dimensions.

  According to another aspect of the present invention, there is provided an electromagnetic wave energy recovery device comprising a plurality of antenna devices, wherein the antenna device has a center position between the first antenna element for horizontal polarization and the first antenna element. A second antenna element for vertical polarization and a reflector having an electromagnetic bandgap structure provided on the back surfaces of the first and second antenna elements, the reflector being conductive And a plurality of rectangular conductive patches periodically arranged at a predetermined height from the ground layer, and a power combining device for combining the power from each antenna device.

  Preferably, the power combiner includes a first rectifier circuit provided in the power feeding unit of the first antenna element, a second rectifier circuit provided in the power feeding unit of the second antenna element, and the first and second And a direct current combining circuit for combining direct current power from the rectifier circuit.

  Preferably, the reflecting plate is provided in common to the plurality of first antenna elements and the plurality of second antenna elements.

  According to the antenna device of the present invention, radio waves having two frequencies with different polarizations can be transmitted (received) simultaneously. For this reason, in the electromagnetic wave energy recovery apparatus using this, electric power can be recovered more efficiently.

  Moreover, according to the antenna device of the present invention, an antenna can be realized with a smaller area than in the prior art. For this reason, in the electromagnetic wave energy recovery apparatus using this, if it is the same area, more electric power can be collect | recovered than the conventional system.

FIG. 3 is a perspective view of the antenna device 1000 according to the first embodiment on an elevation surface. It is a perspective view from the side of antenna device 1000. It is the upper side figure and side view of the antenna apparatus 1000. It is a figure for demonstrating the gain of the antenna when not providing the reflecting plate of an EBG structure. 2 is a functional block diagram for explaining a configuration of an energy harvester (electromagnetic energy recovery device) 2000. FIG. It is a figure for demonstrating the layer structure of an EBG reflector. It is a figure which shows the unit structure of EBG. It is a figure which shows the frequency characteristic of the reflection phase in the dimension of the unit structure of EBG. It is a figure which shows the dimension of the square loop antennas 11 and 12. FIG. It is a figure which shows an antenna reflection coefficient. It is a figure which shows the radiation pattern of the loop antenna 11 (horizontal polarization: 500 MHz). It is a figure which shows the radiation pattern of the loop antenna 12 (vertically polarized wave: 840 MHz). It is a figure for demonstrating the structure of antenna apparatus 1000 'of Embodiment 2 of this invention. It is a figure for demonstrating the structure of antenna apparatus 1000 '' of Embodiment 3 of this invention. It is a figure for demonstrating the structure of the antenna apparatus 1002 in the case of using a dipole antenna. It is a figure which shows the structure of the antenna using the reflecting plate of the EBG structure disclosed by patent document 3. FIG. It is a figure which shows the unit structure of the EBG structure shown in FIG.

  Hereinafter, an antenna device according to an embodiment of the present invention will be described with reference to the drawings. In the following embodiments, components and processing steps given the same reference numerals are the same or equivalent, and the description thereof will not be repeated unless necessary.

  As described below, the antenna device according to the present embodiment includes a reflector having an electromagnetic bandgap structure, and transmits and receives a plurality of radio waves having different polarizations and different frequencies.

Below, the case where the antenna apparatus of this Embodiment is used as an energy harvester is demonstrated as an example. However, the antenna device can be used not only for reception as in the case of use as an energy harvester but also for transmission.
(Embodiment 1)
FIG. 1 is a perspective view of the antenna device 1000 according to Embodiment 1 in an elevational view.

  FIG. 2 is a perspective view from the side of the antenna device 1000.

  3 is a top view and a side view of the antenna device 1000, FIG. 3 (a) is a top view, and FIG. 3 (b) is a side sectional view.

  When the antenna device 1000 is used as a energy harvester, for example, it is installed on a side wall surface of a building, a side wall surface of an indoor room, or the like.

  Referring to FIGS. 1 and 2, an antenna device 1000 includes a reflector 100 having an EBG structure, a horizontally polarized square loop antenna 11 and a vertically polarized square loop antenna 12 arranged on the front side thereof. With.

  In practice, a dielectric spacer plate for physically supporting the square loop antenna 11 and the square loop antenna 12 is provided between the reflector 100 and the square loop antenna 11 and the square loop antenna 12. However, in the drawing, such a dielectric spacer plate is not shown in order to simplify explanation such as making the structure easy to see.

  As the dielectric spacer plate, a non-conductive material having a predetermined dielectric constant defined by the frequency of the target radio wave is used. In general, it is desirable that the dielectric constant is small, for example, polystyrene foam. Etc. may be used.

  Referring to FIG. 3, a reflector 100 having an EBG structure includes a ground plate 102 made of a conductive material (for example, metal), and patches 104 of the conductive material periodically arranged at a predetermined height from the ground plate. (Hereinafter, as an example, let us consider the case of being formed of so-called metal, which is referred to as a metal patch. When a plurality of metal patches 104.1 to 104.n are collectively referred to as “metal patch 104”) Composed. Moreover, each metal patch 104.1-104. n has a rectangular shape when viewed from above.

  In general, an EBG structure can be manufactured by using a single printed board 106 and providing a ground plate 102 on the back side and a metal patch 104 on the front side. On the EBG reflector, a horizontally polarized square loop antenna 11 and a vertically polarized square loop antenna 12 are arranged. The two loop antennas are arranged concentrically.

  A square loop antenna or a metal patch can be formed of a printed circuit board. In consideration of high-frequency characteristics, for example, a Teflon (registered trademark) substrate, an alumina (ceramics) substrate, a low-temperature co-fired ceramic substrate, or the like is used. it can. As described above, as the metal ground plate 102, as an example, a ground layer on the back surface of the printed board on which the metal patch is formed can be used. When an EBG structure is created by a method other than the method used, for example, a metal plate such as an aluminum plate can be used as the ground plate.

  The period of the periodic structure of the EBG reflector is set to be sufficiently smaller than the wavelength. For example, this period is about 1/10 wavelength. The arrangement height of the square loop antennas 11 and 12 from the patch surface is sufficiently smaller than a quarter wavelength, for example, about 2/100 wavelengths.

  Rectangular metal patch 104.1-104. The dimension of n in the horizontal direction (x direction) is determined by the frequency of horizontal polarization to be received (transmitted), and the dimension in the vertical direction (y direction) is the frequency of vertical polarization to be received (transmitted). Determined by. In other words, rectangular metal patches 104.1-104. Since n has a rectangular shape, it can be configured to have different frequency characteristics in the short side direction and the long side direction. Therefore, an antenna device that simultaneously receives electromagnetic waves having different frequencies for horizontal polarization and vertical polarization respectively. It becomes possible.

An antenna that rectifies and converts microwave energy into a direct current is also called a rectenna (rectifying antenna).
(Reason for providing a reflector with an EBG structure)
FIG. 4 is a diagram for explaining the gain of the antenna when a reflector having an EBG structure is not provided.

  Consider a case where a loop antenna is used as an energy harvester.

  A rectenna array panel is a rectenna array panel that has a plurality of loop antennas with different reception frequencies arranged on the same dielectric substrate, and is configured to receive multiple frequencies in the same space efficiently while being thin. Call.

  The loop antenna is suitable for transmission / reception of a relatively low frequency such as terrestrial digital broadcast waves and mobile phone base station radio waves. However, simply using a loop antenna or a rectenna array panel using the loop antenna, when placed near a metal or concrete wall, power can be efficiently recovered due to the effects of changes in alignment and loss of wall materials. It is expected not to be possible.

  4A shows a state where the loop antenna 11 is installed in the vicinity of the metal or concrete wall 10, and FIG. 4B shows the operating gain (E surface) of the loop antenna at 500 MHz.

  Compared with the case where the loop antenna 11 is arranged in free space, the decrease in the maximum gain is as large as 3 dB when the concrete is close and 4.6 dB when the metal plate is used. Efficiency has also decreased to 33% and 7%, respectively. The effect of the wall can be eliminated by placing the conductor reflector at a position that is 1/4 wavelength away from the antenna on the wall side. However, a thickness corresponding to 1/4 wavelength is required, and multiple frequencies can be used. It is difficult to respond.

Therefore, as described above, in the present embodiment, a reflector having an EBG structure is provided on the back surface of the loop antenna.
(Configuration of energy harvester)
FIG. 5 is a functional block diagram for explaining the configuration of the energy harvester (electromagnetic energy recovery device) 2000.

  Referring to FIG. 5, the electromagnetic energy recovery apparatus 2000 according to the embodiment of the present invention includes a plurality of antennas 200, a plurality of rectifying units 202, a combining unit 204, and an output unit 206. The plurality of antennas 200 are arranged at predetermined positions to constitute an array antenna. As the array antenna, a rectenna antenna may be individually installed on a wall surface, or a rectenna array panel having an integral structure as described above.

  Each of the plurality of antennas 200 corresponds to the loop antenna 11 or 12 described above. That is, the electromagnetic wave energy recovery apparatus 2000 is provided with a plurality of sets of loop antennas 11 and 12.

  Each rectification unit 202 is connected in the vicinity of each antenna 200 and converts (rectifies) an alternating voltage generated by the interaction between the antenna 200 and the electromagnetic wave into a direct voltage. A known technique may be used for the rectification, and the rectification unit can be realized by a known circuit.

  The combining unit 204 combines the DC power (DC voltage or DC current) output from the rectifying unit 202. The interconnection of the plurality of rectifying units 202 may be a series connection, a parallel connection, or a connection in which a series connection and a parallel connection are mixed. In the case of alternating current (especially in the case of high frequency), it is affected by the wiring pattern, but since the output of the rectifier 202 is direct current, it is hardly affected by the wiring pattern and arbitrary wiring is possible.

The output unit 206 converts the output power of the combining unit 204 into a voltage or current corresponding to the target load 208 and supplies the converted voltage or current to the load 208. The output unit 206 may be a circuit for supplying a voltage and current according to the target load 208, and may be configured by a known voltage conversion circuit and current conversion circuit. The output unit 206 may include a power storage device such as a capacitor or a secondary battery.
(Design procedure for antenna device)
(Design of EBG unit structure)
A specific procedure for determining the unit structure of EBG will be described below.

  1) First, a computer model of the unit structure is created, and the frequency characteristic of the reflection phase is obtained for each of the polarization in the x direction and the polarization in the y direction (this method is well known to those skilled in the art and is omitted). To do). At this time, the relative dielectric constant of the material actually used is set as the relative dielectric constant of the substrate.

  2) The thickness of the substrate, the size of the metal patch, and the period are determined so that the reflection phase has a predetermined value at a desired frequency in each polarization. Here, the predetermined value may be 30 °, for example. How much this value is set can be found by, for example, parametric analysis by electromagnetic field simulation. Note that the greater the size of the rectangular patch, the greater the period, and the greater the thickness, the lower the resonance frequency of the EBG structure (the frequency at which the reflection phase becomes 0 °).

(Design of square loop antenna)
A method for determining the dimensions of the rectangular loop antenna will be described below.

  1) The width of the loop antenna is, for example, about 1/100 wavelength. The length of one side of the loop is provisionally determined to be around 1/4 of the wavelength of the desired frequency.

  2) First, only the loop antenna 11 is arranged, and the structure of FIG. 3 is modeled on a computer. Since it is horizontally polarized, the feeding point is at the center of the side parallel to the x-axis. The frequency characteristic of the antenna reflection coefficient at the feeding point is obtained by electromagnetic field simulation. The frequency characteristic of the antenna reflection coefficient is obtained while changing the length of one side of the loop. Then, the length of one side of the loop when the antenna reflection coefficient is minimized at the design frequency for the horizontally polarized wave is determined as the length of one side of the loop of the loop antenna 11.

  3) Next, the loop antenna 12 is added, and the length of one side of the loop antenna 12 is determined so that the antenna reflection coefficient is minimized at the design frequency for vertical polarization. Since the loop antenna 12 is vertically polarized, the feeding point is provided at the center of the side parallel to the y axis.

(Specific examples of design)
More specifically, a specific example of the design of this antenna when the design frequency is 500 MHz for horizontal polarization and 840 MHz for vertical polarization is shown below.

  First, FIG. 6 is a diagram for explaining the layer structure of the EBG reflector.

  Referring to FIG. 6, in the layer structure of the EBG reflector, a dielectric spacer having a relative dielectric constant of approximately 1.0 is used to ensure thickness, and a relative dielectric constant of 9 having a rectangular metal patch on one side. Supports 8 printed circuit boards. Furthermore, a dielectric substrate having a relative dielectric constant of approximately 1.0 is used to support a printed circuit board having a relative dielectric constant of 3.7 having the loop antennas 11 and 12.

  FIG. 7 is a diagram showing a unit structure of EBG.

  FIG. 7A is a top view, and FIG. 7B is a side sectional view.

  FIG. 8 is a diagram showing the frequency characteristics of the reflection phase at the dimensions of the unit structure of the EBG shown in FIG.

  The horizontal polarization has a frequency of 500 MHz, the vertical polarization has a frequency of 840 MHz, and the reflection phase is about 30 °. This unit structure was arranged in a unit of 10 units in the horizontal direction (x direction) and 25 units in the vertical direction (y direction) to form an EBG structure reflector.

  FIG. 9 is a diagram showing the dimensions of the square loop antennas 11 and 12.

  In the loop antenna 11, in consideration of horizontal polarization, the power feeding unit is provided on a side parallel to the x axis, the thickness of the antenna is 5 mm, and the length of one side is 120 mm.

  In the loop antenna 12, in consideration of vertical polarization, the power feeding unit is provided on a side parallel to the y axis, the thickness of the antenna is 5 mm, and the length of one side is 80 mm.

  FIG. 10 is a diagram showing the antenna reflection coefficient in the above configuration.

  FIG. 10 shows that the reflection coefficient is reduced to −10 dB or less at a desired frequency, so that reception (transmission) can be performed efficiently.

  FIG. 11 is a diagram showing a radiation pattern of the loop antenna 11 (horizontal polarization: 500 MHz).

  FIG. 12 is a diagram showing a radiation pattern of the loop antenna 12 (vertically polarized wave: 840 MHz).

  11 and 12, the maximum gain is 8.9 dBi and 10.6 dBi, respectively, which is higher than the gain of about 3 dBi of a single loop antenna that does not use the EBG structure, and the maximum gain direction is not disturbed. It can be seen that it is maintained almost in the front direction (+ z direction).

From the above, it can be seen that a low-profile antenna capable of efficiently receiving (transmitting) each polarized wave (frequency) simultaneously can be realized. In addition, since the two loop antennas are arranged concentrically, the size of the entire antenna can be kept small.
(Embodiment 2)
FIG. 13 is a diagram for explaining the configuration of the antenna device 1000 ′ according to the second embodiment of the present invention.

  The antenna device 1000 ′ of the second embodiment is different from the structure of the antenna device 1000 of the first embodiment in that rectifier circuits 202H and 202V for converting received radio waves into direct current are provided on a dielectric spacer plate and are antennas. It differs in the point which set it as the structure provided in the position of the electric power feeding point on the board | substrate (for example, printed circuit board) which forms.

  That is, as shown in FIG. 13, a rectifier circuit 202 </ b> H is provided in the power feeding part of the square loop antenna 11, and a rectifier circuit 202 </ b> V is provided in the power feeding part of the square loop antenna 12. By providing the rectifier circuits 202H and 202V, it becomes possible to efficiently convert to a direct current in accordance with the respective reception frequencies. Here, since the structure of the rectifier circuit is well known, description thereof is omitted.

  The DC power rectified by the rectifier circuits 202H and 202V is synthesized by the DC synthesis circuit 204 and output from one DC synthesis output terminal. The DC synthesis circuit 204 may have a circuit configuration in which two rectifier circuits are connected in series, or may have a circuit configuration in which the rectifier circuits are connected in parallel. The load circuit can be driven by connecting the DC composite output to the load circuit via the output unit 206 (not shown).

With the configuration of the second embodiment, two types of radio waves can be simultaneously captured in a small space, and each can be converted into DC power and combined, so that DC power greater than that in the past can be obtained.
(Embodiment 3)
FIG. 14 is a diagram for explaining the configuration of the antenna device 1000 ″ according to the third embodiment of the present invention.

  In the antenna device 1000 ″ of the third embodiment, a plurality of sets of two concentric loop antennas in the second embodiment are arranged and arrayed. The EBG reflector is increased in size, and is configured to be provided in common for a plurality of sets of loop antennas.

  Wiring from the rectifier circuits 202V and 202H to the DC synthesis circuit is omitted. The DC synthesis circuit 204 may have a circuit configuration in which two rectifier circuits are connected in series or may have a circuit configuration in which the rectifier circuits are connected in parallel. Further, it may be a combined circuit combining series and parallel.

  Since the EBG reflector has an effect of suppressing propagation of radio waves in the in-plane direction, mutual coupling with adjacent pairs of loop antennas is reduced, and there is also an effect of suppressing a reduction in efficiency.

With this configuration, two types of radio waves can be received simultaneously within the same area, so that the recovered power per unit area is greater than in the past.
(Embodiment 4)
In Embodiments 1 to 3 described above, the loop antenna is used. However, the antenna may be a dipole antenna.

  FIG. 15 is a diagram for explaining the configuration of the antenna device 1002 when a dipole antenna is used.

  FIG. 15A is a top view, and FIG. 15B is a side sectional view.

  The dipole antenna 21 is for horizontally polarized waves, and matches the direction of the dipole parallel to the long side of the rectangular patch 104. The dipole antenna 22 is for vertically polarized waves, and matches the direction of the dipole parallel to the short side of the rectangular patch 104. Here, in order not to short-circuit the wiring connecting each element of the dipole antenna 21 and the wiring connecting each element of the dipole antenna 22, for example, the wiring connecting each element of the dipole antenna 21 is a substrate (for example, The wiring that connects to the front side of the printed circuit board and connects each element of the dipole antenna 22 is configured to be wired on the back side of the substrate on which the antenna is formed.

  In antenna device 1002, the configuration of the EBG structure reflector is the same as in the first to third embodiments. By using a square loop antenna as a dipole antenna, there are the following differences.

  A method for determining the dimensions of the dipole antenna will be described below.

  The width of the dipole antenna is, for example, about 1/100 wavelength. The total length of the dipole is provisionally determined to be about ½ of the desired frequency wavelength.

  First, only the dipole antenna 21 is placed on the EBG reflector and modeled on the computer. Since it is horizontally polarized, the direction of the dipole is made parallel to the long side of the rectangular patch. The frequency characteristic of the antenna reflection coefficient at the feeding point is obtained by electromagnetic field simulation. The frequency characteristic of the antenna reflection coefficient is obtained while changing the length of the dipole. Then, the dipole length when the antenna reflection coefficient is minimized at the design frequency for the horizontally polarized wave is determined as the length of the dipole antenna.

  Next, the dipole antenna 22 is added, and the length of the dipole antenna 22 is determined so that the antenna reflection coefficient is minimized at the design frequency for vertical polarization. Since the dipole antenna 22 is vertically polarized, the direction of the dipole is made to coincide with the short side of the rectangular patch.

  For example, if circularly polarized waves are transmitted / received, the horizontal length and the vertical length of the rectangular patch are such that the reflection phase of the horizontally polarized wave is 90 ° at one frequency at which circularly polarized waves are to be generated ( −90 °), and the reflection phase of the vertically polarized wave is determined to be −90 ° (90 °). On the other hand, in the present embodiment, the reflection coefficient is designed to be minimal at a desired frequency independently for each polarization direction.

  Even with the configuration as described above, it is possible to achieve the same effects as in the first to third embodiments.

  Embodiment disclosed this time is an illustration of the structure for implementing this invention concretely, Comprising: The technical scope of this invention is not restrict | limited. The technical scope of the present invention is shown not by the description of the embodiment but by the scope of the claims, and includes modifications within the wording and equivalent meanings of the scope of the claims. Is intended.

  11,12 square loop antenna, 21,22 dipole antenna, 100 EBG structure reflector, 102 ground, 104 rectangular metal patch, 106 substrate, 200 antenna, 202 rectifier, 204 synthesizer, 206 output, 208 load, 1000, 1000 ′, 1000 ″, 1002 Antenna device.

Claims (8)

A first antenna element for horizontal polarization;
The first antenna element is arranged so as to share a central position, and a second antenna element for vertical polarization,
A reflector having an electromagnetic bandgap structure provided on the back side of the first and second antenna elements;
The reflector is
A conductive ground layer;
An antenna device comprising a plurality of rectangular conductive patches periodically arranged at a predetermined height from the ground layer. At least a part of the first antenna element is parallel to one of the short side and the long side of the rectangle,
The antenna device according to claim 1, wherein at least a part of the second antenna element is parallel to the other of the short side and the long side of the rectangle.   The horizontal dimension of each rectangular conductive patch is set corresponding to the frequency of horizontal polarization of the target electromagnetic wave, and the vertical dimension of each rectangular conductive patch is the target electromagnetic wave. The antenna device according to claim 2, wherein the antenna device is set corresponding to a frequency of vertically polarized waves.   The antenna device according to claim 1, wherein the first antenna element and the second antenna element are rectangular loop antennas arranged concentrically and having different dimensions.   The antenna device according to claim 1, wherein the first antenna element and the second antenna element are dipole antennas that are arranged to be orthogonal to a common center and have different dimensions. An electromagnetic energy recovery device,
A plurality of antenna devices, the antenna device is
A first antenna element for horizontal polarization;
The first antenna element is arranged so as to share a central position, and a second antenna element for vertical polarization,
A reflector having an electromagnetic bandgap structure provided on the back surface of the first and second antenna elements;
The reflector is
A conductive ground layer;
A plurality of rectangular conductive patches periodically arranged at a predetermined height from the ground layer;
An electromagnetic wave energy recovery device comprising: a power combiner for combining power from each of the antenna devices. The power combiner is
A first rectifier circuit provided in a feeding portion of the first antenna element;
A second rectifier circuit provided in a feeding portion of the second antenna element;
The electromagnetic wave energy recovery apparatus according to claim 6, further comprising: a direct current combining circuit that combines direct current power from the first and second rectifier circuits.   The electromagnetic wave energy recovery apparatus according to claim 7, wherein the reflection plate is provided in common to the plurality of first antenna elements and the plurality of second antenna elements.