JP6150329B2 - Resonant frequency variable antenna, electromagnetic wave energy recovery device including the same, and method for adjusting resonant frequency variable antenna - Google Patents

Description

  The present invention relates to an array antenna for recovering electromagnetic wave energy, and in particular, a resonant frequency variable antenna capable of adjusting the resonant frequency of each antenna constituting the array antenna at once, an electromagnetic wave energy recovery apparatus including the same, and The present invention relates to a method for adjusting a resonant frequency variable antenna.

  Various methods for adjusting the resonant frequency of an antenna are known. For example, in Patent Documents 1 and 2 below, a variable capacitor (capacitor) is arranged in a loop of a loop antenna, and the resonance frequency is adjusted by changing the capacitance of the capacitor, and radio waves having a desired frequency are transmitted or transmitted. A technique for enabling reception is disclosed. As the variable capacitor, a capacitor such as a varactor diode that controls the capacitance electrically by applying a voltage is known. Also known is a trimmer capacitor or the like that controls the capacitance by mechanically moving (rotating) the electrode of the capacitor to change the opposing area of both electrodes.

  Regarding the microstrip antenna, for example, in Patent Documents 3 and 4 below, an antenna radiating element is provided on the first surface of a dielectric layer using a variable dielectric constant material whose dielectric constant changes depending on an applied electric field, and the second surface is grounded. An antenna that can adjust the resonance frequency by providing a conductor is disclosed. Since the dielectric constant of the variable dielectric constant material changes depending on the strength of the electric field applied between the antenna radiating element and the ground conductor, the electrical length of the antenna radiating element changes and the resonance frequency can be adjusted.

  Patent Document 5 below discloses an antenna having adjusting means for changing the distance between a dielectric plate having a radiating element and a dielectric plate having a ground conductor. When the distance between the two dielectric plates is changed, the capacitance between the radiating element and the ground conductor is changed, so that the resonance frequency of the antenna can be adjusted.

  As a field that requires such adjustment of the resonance frequency, there is a receiving antenna for a mobile terminal (such as a mobile phone or a smartphone) for receiving radio waves of terrestrial digital broadcasting implemented in a wide frequency band. Since the carrier frequency of terrestrial digital broadcasting varies depending on the region of Japan, it is possible to view the broadcast in that region on the mobile terminal by adjusting the resonant frequency of the antenna at the place where the mobile terminal is used.

  In recent years, research has been conducted to recover broadcast or communication radio waves existing in the environment as electric power. Also for such an electromagnetic wave energy recovery antenna, in order to efficiently receive radio waves, it is necessary to adjust the resonance frequency of the antenna according to the radio wave environment of the region where the recovery is performed.

JP-A-6-177636 JP 2009-89148 A JP 2012-85145 A Japanese Patent Laid-Open No. 5-90827 JP-A-9-162632

  In the collection of electromagnetic wave energy, broadcast or communication radio waves existing in the environment are weak as power, and sufficient power cannot be collected with only one antenna. In order to recover a large amount of power, it is necessary to arrange a plurality of antennas in an array and synthesize the minute power recovered by each antenna (coil). In that case, it is necessary to adjust the reception frequency (resonance frequency) of each antenna. When the number of antennas is large, the adjustment work is complicated, and there is a problem that adjustment takes a long time.

  In addition, among the adjustment methods of the resonance frequency, the electrical adjustment methods disclosed in Patent Documents 1 to 4 consume power for adjustment, which is contrary to the purpose of electromagnetic wave energy recovery. Become. Although it is conceivable to use the collected electric power for adjustment, there is a problem that the supply amount to a target electric circuit (hereinafter simply referred to as a circuit) is reduced. Moreover, since a variable element and a circuit for controlling the variable element are required for each antenna, there is a problem that the structure is complicated and the cost is increased. Thus, depending on the electrical adjustment method, there is a problem that efficient recovery of electromagnetic wave energy cannot be realized.

  On the other hand, the mechanical adjustment method disclosed in Patent Document 5 does not consume power during adjustment and can supply all of the recovered power to a target circuit. However, since it is necessary to manually adjust the resonance frequency for each antenna arranged in an array, if there are a large number of antennas, there is a problem that adjustment takes time and labor, and the cost is high.

  Therefore, the present invention provides a variable resonance frequency that can easily adjust each resonance frequency of a plurality of arranged antennas (hereinafter, the plurality of antennas are also referred to as array antennas) at a time without consuming power. An object of the present invention is to provide an antenna, an electromagnetic wave energy recovery device including the antenna, and a method for adjusting a resonant frequency variable antenna.

  The resonance frequency variable antenna according to the first aspect of the present invention is a resonance frequency variable antenna used for recovery of electromagnetic wave energy. This resonant frequency variable antenna is formed of a dielectric, a first plate-like body in which a plurality of antennas having the same shape are arranged on one surface, and a dielectric, and one of the first plate-like bodies is formed. A second plate disposed on the surface side, one surface of the second plate opposed to one surface of the first plate, and one surface of the first plate The holding | maintenance part which hold | maintains a 1st plate-shaped body and a 2nd plate-shaped body is provided.

  Since the resonance frequency of each coil can be set to the same frequency by keeping the distance between the first plate and the second plate constant regardless of the location of the plate, The variable frequency antenna can selectively and efficiently recover electromagnetic energy.

  Preferably, the holding unit includes a first adjustment unit that changes the interval.

  By adjusting the distance between the first plate and the second plate, the resonance frequency of each antenna can be adjusted to the frequency of the electromagnetic wave to be collected. Therefore, electromagnetic wave energy can be efficiently recovered according to the place where the resonant frequency variable antenna is installed.

  More preferably, the antenna is a loop antenna having a gap, and the second plate-like body is metal at a position corresponding to each of the plurality of gaps on one surface or the other surface of the second plate-like body. With a plate.

  By disposing a metal plate in the vicinity of the gap of the loop antenna, the resonance frequency of the loop antenna can be changed, and electromagnetic wave energy can be efficiently recovered by the resonance frequency variable antenna.

  More preferably, the first plate-like body and the second plate-like body have a flat plate shape, and the holding portion includes a second adjustment portion that is displaced along one surface of the first plate-like body.

  By displacing the second plate-like body in parallel with the first plate-like body, it is possible to change the relative position between the gap of each loop antenna and each metal plate, and thereby the resonance of each antenna. The frequency can be adjusted to the frequency of the electromagnetic wave to be collected. Therefore, electromagnetic wave energy can be efficiently recovered according to the place where the resonant frequency variable antenna is installed.

  Preferably, the first plate-like body and the second plate-like body have a flat plate shape and are arranged in close contact with each other.

  As a result, the state in which the resonance frequency of each coil is set to the same frequency can be stably maintained, and electromagnetic energy can be selectively and efficiently recovered by the resonance frequency variable antenna.

  More preferably, each of the first plate-like body and the second plate-like body is a flat plate having a constant thickness, which is uniformly formed of one kind of simple substance or mixture.

  As a result, the resonant frequency variable antenna can have a simple configuration, and electromagnetic wave energy can be stably recovered.

  More preferably, the resonant frequency variable antenna further includes a third plate-like body having a dielectric constant or thickness different from that of the second plate-like body, which is substituted for the second plate-like body.

  Accordingly, the resonance frequency can be easily adjusted, and the setting of the resonance frequency variable antenna becomes easy.

  An electromagnetic wave energy recovery device according to a second aspect of the present invention is connected to the resonance frequency variable antenna and each of the plurality of antennas on a one-to-one basis, and rectifies an AC signal generated by the interaction between the antenna and the electromagnetic wave. And a rectifying unit for outputting and a combining unit for combining and outputting the output signals of the plurality of rectifying units.

  Thereby, electromagnetic wave energy can be selectively and efficiently recovered.

  The method for adjusting a resonant frequency variable antenna according to the third aspect of the present invention is formed of a dielectric, a first plate-like body in which a plurality of antennas having the same shape are arranged on one surface, and a dielectric. And a second plate-like body disposed on one surface side of the first plate-like body, and a method for adjusting a resonant frequency variable antenna used for collecting electromagnetic energy. This adjustment method includes a step of arranging a third plate-like body having a dielectric constant or thickness different from that of the second plate-like body, instead of the second plate-like body.

  By disposing a plate having a predetermined dielectric constant with respect to the first plate, the resonance frequency can be easily adjusted, and the setting of the resonance frequency variable antenna is facilitated.

  A method for adjusting a resonant frequency variable antenna according to a fourth aspect of the present invention is formed of a dielectric, a first plate-like body in which a plurality of antennas having the same shape are arranged on one surface, and a dielectric. And a second plate-like body disposed on one surface side of the first plate-like body, and a method for adjusting a resonant frequency variable antenna used for collecting electromagnetic energy. The adjustment method includes a step of changing the distance between the one surface of the second plate-like body facing the one surface of the first plate-like body and the one surface of the first plate-like body.

  By adjusting the distance between the first plate and the second plate, the resonance frequency of each antenna can be adjusted to the frequency of the electromagnetic wave to be collected. Therefore, electromagnetic wave energy can be efficiently recovered according to the place where the resonant frequency variable antenna is installed.

  The resonant frequency variable antenna adjustment method according to the fifth aspect of the present invention is a flat plate-like first plate shape in which a plurality of loop antennas having the same shape and formed of a dielectric are disposed on one surface. And a plate-like plate disposed on one surface of the first plate-like body, formed of a dielectric, and a metal plate corresponding to each of the plurality of gaps. A method for adjusting a resonant frequency variable antenna including a second plate-like body and used for collecting electromagnetic wave energy. This adjustment method includes a step of displacing the second plate-shaped body along one surface of the first plate-shaped body.

  By displacing the second plate-like body in parallel with the first plate-like body, it is possible to change the relative position between the gap of each loop antenna and each metal plate, and thereby the resonance of each antenna. The frequency can be adjusted to the frequency of the electromagnetic wave to be collected. Therefore, electromagnetic wave energy can be efficiently recovered according to the place where the resonant frequency variable antenna is installed.

  According to the present invention, it is possible to realize a variable resonance frequency antenna that can easily adjust the resonance frequency of each antenna to a predetermined value at one time without consuming electric power.

  If this resonant frequency variable antenna is used, an electromagnetic wave energy recovery device capable of recovering electromagnetic wave energy selectively and efficiently according to the radio wave environment at the installation site can be realized. This electromagnetic wave energy recovery device takes less time and effort to adjust the resonance frequency at the installation location, and can reduce costs.

It is a block diagram which shows schematic structure of the electromagnetic wave energy recovery apparatus which concerns on embodiment of this invention. It is a perspective view which shows the resonant frequency variable antenna which concerns on the 1st Embodiment of this invention. It is sectional drawing which shows a part of resonant frequency variable antenna which concerns on the 1st Embodiment of this invention. It is a perspective view which shows the adjustment mechanism of the resonant frequency in the resonant frequency variable antenna shown in FIG. FIG. 5 is a front view illustrating a state in which a dielectric plate is attached to the array antenna panel by the adjustment mechanism illustrated in FIG. 4. FIG. 5 is a perspective view showing a resonance frequency adjusting mechanism different from FIG. 4. It is a perspective view which shows the resonant frequency variable antenna which concerns on the 2nd Embodiment of this invention. It is a front view which shows a part of array antenna panel of the resonant frequency variable antenna shown in FIG. It is sectional drawing which shows a part of resonant frequency variable antenna shown in FIG. It is a perspective view which shows the adjustment mechanism of the resonant frequency in the resonant frequency variable antenna shown in FIG. FIG. 11 is a front view illustrating a state in which a dielectric plate is attached to the array antenna panel by the adjustment mechanism illustrated in FIG. 10. It is a front view which shows the resonant frequency variable antenna different from FIG. It is a top view which shows the dipole antenna which performed the simulation. It is a graph which shows a simulation result. It is the front view and side view which show the resonant frequency variable antenna used for experiment. It is a graph which shows an experimental result. FIG. 16 is a front view showing a variable resonance frequency antenna in a state where the resonance frequency is different from that in FIG.

  In the following embodiments, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  Referring to FIG. 1, the electromagnetic wave energy recovery device according to the embodiment of the present invention includes a plurality of antennas 100, a plurality of rectifying units 102, a combining unit 104, and an output unit 106. The plurality of antennas 100 are arranged at predetermined positions to constitute an array antenna. Each rectifier 102 is connected in the vicinity of each antenna 100 and converts (rectifies) an AC voltage generated by the interaction between the antenna 100 and the electromagnetic wave into a DC voltage. A known technique may be used for the rectification, and the rectification unit can be realized by a known circuit.

  The synthesizer 104 synthesizes the DC power (DC voltage or DC current) output from the rectifier 102. The interconnection of the plurality of rectifying units 102 may be a serial 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. However, since the output of the rectifying unit 102 is direct current, it is hardly affected by the wiring pattern, and arbitrary wiring is possible.

  The output unit 106 converts the output power of the synthesis unit 104 into a voltage or current corresponding to the target load 108 and supplies the converted voltage or current to the load 108. The output unit 106 may be a circuit for supplying a voltage and a current according to the target load 108, and may be configured by a known voltage conversion circuit and current conversion circuit. The output unit 106 may include a power storage device such as a capacitor or a secondary battery.

(First Embodiment of Resonant Frequency Variable Antenna)
Hereinafter, a first embodiment of the resonant frequency variable antenna of the present invention will be described with reference to FIGS. As described above, the resonant frequency variable antenna is constituted by a plurality of antennas 100. Here, it is assumed that the antenna 100 is a known dipole antenna.

  Referring to FIGS. 2 and 3, the variable resonant frequency antenna includes an array antenna panel 120 and a dielectric plate 200. The array antenna panel 120 includes a substrate 122 formed of a resin having a uniform material (that is, a dielectric constant is spatially uniform), and a plurality of the same shape arranged in an array on one surface of the substrate 122. The dipole antenna 124 is provided. The lead part 126 is disposed at a feeding point (power receiving point) of the dipole antenna 124. Each rectifier 102 (not shown in FIG. 2) is connected to each lead portion 126.

  The dielectric plate 200 is made of a uniform resin. The dielectric plate 200 is disposed on the side of the surface of the substrate 122 where the dipole antenna 124 is disposed, in parallel with the substrate 122, with a predetermined distance d from the substrate 122 (including the case where d = 0). Has been.

  For convenience, FIGS. 2 and 3 show an X axis, a Y axis, and a Z axis that are orthogonal to each other (hereinafter, these three axes are also referred to as orthogonal axes). The Z axis is perpendicular to the surface of the substrate 122, and the direction from the dielectric plate 200 toward the substrate 122 is the positive direction of the Z axis. The X axis and the Y axis are set orthogonal to the Z axis and parallel to the surface of the substrate 122.

  For the substrate 122, for example, a known printed wiring board plate (a glass epoxy plate, a glass composite plate, a paper epoxy plate, a paper phenol plate, or the like) can be used. In that case, the dipole antenna 124 can be formed on the substrate 122 as a metal foil such as copper by etching or the like.

  When the dielectric plate 200 is not disposed near the dipole antenna 124, the resonance frequency of the dipole antenna 124 is mainly determined by the dielectric constant and thickness of the substrate 122 and the length of the dipole antenna 124. When the dielectric plate 200 is brought closer to the array antenna panel 120 (may be brought into close contact), the wavelength shortening effect of the dipole antenna 124 changes due to the influence of the dielectric constant of the dielectric plate 200, so that the electrical length of the dipole antenna 124 is increased. become longer. For this reason, the resonant frequency of the dipole antenna 124 can be lowered. Since the wavelength shortening effect varies depending on the dielectric constant of the dielectric plate 200, a plurality of dielectric plates having different dielectric constants are prepared, and an appropriate dielectric plate can be selected to adjust to a desired resonance frequency. it can. The resonance frequency of the dipole antenna 124 can be further reduced as the dielectric constant of the dielectric plate increases.

  With reference to FIGS. 4 and 5, a mechanism for mounting a dielectric plate on the array antenna panel 120 and a method for adjusting the resonance frequency of the resonance frequency variable antenna will be described. In FIG. 4, the same orthogonal axes as shown in FIGS. 2 and 3 are displayed. The mechanism for attaching the dielectric plate to the array antenna panel 120 includes the same number (four in FIG. 4) of the support column 400, the spacer 402, and the fixing unit 404.

  One end of the support column 400 is fixed to the surface of the array antenna panel 120 so that the central axis of the support column 400 is perpendicular to the surface of the array antenna panel 120. The support column 400 has a spiral groove (not shown) having a predetermined pitch on the outer peripheral surface, and functions as a bolt. As a method of fixing the column part 400 to the surface of the array antenna panel 120, an adhesive, screw fixing from the back surface of the array antenna panel 120, or the like can be used. The spacer 402 is a column (having a plate-like body whose length is smaller than the outer diameter) having a predetermined length and having a hole through which the support column 400 can pass. The fixing portion 404 has a spiral groove formed on the inner wall of the hole corresponding to the spiral groove formed in the support column 400, and functions as a nut for the support column 400 functioning as a bolt.

  The column part 400, the spacer 402, and the fixing part 404 are sized so as not to change the resonance frequency of the dipole antenna 124, and are separated from the dipole antenna 124 so as not to change the resonance frequency of the dipole antenna 124. As long as it is made, it may be made of metal or resin.

  With the mechanism configured as described above, the dielectric plate 220 in which the hole 222 through which the support column 400 can penetrate can be fixed to the array antenna panel 120. First, the spacer 402 having the same length is attached to each of the support columns 400. Next, the dielectric plate 220 is mounted so that the support column 400 passes through the hole 222 of the dielectric plate 220. Finally, the fixing portion 404 is attached to the support column 400 and fixed with screws. As a result, as shown in FIG. 5, the dielectric plate 220 is fixed to the array antenna panel 120 at a predetermined distance corresponding to the length of the spacer.

  Thus, the resonance frequencies of the plurality of dipole antennas 124 on the array antenna panel 120 can be set to a predetermined value at once. Since the distance between the dielectric plate 220 and the array antenna panel 120 can be changed by using different height spacers, the resonance frequency of the dipole antenna 124 can be changed (the simulation result described later). See). Therefore, the work amount and time required for adjusting the resonance frequency of the plurality of dipole antennas 124 on the array antenna panel 120 can be significantly reduced as compared with the case of adjusting each antenna.

  Even if there is only one type of dielectric plate 220, if a plurality of types of spacers having different heights are prepared in advance, the resonance of the dipole antenna 124 can be recovered to the frequency of the recoverable radio wave according to the radio wave environment at the installation location. It is possible to adjust the frequency. By using a spacer having a lower height, the resonance frequency of the dipole antenna 124 can be lowered. If no spacer is used, the dielectric plate 220 can be fixed in close contact with the array antenna panel 120, and the resonance frequency of the dipole antenna 124 can be minimized. Therefore, if the dipole antenna 124 of the array antenna panel 120 is designed to have a relatively high resonance frequency in the absence of the dielectric plate 200 in the vicinity, the dipole antenna 124 can be used according to the radio wave environment at the installation location. Can be adjusted to be low, and electromagnetic energy recovery at the installation location can be performed efficiently.

  A plurality of types of dielectric plates having different dielectric constants may be prepared in advance, and the resonant frequency of the dipole antenna 124 may be adjusted by appropriately changing the dielectric plate attached to the array antenna panel 120.

  Alternatively, a plurality of dielectric plates having different thicknesses may be prepared in advance, and the resonance frequency of the dipole antenna 124 may be adjusted by appropriately changing the dielectric plate attached to the array antenna panel 120. If the thickness is increased, the resonance frequency can be further lowered.

  Alternatively, the resonance frequency of the dipole antenna 124 may be adjusted by attaching a plurality of dielectric plates to the array antenna panel 120.

  In addition, a plurality of types of dielectric plates having different dielectric constants and a plurality of dielectric plates having different thicknesses are prepared in advance, and one or more dielectric plates to be mounted on the array antenna panel 120 are appropriately changed. By doing so, the resonance frequency of the dipole antenna 124 may be adjusted.

  As described above, a plurality of types of spacers having different heights, a plurality of types of dielectric plates having different dielectric constants, and a plurality of dielectric plates having different thicknesses are prepared, and one or more dielectric plates are appropriately prepared. And the spacer are selected, the resonance frequency of the dipole antenna 124 can be accurately adjusted to a target value.

  The mechanism for arranging the array antenna panel 120 and the dielectric plate at a predetermined interval is not limited to the mechanism shown in FIG. 4, and any mechanism can be used. For example, a mechanism as shown in FIG. 6 may be used. The support part 420 includes a base part 422, a first side part 424, and a second side part 246. A plurality of slits 428 and 430 having a predetermined width are formed on the opposing surfaces of the first side portion 424 and the second side portion 426, respectively. The adjacent spacings d1 and d2 of the corresponding slits are equal.

  As shown in FIG. 6, the array antenna panel 120 and the dielectric plate 200 can be attached to the slit of the support portion 420. The widths of the slits 428 and 430 are preferably substantially equal to the thicknesses of the array antenna panel 120 and the dielectric plate 200 so that the array antenna panel 120 or the dielectric plate 200 can be held with little play. Since the support part 420 is configured as described above, the mounted array antenna panel 120 and the dielectric plate 200 can be held in parallel at a predetermined interval. Since the distance between the array antenna panel 120 and the dielectric plate 200 can be adjusted by appropriately changing the slits for mounting the array antenna panel 120 and the dielectric plate 200, the dipole antennas 124 on the array antenna panel 120 can be adjusted. Can be adjusted at once.

  As described above, the adjacent distances d1 and d2 of the corresponding slits are preferably d1 = d2, but the adjacent distance d1 of the slits formed in the first side part 424 (that is, formed in the second side part 426). The adjacent interval d2) between the slits may not be constant. For example, when the thicknesses of the array antenna panel 120 and the dielectric plate 200 are the same, by appropriately selecting a slit for mounting the array antenna panel 120 and the dielectric plate 200 from the plurality of slits 428, the array antenna can be obtained. A plurality of adjacent intervals d1 can be designed such that the interval between the panel 120 and the dielectric plate 200 increases substantially continuously from a value obtained by subtracting the plate thickness t of the array antenna panel 120 from the minimum value of d1. .

  The base part 422, the first side part 424, and the second side part 426 constituting the support part 420 may be made of metal or resin as long as the resonance frequency of the dipole antenna 124 is not changed. .

(Second Embodiment of Resonant Frequency Variable Antenna)
Hereinafter, a variable resonance frequency antenna according to a second embodiment of the present invention will be described with reference to FIGS. Here, it is assumed that the plurality of antennas 100 constituting the resonant frequency variable antenna of the present embodiment are loop antennas.

  Referring to FIGS. 7 to 9, the variable resonant frequency antenna includes an array antenna panel 140 and a plate-shaped dielectric plate 240. The array antenna panel 140 includes a substrate 142 made of a uniform resin material and a plurality of loop antennas 144 having the same shape and arranged in an array on one surface of the substrate 142. As shown in FIG. 8, the lead portion 146 is disposed at the feeding point (power receiving point) of the loop antenna 144. Each lead part 146 is connected to each rectifying part 102 (not shown in FIGS. 7 and 8). In the loop antenna 144, a gap portion 148 is formed at a position facing the feeding point across the center 0.

  The dielectric plate 240 is formed of a uniform resin, and is disposed in close contact with the surface of the substrate 142 on which the loop antenna 144 is disposed. In FIG. 7, for convenience, the substrate 142 and the dielectric plate 240 are shown separated from each other. A rectangular metal plate 242 is arranged on each surface of the dielectric plate 240 that is not in close contact with the substrate 142 so as to correspond to each gap portion 148. That is, the relative positional relationship between the plurality of gap portions 148 on the substrate 142 is the same as the relative positional relationship between the plurality of metal plates 242 on the dielectric plate 240.

  7 to 9 are set in the same manner as in FIG. 2 with respect to the substrate 142, and FIG. 9 is a cross-sectional view of the gap portion 148.

  For the substrate 142, for example, a known printed wiring board plate can be used. In that case, the loop antenna 144 can be formed on the substrate 142 as a metal foil such as copper by etching or the like. Similarly, the metal plate 242 can be formed on the dielectric plate 240 as a metal foil such as copper. A printed wiring board may also be used as the dielectric plate 240. Usually, a printed circuit board for forming a circuit has a relatively low relative dielectric constant, and therefore a plate of resin or the like having a higher dielectric constant is used. It is preferable to use it.

  When the dielectric plate 240 is not disposed near the loop antenna 144, the resonance frequency of the loop antenna 144 mainly includes the dielectric constant and thickness of the substrate 142, the length (circumferential length) of the loop antenna 144, and the gap. It is determined by the capacitor capacity of the part 148. When the dielectric plate 240 is brought into close contact with the array antenna panel 140, the capacitance of the capacitor formed in the gap portion 148 of the loop antenna 144 changes due to the dielectric constant of the dielectric plate 240, and the loop antenna 144 is reduced due to the wavelength shortening effect. The electrical length of the can be changed, and the resonance frequency can be changed. That is, the resonance frequency of the loop antenna 144 can be lowered.

  Furthermore, the resonant frequency of the loop antenna 144 can also be lowered by disposing the metal plate 242 in the vicinity of the gap portion 148 of the loop antenna 144. With the dielectric plate 240 in close contact with the array antenna panel 140, the resonance frequency of the loop antenna 144 decreases as the position of the dielectric plate 240 is shifted to bring the metal plate 242 closer to the gap portion 148 of the loop antenna 144 ( (See experimental results below).

  With reference to FIG. 10, a mechanism for attaching a dielectric plate to array antenna panel 140 and a method for adjusting the resonance frequency of the resonance frequency variable antenna will be described. In FIG. 10, the same orthogonal axes as shown in FIGS. 7 to 9 are displayed. The mechanism for attaching the dielectric plate to the array antenna panel 140 includes the same number (four in FIG. 10) of the supporting column portions 400 and the fixing portions 404 as in FIG. Here, since the array antenna panel 140 and the dielectric plate are brought into close contact with each other, the spacer 402 shown in FIG. 4 is not used.

  The method of fixing the column 400 to the surface of the array antenna panel 140, the function of the column 400 and the fixing unit 404, the method of attaching the dielectric plate 260 to the array antenna panel 140 by the column 400 and the fixing unit 404, etc. This is the same as in the first embodiment. However, although the circular hole 222 was formed in the dielectric plate 220 in FIG. 4, the first feature is that the dielectric plate 260 has a long hole 262 through which the support column 400 can pass. Different from the embodiment.

  A state in which the dielectric plate 260 is attached to the array antenna panel 140 is shown in FIG. The long hole 262 can change the relative position between the array antenna panel 140 and the dielectric plate 260 in the Y-axis direction. Therefore, the relative position in the Y-axis direction between the gap portion 148 and the metal plate 242 can be changed, and the resonance frequency of the loop antenna 144 can be adjusted as described above. FIG. 11 shows a state in which the metal plate 242 is shifted slightly upward (in the negative direction of the Y axis) with respect to the gap portion 148. By disposing the metal plate 242 at an appropriate position with respect to the gap portion 148 and tightening the fixing portion 404, the dielectric plate 260 can be fixed to the array antenna panel 140, and the resonance frequency can be fixed to a specific value. .

  Although the case where the array antenna panel 140 and the dielectric plate 260 are brought into close contact with each other has been described above, the present invention is not limited to this. As described with respect to the first embodiment, the array antenna panel 140 and the dielectric plate 260 may be arranged with a predetermined interval using the spacer 402. For example, a plurality of types of spacers having different heights are prepared in advance, the distance between the array antenna panel 140 and the dielectric plate 260 is adjusted, and the in-plane direction between the metal plate 242 and the gap portion 148 (Y-axis) By adjusting the relative position of the (direction), it is possible to adjust the resonance frequency of each loop antenna 144 so as to match the target value more accurately.

  In addition, the method for adjusting the resonance frequency of the dipole antenna 124 described with respect to the first embodiment can be similarly used for the loop antenna 144. For example, a plurality of types of dielectric plates having different dielectric constants and a plurality of dielectric plates having different thicknesses are prepared, and the resonance frequency of the loop antenna 144 is adjusted using one or a plurality of dielectric plates. May be. In this case, the number of dielectric plates provided with a metal plate may be one, and the other dielectric plates need not be provided with metal plates.

  Although the case where one metal plate 242 is used for adjusting the resonance frequency of one loop antenna 144 has been described above, the present invention is not limited to this. For example, as shown in FIG. 12, a plurality of metal plates may be used for adjusting the resonance frequency of one loop antenna 144. In FIG. 12, three metal plates 284, 286, and 288 having different lengths are arranged in the metal plate arrangement region 282 on the dielectric plate 280 corresponding to the gap portion of the loop antenna 144. Also in this case, the resonance frequency of the loop antenna can be changed by moving the dielectric plate 280 in the Y-axis direction. By arranging a plurality of metal plates having different lengths, the resonance frequency of the loop antenna can be changed by changing the length of the metal plate positioned in the vicinity of the gap portion. Therefore, since the parameter for adjusting the resonance frequency increases, the resonance frequency can be adjusted to the target frequency with higher accuracy.

  Although the case where the surface of the dielectric plate 240 where the metal plate 242 is not disposed and the surface of the array antenna panel 140 where the loop antenna 144 is disposed is described above, the present invention is not limited to this. The resonant frequency variable antenna may be formed by disposing the surface of the dielectric plate 240 on which the metal plate 242 is disposed and the surface of the array antenna panel 140 on which the loop antenna 144 is disposed. Even in such a case, similarly to the above, the relative position of the array antenna panel 140 and the dielectric plate 240 is changed along the surface, the interval between the array antenna panel 140 and the dielectric plate 240 is changed, and the like. The resonance frequency of the antenna 144 can be changed.

  Although the case where a circular loop antenna is arranged on the array antenna panel has been described above, the present invention is not limited to this. The electric conductor that forms the antenna may have a gap at a predetermined position (position where a standing wave can be formed) other than the feeding portion, and the entire shape of the electric conductor may be an annular shape. Good. For example, a loop antenna having a rectangular shape or a shape close to a rectangular shape may be used. In addition to a loop antenna having a single turn, a loop antenna having a plurality of turns, such as an antenna used for an RFID chip, may be used.

  In the above description, a case where a plurality of antennas (dipole antennas or loop antennas) are arranged in a lattice shape so as to face the same direction is described, but the present invention is not limited to this. The antenna orientation and the mutual arrangement of the antennas are not affected by the resonance frequency of each antenna, and the rectifier 102 can be connected to the lead portion, and a DC voltage (DC current) is transmitted from the rectifier 102 to the synthesizer 104. Any arrangement can be used as long as the wiring to be arranged can be appropriately arranged. For example, in FIG. 2 or FIG. 7, the positions of the antennas in the even-numbered columns (Y-axis direction) are shifted from the antennas in the odd-numbered columns by ½ of the interval between adjacent antennas in the column direction. May be. Also, in FIG. 2 or FIG. 7, the positions of the antennas in the even-numbered rows (X-axis direction) are shifted from the antennas in the odd-numbered rows by a half of the spacing between the adjacent antennas in the row direction. May be. In FIG. 2, some of the antennas may be arranged so as to be inverted in the column direction. Further, in FIG. 7, some antennas may be arranged by being inverted in the row direction.

  Although the case where the antenna which comprises an array antenna panel is a dipole antenna or a loop antenna was demonstrated above, it is not limited to this. That is, the array antenna panel only needs to be composed of antennas having the same resonance frequency and the same shape.

  In the above description, the case where the dielectric plate is a uniform flat plate in which no hole or the like is formed has been described. However, the present invention is not limited to this. In order to reduce the weight, a dielectric plate in which a hole is not formed so as not to overlap with the antenna, or a dielectric plate in which the thickness of a portion not overlapping with the antenna is thinned may be used. The same applies to the substrate. In general, the magnitude of the wavelength shortening effect depends on the dielectric existing in the vicinity of the electric field in the vicinity of the metal forming the antenna. For this reason, even if a hole is made in a part of the dielectric plate that is a part away from the metal forming the antenna (preferably a part far enough away), the wavelength shortening effect is not significantly affected, and the resonance frequency The adjustment function can be kept. This makes it possible to reduce the weight of the dielectric plate and save material.

  Although the case where the dielectric plate and the substrate are flat plates has been described above, the present invention is not limited to this. The shape is sufficient as long as the dielectric plate and the substrate can be brought into close contact with each other. For example, the surface in contact with the dielectric plate and the substrate is a single curvature surface or a surface composed of a plurality of curvature surfaces. May be. Even in such a shape, the resonance frequency of each antenna can be set to the same value by adjusting the distance between the dielectric plate and the substrate.

  In the above description, the case where the dielectric plate is uniformly formed of one kind of single substance or mixture has been described, but the present invention is not limited to this. The dielectric plate may be a structure in which a liquid or sol-like substance is housed in a plate-like container. The dielectric plate may be a structure in which a gel material is sandwiched between two films or the like.

  In addition, the installation location and installation method of a resonant frequency variable antenna are arbitrary, and a resonant frequency variable antenna can be installed independently. For example, you may install in the wall surface (outside wall surface, roof, indoor wall surface, or ceiling etc.) of a building. The resonant frequency variable antenna may be embedded in the wall surface. The resonant frequency variable antenna may be formed integrally with a panel for forming the wall surface.

  Below, simulation results and experimental results are shown to show the effectiveness of the present invention.

  A numerical simulation was performed on the resonant frequency of the dipole antenna. As shown in FIG. 13, a dipole antenna composed of two metal plates 180 and 182 is disposed on the surface of the substrate, and a dielectric plate is disposed in parallel to the substrate (the dipole antenna is disposed on the dielectric plate). The reflectance (dB) at the power feeding part (the part where the metal plates 180 and 182 are close to each other) was calculated by changing the frequency of the input signal within a predetermined range. . The reflectance | S11 | is a value obtained by dividing the reflected signal intensity by the incident signal intensity. As | S11 | is smaller, the signal incident on the power feeding section passes without being reflected. This is the same when the antenna is used for reception.

  In the dipole antenna, the metal plates 180 and 182 have a width w of 10 mm, a gap g of 10 mm, and an overall length L of 230.7 mm. The substrate was a square flat plate having a relative dielectric constant of 3.5, a side length of 300 mm, and a thickness of 0.75 mm. The dielectric plate was assumed to be a square flat plate having a relative dielectric constant of 9.8, a side length of 300 mm, and a thickness of 0.75 mm.

  In the case of a single substrate (without a dielectric plate), and when the interval between the substrate and the dielectric plate (distance between two opposing surfaces) is changed in the range of 0 to 10 mm at intervals of 2 mm, 0. The reflectance | S11 | was calculated in the frequency range of 3 to 0.7 GHz. The result is shown in FIG. In any case, the reflectance | S11 | changes so as to take a minimum value at a certain frequency. The frequency at which the reflectance | S11 | becomes the minimum value is the resonance frequency.

  Table 1 shows the resonance frequencies obtained from the graph in correspondence with the distance between the substrate and the dielectric plate.

表１から分かるように、ダイポールアンテナの共振周波数は、近くに誘電体板がない状態が最も高く、誘電体板を基板（ダイポールアンテナ）に近づけるにしたがって単調に低下し、誘電体板と基板とが密着した状態において最も低くなることが分かる。

As can be seen from Table 1, the resonance frequency of the dipole antenna is highest when there is no dielectric plate nearby, and decreases monotonously as the dielectric plate approaches the substrate (dipole antenna). As can be seen from FIG.

  Therefore, if the resonance frequency corresponding to the distance between the substrate and the dielectric plate is obtained in advance by simulation or experiment using the dipole antenna, the substrate, and the dielectric plate constituting the array antenna, the array antenna can be used. The resonance frequency can be easily set to a desired value at the installation location.

  In addition, since the surrounding environment of an array antenna changes with the installation location of an array antenna, such an adjustment method may not be enough. In that case, radio wave energy can be recovered most efficiently if the distance between the substrate and the dielectric plate is finely adjusted after coarse adjustment to the target resonance frequency and further monitoring the received signal strength of the antenna. Thus, the array antenna can be adjusted.

  Experiments were conducted on the resonant frequency of the loop antenna. As shown in FIG. 15, a substrate 160 having a copper foil loop antenna 162 disposed on the surface thereof and a dielectric plate 300 having a copper foil piece 302 disposed on the surface thereof are brought into close contact, and terminals 170 connected to the loop antenna 162 and The signal reflectivity was measured via 172.

  The loop antenna has a width w of 10 mm, a radius r of a circle passing through the center of the width of 97 mm, and a gap length g of 5 mm. The copper foil piece 302 has a length of 20 mm and a width of 10 mm. Each of the substrate 160 and the dielectric plate 300 has a relative dielectric constant of 3.5 and a thickness of 0.75 mm.

  In the case of the substrate 160 having the loop antenna 162 alone (without the dielectric plate 300) and when the relative position between the substrate 160 and the dielectric plate 300 is changed, a high frequency signal is input via the terminals 170 and 172. The reflectance was obtained by measuring the reflected signal. The frequency of the input signal was changed in the range of 0.3 to 0.9 GHz.

  The reflectance | S11 | of the measurement results is shown in FIG. The broken line graph is the actual measurement result. The solid line graph is a simulation result obtained by numerical calculation under the same conditions as the experimental conditions.

  The broken line graph at the right end of FIG. 16 is a result obtained in the case of the substrate 160 alone (without the dielectric plate 300) on which the loop antenna 162 is arranged. The broken line graph at the left end is a result obtained in a state where the copper foil piece 302 is positioned closest to the gap portion of the loop antenna 162 as shown in FIG. The broken line graph in the center is a result obtained in a state where the lower end of the copper foil piece 302 is positioned at the upper end of the gap portion as shown in FIG.

  FIG. 16 shows that in any case, the reflectance | S11 | changes so as to take a minimum value at a certain frequency. The resonance frequency, which is the frequency at which the reflectance | S11 | becomes the minimum value, is highest when there is no dielectric plate nearby, and decreases when the dielectric plate is brought into close contact with the substrate (loop antenna). It can be seen that when the copper foil piece 302 is brought closer to the gap portion in this state, it is further lowered. That is, when the copper foil piece 302 is moved from the state of FIG. 17 so that the area of the portion where the gap portion and the copper foil piece overlap is increased, the resonance frequency of the loop antenna 162 decreases monotonously. Minimal in state.

  As shown in FIG. 16, the resonance frequency obtained by the experimental result can be substantially reproduced by simulation.

  As described above, even when an array antenna is configured by a loop antenna, the loop antenna, the substrate, the dielectric plate, and the metal plate are used, and in accordance with the relative position between the metal plate and the gap portion through experiments or simulations in advance. If the resonance frequency is acquired, the resonance frequency can be easily set to a desired value at the place where the array antenna is installed.

  The embodiment disclosed herein is merely an example, and the present invention is not limited to the above-described embodiment. The scope of the present invention is indicated by each claim of the claims after taking into account the description of the detailed description of the invention, and all modifications within the meaning and scope equivalent to the wording described therein are included. Including.

100 antenna 102 rectifier 104 synthesizer 106 output 108 load 120, 140 array antenna panel 122, 142, 160 substrate 124 dipole antenna 126, 146 lead 144, 162 loop antenna 148 gap 170, 172 terminals 180, 182 metal plate 200, 220, 240, 260, 280, 300 Dielectric plate 222 Holes 242, 284, 286, 288 Metal plate 262 Long hole 282 Metal plate placement area 302 Copper foil piece 400 Supporting part 402 Spacer 404 Fixing part 420 Supporting part 422 Base 424 First side portion 426 Second side portion 428, 430 Slit

Claims (7)

A resonant frequency variable antenna used for collecting electromagnetic energy,
A first plate-like body formed of a dielectric and having a plurality of antennas having the same shape arranged on one surface;
A second plate formed of a dielectric and disposed on the one surface side of the first plate;
The one surface of the second plate-like body facing the one surface of the first plate-like body and the distance between the one surface of the first plate-like body are constant. Holding means for holding the first plate-like body and the second plate-like body ,
The antenna is a loop antenna having a gap;
The second plate has a metal plate at a position corresponding to each of the plurality of gaps on the one surface or the other surface of the second plate.
The first plate and the second plate are flat.
The holding means comprises a variable resonance frequency antenna comprising first adjusting means for displacing the second plate-like body along the one surface of the first plate-like body . Said holding means further comprises a second adjusting device for changing the spacing, the resonance frequency variable antenna according to claim 1. Said first plate body and said second plate-like member is a flat plate shape, is disposed in close contact with each other, the resonance frequency variable antenna according to claim 1 or 2. Each of said first plate body and said second plate-like body, one alone or a mixture by which is uniformly formed, a flat plate thickness is constant, any one of claims 1 to 3 1 The resonance frequency variable antenna according to item. Wherein is replaced by the second plate-like member, the dielectric constant or thickness further comprises a third plate member which is different from the second plate-like member, according to any one of claims 1 4 Resonant frequency variable antenna. A resonant frequency variable antenna according to any one of claims 1 to 5 ,
Rectifying means connected to each of the plurality of antennas in a one-to-one relationship and rectifying and outputting an AC signal generated by the interaction between the antenna and an electromagnetic wave;
An electromagnetic wave energy recovery device comprising: a combining unit that combines and outputs output signals of the plurality of rectifying units. A flat plate-like first plate body formed of a dielectric material and having a gap and having a plurality of loop antennas having the same shape arranged on one surface, and on the one surface side of the first plate material A plate-like second plate-like member that is disposed, formed of a dielectric material, and arranged on one of the surfaces of a metal plate corresponding to each of the plurality of gaps, for collecting electromagnetic energy A method for adjusting a resonant frequency variable antenna used,
A method for adjusting a resonant frequency variable antenna, comprising: displacing the second plate-like body along the one surface of the first plate-like body.

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