Patent Application
20230104169
The present disclosure relates to a communication module, a communication system, and a method for controlling a communication module.
When two antennas are brought closer, an isolation therebetween cannot be ensured. To ensure the isolation between the antennas, there is a technique for separating the two antennas and inserting a structure therebetween. Such a technique is described, for example, in Patent Literature 1.
Patent Literature 1: JP 2016-105583 A
Even the antennas with the isolation therebetween is ensured as described in Patent Literature 1 may sometimes be difficult to ensure the isolation depending on the installation condition of the antennas. The installation situation of the antennas is, for example, a situation in which the environment around the antennas changes due to buildings built around the antennas. When ensuring the isolation is difficult, a reception level of a reception signal when a reception wave from other communication terminals is received by the antenna may decrease, and there is room for improvement.
The present disclosure is to provide a communication module, a communication system, and a method for controlling a communication module that can suitably acquire a reception signal.
A communication module according to one aspect includes an antenna including a first antenna element at a transmission side and a second antenna element at a reception side and having an isolation characteristic between the first antenna element and the second antenna element, a transmission circuit connected to the first antenna element, a reception circuit connected to the second antenna element, and a controller configured to control the antenna, the transmission circuit, and the reception circuit. The antenna includes a first variable phase unit configured to vary a phase of a transmission wave to be transmitted from the first antenna element, and a second variable phase unit configured to vary a phase of a reception wave to be received by the second antenna element. The controller controls at least one of the first variable phase unit or the second variable phase unit to control an isolation of the antenna.
A communication system according to one aspect includes the communication module described above, and a communication terminal configured to communicate with the communication module.
A method for controlling a communication module according to one aspect is a method for controlling the communication module described above includes, by the controller, receiving a reception wave at the second antenna element to acquire a reception signal from the reception circuit and controlling at least one of the first variable phase unit or the second variable phase unit in a manner that a signal level of the reception signal acquired is smaller than a preset setting value.
According to the present disclosure, a reception signal can be suitably acquired.
A detailed description of an embodiment according to the present disclosure will be given with reference to the drawings. In the following description, similar constituent elements may be assigned the same reference signs. Furthermore, redundant descriptions may be omitted. In addition, matters that are not closely related to the description of the embodiment according to the present disclosure may be omitted from the description and illustrations. Note that the present disclosure is not limited by the following embodiment. Further, the following embodiment includes elements that can be easily conceived by those skilled in the art, elements that are substantially the same, and elements in a so-called equivalent range.
The communication module 10 is, for example, a base station. The communication module 10 includes an antenna 15, a transmission circuit 16, a reception circuit 17, a cancel circuit 18, and a controller 20. The communication module 10 transmits a transmission wave from the antenna 15 or receives a reception wave at the antenna 15. Specifically, the communication module 10 converts, at the transmission circuit 16, a transmission signal generated by the controller 20 and transmits the converted transmission signal as a transmission wave from the antenna 15. Furthermore, the communication module 10 acquires a reception signal by receiving a reception wave at the antenna 15 converts the reception signal at the reception circuit 17, and acquire the converted reception signal at the controller 20.
As illustrated in
The antenna element 111 includes a first antenna element 111a at a transmission side and a second antenna element 111b at a reception side. The first antenna element 111a is capable of oscillating at a predetermined resonant frequency. The first antenna element 111a oscillates at a predetermined resonant frequency, causing the antenna body 110 to radiate an electromagnetic wave. The second antenna element 111b is capable of receiving an electromagnetic wave in a predetermined frequency band. The second antenna element 111b receives an electromagnetic wave, causing the antenna body 110 to acquire a reception signal. The antenna body 110 can use, as an operating frequency, at least one of resonant frequency bands of at least one of the antenna elements 111. The antenna body 110 can radiate an electromagnetic wave with the operating frequency. A wavelength of the operating frequency may be an operating wavelength that is a wavelength of the electromagnetic wave with the operating frequency of the antenna body 110.
The antenna element 111, as will be described below, exhibits an artificial magnetic conductor character with respect to an electromagnetic wave with a predetermined frequency incident on a surface of the antenna element 111 substantially parallel with an X-Y plane from the positive direction of a z axis. In the present disclosure, the “artificial magnetic conductor character” means a characteristic of a surface where a phase difference between an incident wave and a reflected wave at the operating frequency is 0 degrees. On the surface having the artificial magnetic conductor character, the phase difference between the incident wave and the reflected wave in the operating frequency band ranges from −90 degrees to +90 degrees. The operating frequency band includes the resonant frequency and the operating frequency that exhibit the artificial magnetic conductor character.
The antenna element 111 exhibits the artificial magnetic conductor character as described above, enabling the radiation efficiency of the antenna body 110 to be maintained when a ground conductor 165, which will be described later, of the circuit substrate 160 is positioned at the negative direction side of the z axis of the antenna body 110 as illustrated in
The base 120 can include either a ceramic material or a resin material as a composition. Examples of the ceramic material include an aluminum oxide-based sintered body, an aluminum nitride-based sintered body, a mullite-based sintered body, a glass ceramic sintered body, crystallized glass yielded by precipitation of a crystal component in a glass base material, and a microcrystalline sintered body such as mica or aluminum titanate. Examples of the resin material include an epoxy resin, a polyester resin, a polyimide resin, a polyamide-imide resin, a polyetherimide resin, and resin materials yielded by curing an uncured product such as a liquid crystal polymer.
The base 120 is in contact with the transmission/reception conductor 130, the ground conductor 140, and the electric wire 150. The base 120 may have any shape depending on a shape of the transmission/reception conductor 130. The base 120 may be a substantially equilateral square pillar. The base 120 includes an upper surface 121 and a lower surface 122. The upper surface 121 and the lower surface 122 can respectively be the top surface and the bottom surface of the base 120, each of which is a substantially equilateral square pillar. The upper surface 121 and the lower surface 122 can be substantially parallel to the X-Y plane. Each of the upper surface 121 and the lower surface 122 can be substantially square. One diagonal line of two diagonal lines of each of the upper surface 121 and the lower surface 122 that are substantially square is along the x direction. The other diagonal line of the two diagonal lines is along the y direction. The upper surface 121 is positioned closer to the positive direction side of the z axis than the lower surface 122.
The transmission/reception conductor 130 and the ground conductor 140 may include any of a metal material, an alloy of metal materials, a cured product of metal paste, and an electrically conductive polymer as a composition. All of the transmission/reception conductor 130 and the ground conductor 140 may include the same material. All of the transmission/reception conductor 130 and the ground conductor 140 may include different materials. Any combination of the transmission/reception conductor 130 and the ground conductor 140 may include the same material. Examples of the metal material include copper, silver, palladium, gold, platinum, aluminum, chrome, nickel, cadmium lead, selenium, manganese, tin, vanadium, lithium, cobalt, and titanium. The alloy includes a plurality of metal materials. The metal paste includes the result of kneading a powder of a metal material with an organic solvent and a binder. Examples of the binder include an epoxy resin, a polyester resin, a polyimide resin, a polyamide-imide resin, and a polyetherimide resin. Examples of the electrically conductive polymer include a polythiophene polymer, a polyacetylene polymer, a polyaniline polymer, and a polypyrrole polymer.
The transmission/reception conductor 130 functions as a transmitter and a receiver, and the transmitter functions as a resonator. As illustrated in
The transmission/reception conductor 130 can resonate in the y direction by being supplied with electrical signals having reverse phases to each other from the respective first electric wire 151 and third electric wire 153, for example. When the transmission/reception conductor 130 resonates in the y direction, from the transmission/reception conductor 130, the first connection conductors 155 can be seen as an electric wall positioned at the negative direction side of the y axis, and the third connection conductors 157 can be seen as an electric wall positioned at the positive direction side of the y axis. When the transmission/reception conductor 130 resonates in the y direction, from the transmission/reception conductor 130, the positive direction side of the x axis can be seen as a magnetic wall, and the negative direction side of the x axis can be seen as a magnetic wall. When the transmission/reception conductor 130 resonates in the y direction, the transmission/reception conductor 130 is surrounded by these two electric walls and two magnetic walls, and thus, the antenna body 110 exhibits the artificial magnetic conductor character with respect to electromagnetic waves with a predetermined frequency incident on the X-Y plane included in the antenna body 110 from the positive direction side of the z axis.
The transmission/reception conductor 130 may be configured to resonate in the x direction by electromagnetic waves with a predetermined frequency incident on the X-Y plane included in the antenna body 110 from the negative direction side of the z axis and output an electrical signal with a reverse phase from each of the second electric wire 152 and the fourth electric wire 154. When the transmission/reception conductor 130 resonates in the x direction, from the transmission/reception conductor 130, the second connection conductors 156 can be seen as an electric wall positioned at the positive direction side of the x axis, and the fourth connection conductors 158 can be seen as an electric wall positioned at the negative direction side of the x axis. When the transmission/reception conductor 130 resonates in the x direction, from the transmission/reception conductor 130, the positive direction side of the y axis can be seen as a magnetic wall, and the negative direction side of the y axis can be seen as a magnetic wall. When the transmission/reception conductor 130 resonates in the x direction, the transmission/reception conductor 130 is surrounded by these two electric walls and two magnetic walls, and thus, the antenna body 110 exhibits the artificial magnetic conductor character with respect to electromagnetic waves with a predetermined frequency incident on the X-Y plane included in the antenna body 110 from the positive direction side of the z axis.
As illustrated in
As illustrated in
The first conductor 131 to the fourth conductor 134 may have, for example, the same shape that is substantially square. Two diagonal lines of the first conductor 131 being substantially square and two diagonal lines of the third conductor 133 that is substantially square are along the x direction and the y direction. A length of the diagonal line along the y direction of the first conductor 131 and a length of the diagonal line along the y direction of the third conductor 133 may be approximately a quarter of the operating wavelength. Two diagonal lines of the second conductor 132 that is substantially square and two diagonal lines of the fourth conductor 134 that is substantially square are along the x direction and the y direction. A length of the diagonal line along the x direction of the second conductor 132 and a length of the diagonal line along the x direction of the fourth conductor 134 may be approximately a quarter of the operating wavelength.
At least a part of each of the first conductor 131 to the fourth conductor 134 may be exposed to the outside of the base 120. A part of each of the first conductor 131 to the fourth conductor 134 may be positioned inside the base 120. The entire of each of the first conductor 131 to the fourth conductor 134 may be positioned inside the base 120.
The first conductor 131 to the fourth conductor 134 expand along the upper surface 121 of the base 120. As an example, the first conductor 131 to the fourth conductor 134 may be aligned in a square lattice shape on the upper surface 121. In this case, the first conductor 131 and the fourth conductor 134; and the second conductor 132 and the third conductor 133 may be aligned along the first symmetric axis T1. The first conductor 131 and the second conductor 132; and the fourth conductor 134 and the third conductor 133 may be aligned along the second symmetric axis T2. The two diagonal directions of the square lattice aligned with the first conductor 131 to the fourth conductor 134 are along the x direction and the y direction. Of the two diagonal directions, the diagonal direction along the y direction is described as a first diagonal direction. Of the two diagonal directions, the diagonal direction along the x direction is described as a second diagonal direction. The first diagonal direction and the second diagonal direction may intersect with each other at the center O1.
The first conductor 131 to the fourth conductor 134 are positioned at predetermined intervals so as to be separated from one another. For example, as illustrated in
As illustrated in
The capacitive elements 135 are configured to capacitively connect each of the first conductor 131 to the fourth conductor 134. For example, a part of the base 120 may be positioned between the respective capacitive elements 135 and the first conductor 131 to the fourth conductor 134. A part of the base 120 is positioned between the respective capacitive elements 135 and the first conductor 131 to the fourth conductor 134, and thus, the respective capacitive elements 135 are configured to capacitively connect each of the first conductor 131 to the fourth conductor 134. An area of each of the capacitive elements 135 on the X-Y plane may be appropriately adjusted in consideration of a desired magnitude of each capacitive coupling between the respective capacitive elements 135 and the first conductor 131 to the fourth conductor 134. Distances between the first conductor 131 to the fourth conductor 134 and the respective capacitive elements 135 in the z direction may be adjusted as appropriate in consideration of a desired magnitude of capacitive coupling between the first conductor 131 to the fourth conductor 134 and the respective capacitive elements 135.
Each capacitive element 135 may be substantially parallel to the X-Y plane. The capacitive element 135 may be substantially rectangular. The four capacitive elements 135 that are substantially rectangular are a capacitive element 135 that connects between the first conductor 131 and the second conductor 132, a capacitive element 135 that connects between the second conductor 132 and the third conductor 133, a capacitive element 135 that connects between the third conductor 133 and the fourth conductor 134, and a capacitive element 135 that connects between the fourth conductor 134 and the first conductor 131. The four capacitive elements 135 are provided at the outer edge sides of the first conductor 131 to the fourth conductor 134 with respect to the center O1.
The ground conductor 140 may function as a ground of the antenna element 111. As illustrated in
As illustrated in
The electric wire 150 may be configured to supply electrical signals from the outside to the antenna element 111. The electric wire 150 may be configured to supply electrical signals from the antenna element 111 to the outside. The electric wire 150 may be a through hole conductor, a via conductor, or the like. The electric wire 150 is configured to be capable of supplying electrical signals from the antenna element 111 to the circuit substrate 160 positioned at the outside thereof or the like. The first electric wire 151 to the fourth electric wire 154 individually contact the transmission/reception conductor 130 at different positions from each other. For example, as illustrated in
The first electric wire 151 and the third electric wire 153 are configured to contribute to at least the supply of electrical signals (transmission signals) to the outside when the transmission/reception conductor 130 resonates in the y direction. The second electric wire 152 and the fourth electric wire 154 are configured to contribute to at least the supply of electrical signals (reception signals) to the reception circuit 17 when the transmission/reception conductor 130 resonates in the x direction.
The first electric wire 151 and the third electric wire 153, and the second electric wire 152 and the fourth electric wire 154 are configured to cause the transmission/reception conductor 130 to be excited in different directions. For example, the first electric wire 151 and the third electric wire 153 are configured to cause the transmission/reception conductor 130 to be excited in the y direction (a first direction). The second electric wire 152 and the fourth electric wire 154 are configured to cause the transmission/reception conductor 130 to be excited in the x direction (a second direction). With such an electric wire 150, when the transmission/reception conductor 130 is excited in one direction, the antenna body 110 can reduce the excitation of the transmission/reception conductor 130 in the other direction.
The first electric wire 151 and the third electric wire 153 are configured to cause the transmission/reception conductor 130 to be excited at a differential voltage. The second electric wire 152 and the fourth electric wire 154 are configured in a manner that the differential voltage is generated by the excitation of the transmission/reception conductor 130. The antenna body 110 can reduce the fluctuation of the center of potential in the excitation of the transmission/reception conductor 130 from the center O1 of the transmission/reception conductor 130 by causing the transmission/reception conductor 130 to be excited at the differential voltage.
As illustrated in
As illustrated in
The first electric wire 151 and the second electric wire 152 may have symmetry across the first symmetric axis T1. The third electric wire 153 and the fourth electric wire 154 may have symmetry across the first symmetric axis T1. For example, the feeding point 151A and the feeding point 152A may be line-symmetric and the feeding point 153A and the feeding point 154A may be line-symmetric, with the first symmetric axis T1 serving as an axis.
The first electric wire 151 and the fourth electric wire 154 may have symmetry across the second symmetric axis T2. The second electric wire 152 and the third electric wire 153 may have symmetry across the second symmetric axis T2. For example, the feeding point 151A and the feeding point 154A may be line-symmetric and the feeding point 152A and the feeding point 153A may be line-symmetric, with the second symmetric axis T2 serving as an axis.
A direction of connecting the first electric wire 151 and the third electric wire 153 is along the y direction. The direction of connecting the first electric wire 151 and the third electric wire 153 is along a first diagonal direction. A direction of connecting the second electric wire 152 and the fourth electric wire 154 is along the x direction. The direction of connecting the second electric wire 152 and the fourth electric wire 154 is along a second diagonal direction.
As illustrated in
The first variable phase unit 25 includes two first variable phase shifters 31 and a first inverter circuit 32. The two first variable phase shifters 31 are individually connected to the first electric wire 151 and the third electric wire 153 that constitute the first antenna element 111a. The two first variable phase shifters 31 are circuits that change the phase of the frequency of an electromagnetic wave in the first conductor 131 and the third conductor 133. The two first variable phase shifters 31 are electrically connected to the controller 20. The controller 20 controls the two first variable phase shifters 31 to change the phase of a transmission analog signal to be transmitted from the first antenna element 111a.
The first inverter circuit 32 is provided between the two first variable phase shifters 31 and electrically connects the two first variable phase shifters 31. The first inverter circuit 32 may be any of a balun, a power distribution circuit, and a delay line (delay line memory). The first inverter circuit 32 makes a resistance value from the first inverter circuit 32 to the feeding point 151A and a resistance value from the first inverter circuit 32 to the feeding point 153A substantially equal.
The second variable phase unit 26 includes two second variable phase shifters 34 and a second inverter circuit 35. The two second variable phase shifters 34 are individually connected to the second electric wire 152 and the fourth electric wire 154 that constitute the second antenna element 111b. The two second variable phase shifters 34 are circuits that change the phase of the frequency of an electromagnetic wave in the second conductor 132 and the fourth conductor 134. The two second variable phase shifters 34 are electrically connected to the controller 20. The controller 20 controls the two second variable phase shifters 34 to change the phase of a reception analog signal received by the second antenna element 111b.
The second inverter circuit 35 is provided between the two second variable phase shifters 34 and electrically connects the two second variable phase shifters 34. The second inverter circuit 35 may be, similarly to the first inverter circuit 32, any of a balun, a power distribution circuit, and a delay line (delay line memory). The second inverter circuit 35 makes resistance values from the second inverter circuit 35 to the feeding point 152A and the feeding point 154A be substantially equal to each other.
The transmission side terminal 27 is connected to the first inverter circuit 32. Furthermore, the transmission side terminal 27 is connected to the transmission circuit 16.
The reception side terminal 28 is connected to the second inverter circuit 35. Also, the reception side terminal 28 is connected to the reception circuit 17.
The antenna 15 as described above is an antenna having an isolation characteristic between the first antenna element 111a at the transmission side and the second antenna element 111b at the reception side.
The transmission circuit 16 is a digital-to-analog (D/A) converter, converts a digital transmission signal input from the controller 20 into an analog transmission signal, and outputs the converted analog transmission signal to the antenna 15.
The reception circuit 17 is an analog-to-digital (A/D) converter, converts an analog reception signal input from the antenna 15 into a digital reception signal, and outputs the converted digital reception signal to the controller 20.
The cancel circuit 18 cancels noise included in the reception signal. The cancel circuit 18 acquires a leakage signal of a transmission wave from the transmission circuit 16. The cancel circuit 18 generates a cancel signal for cancelling the noise included in the reception signal of the reception circuit 17 based on the acquired leakage signal. The cancel circuit 18 outputs the generated cancel signal to the reception circuit 17. The reception circuit 17 cancels the noise included in the reception signal based on the cancel signal.
The controller 20 comprehensively controls operations of the communication module 10 to implement various functions. The controller 20 includes integrated circuits such as a central processing unit (CPU), a field-programmable gate array (FPGA), and the like. Specifically, the controller 20 executes a program for controlling the isolation of the antenna 15 or executes a program for controlling the cancel circuit 18.
The communication module 10 described above controls the isolation of the first antenna element 111a at the transmission side by controlling the two first variable phase shifters 31 of the antenna 15 by the controller 20. In addition, the communication module 10 controls the isolation of the second antenna element 111b at the reception side by controlling the two second variable phase shifters 34 of the antenna 15 by the controller 20. Furthermore, the communication module 10 controls the noise of the reception signal by controlling the cancel circuit 18 of the antenna 15 by the controller 20, thereby ensuring the isolation between the first antenna element 111a and the second antenna element 111b.
Each of the plurality of communication terminals 12 includes an antenna 41, a wireless communication circuit 42, and a sensor 43. The antenna 41 is only required to be capable of performing transmission to and/or reception from the communication module 10, and may be, for example, a dipole antenna or the like. The antenna 41 may be a circular polarization antenna, or an antenna performing conversion to an orthogonal polarization wave. The wireless communication circuit 42 is, for example, a radio frequency integrated circuit (RFIC), and is electrically connected to the antenna 41. The wireless communication circuit 42 is input with a signal from the communication module 10 through the antenna 41, and outputs a signal through the antenna 41 toward the communication module 10. The sensor 43 is electrically connected to the wireless communication circuit 42. The sensor 43 may be any sensor, and outputs the detection result by sensing to the wireless communication circuit 42.
Next, with reference to
The communication module 10 is initialized so as to be in an initial state (step S11). The communication module 10 receives a transmission wave from the first antenna element 111a in the initial state as a reception wave and acquires a reception signal (step S12). When the reception signal is acquired, the controller 20 of the communication module 10 determines whether a signal level of the acquired reception signal is smaller than a preset threshold value or not (step S13). In step S13, for example, a minimum value is set as the threshold value. In step S13, when the controller 20 determines that the signal level is not smaller than the threshold value (step S13: NO), the controller 20 executes the isolation control of the antenna 15 (step S14).
In step S14, the controller 20 controls the isolation of the first antenna element 111a at the transmission side by controlling the two first variable phase shifters 31 of the antenna 15. In other words, the controller 20 controls the isolation of the first antenna element 111a such that the signal level of the reception signal is smaller than the threshold value. Similarly, in step S14, the controller 20 controls the isolation of the second antenna element 111b at the reception side by controlling the two second variable phase shifters 34 of the antenna 15. In other words, the controller 20 controls the isolation of the second antenna element 111b such that the signal level of the reception signal is smaller than the threshold value. Note that in step S14, the isolation of at least one of the first antenna element 111a or the second antenna element 111b can be controlled. After performing step S14, the controller 20 proceeds to step S12 again.
In step S13, when the controller 20 determines that the signal level of the reception signal is smaller than the threshold value (step S13: YES), the controller 20 terminates the isolation control because of the fact that an isolation characteristic is held between the first antenna element 111a and the second antenna element 111b.
Note that in step S14, the controller 20 controls the two first variable phase shifters 31 and the two second variable phase shifters 34 of the antenna 15 but may control the capacitive elements 135. That is, in step S14, the controller 20 may control the isolation between the first antenna element 111a and the second antenna element 111b by adjusting capacitances of the four capacitive elements 135.
Next, with reference to
The communication module 10 receives a reception wave from the communication terminal 12 and acquires a reception signal (step S21). When the reception signal is acquired, the controller 20 of the communication module 10 determines whether a signal level of the acquired reception signal is smaller than a preset threshold value or not (step S22). In step S22, for example, a minimum value is set as the threshold value. In step S22, when the controller 20 determines that the signal level is not smaller than the threshold value (step S22: NO), the control of the cancel circuit 18 is performed (step S23).
In step S23, the controller 20 adjusts a cancel signal generated by the cancel circuit 18. As illustrated in
In step S22, when the controller 20 determines that the signal level of the reception signal is smaller than the threshold value (step S22: YES), the controller 20 terminates the control of the cancel circuit 18 because of the fact that an isolation characteristic is held between the first antenna element 111a and the second antenna element 111b.
Next, attenuation characteristics of the antenna will be described with reference to
As described above, in the communication module 10 according to the embodiment and the method for controlling the communication module 10, the controller 20 can control at least one of the first variable phase unit 25 or the second variable phase unit 26 to control the isolation of the antenna 15. Thus, since the isolation of the antenna 15 can be appropriately adjusted according to the reception environment, it is possible to suitably acquire reception signals from the plurality of communication terminals 12.
Additionally, in the communication module 10 according to the embodiment, the controller 20 can control the capacitive elements 135 to control the isolation of the antenna 15. Thus, the isolation of the antenna 15 can be appropriately adjusted depending on the reception environment.
Further, in the communication module 10 according to the embodiment, the controller 20 can control the cancel circuit 18 to cancel the noise of the transmission wave included in the reception signal. Thus, the isolation of the antenna 15 can be appropriately adjusted depending on the reception environment.
Additionally, with the communication module 10 according to the embodiment, the signal level of a reception signal acquired at the antenna 15 can be made smaller than a preset setting value. Thus, the noise included in the reception signal can be suitably reduced.
Additionally, in the communication module 10 according to the embodiment, the third electric wire 153 of the antenna body 110 is positioned at the side opposite to the first electric wire 151 in they direction as viewed from the center O1 of the transmission/reception conductor 130, and the fourth electric wire 154 is positioned at the side opposite to the second electric wire 152 in the x direction as viewed from the center of the transmission/reception conductor 130. Thus, the antenna 15 having an isolation characteristic between the first antenna element 111a and the second antenna element 111b can be used.
Furthermore, in the communication system 1 according to the embodiment, communication can be suitably performed even when installation environment changes between the communication module 10 and the communication terminal 12.
Note that, in the embodiment, the cancel circuit 18 is used, but a configuration may be employed in which the cancel circuit 18 is omitted as long as the controller 20 controls at least one of the first variable phase unit 25 or the second variable phase unit 26 to sufficiently ensure the isolation characteristic.
Additionally, in the embodiment, the cancel circuit 18 is controlled after the first variable phase unit 25 and the second variable phase unit 26 of the antenna 15 are controlled, but the embodiment is not limited thereto, and the first variable phase unit 25 and the second variable phase unit 26 may be controlled after the cancel circuit is controlled.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2020-058485 | Mar 2020 | JP | national |
The present application is a National Phase of International Application Number PCT/JP2021/009923, filed Mar. 11, 2021, and claims priority based on Japanese Patent Application No. 2020-058485, filed Mar. 27, 2020.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2021/009923 | 3/11/2021 | WO |
