Rectenna device and electronic apparatus

Abstract

Provided is a rectenna device capable of achieving high rectification efficiency in a wide range of intensity of input power.　This rectenna device includes: two or more antenna elements; a first rectification circuit provided for each antenna element, each first rectification circuit rectifying the output of the corresponding antenna element; and a second rectification circuit capable of synthesizing and inputting the outputs of the two or more antenna elements, the second rectification circuit rectifying the synthesized output. Control is performed in which the number of antenna elements respectively connected to the first rectification circuits and the second rectification circuit is changed.

Description

Rectenna device and electronic equipment

[0001] The present technology relates to a rectenna device and an electronic device.

[0002] As a technological trend in wireless power transfer, for example, in Japan, three radio wave bands, 920 MHz, 2.4 GHz, and 5.7 GHz, are used for microwave wireless power transmission, and wireless power transmission systems using these three radio wave bands were legislated in May 2022. In the future, the realization of wireless power transmission systems that use higher radio wave bands (e.g., millimeter wave bands around 24 GHz and higher frequency bands around 60 GHz) rather than microwaves is also being explored. These radio wave bands are also being considered for use in fifth-generation mobile communication systems (so-called 5G), Beyond 5G and 6G, which are developments of 5G, and the use of these communication systems in combination with wireless power transmission is also considered. Power supply systems using wireless power transmission are expected to be used not only for powering IoT (Internet of Things) devices, but also for powering mobile devices and wirelessly implementing USB (Universal Serial Bus). A "rectenna" is known as one of the technical elements that realizes wireless power transmission (see, for example, Patent Document 1). Rectenna is an abbreviation for Rectifying Antenna.

[0003] JP 2012-139051 A

[0004] Generally, the rectification efficiency of a rectenna depends on the characteristics of the semiconductor, and there is a problem that the efficiency drops rapidly above a certain input power intensity. For this reason, a rectenna that can achieve high rectification efficiency over a wide range of input power intensities is desired.

[0005] An object of the present technology is to provide a rectenna device that can achieve high rectification efficiency over a wide range of input power intensity, and an electronic device that includes the rectenna device.

[0006] The present technology relates to a rectenna device having, for example, two or more antenna elements, a first rectifier circuit provided for each antenna element and rectifying the output of the antenna element, and a second rectifier circuit that allows the outputs of the two or more antenna elements to be combined and input and rectifies the combined output, wherein control is performed to change the number of antenna elements connected to each of the first rectifier circuit and the second rectifier circuit. The present technology may also be an electronic device having the above-mentioned rectenna device.

[0007] 10A and 10B are diagrams to be referred to when describing the physical background related to the present technology. 10A and 10B are diagrams to be referred to when describing the physical background related to the present technology. 10B are diagrams to be referred to when describing the physical background related to the present technology. 10B are diagrams to be referred to when describing an example of the configuration of a rectenna device according to a first embodiment. 10C are diagrams to be referred to when describing an example of the operation of the rectenna device according to the first embodiment. 10D are diagrams to be referred to when describing an example of the operation of the rectenna device according to the first embodiment. 10E are diagrams to be referred to when describing an example of an effect obtained by the rectenna device according to the first embodiment. 10F are diagrams to be referred to when describing an example of the configuration of a rectenna device according to a second embodiment. 10G are diagrams to be referred to when describing an example of the configuration of a rectenna device according to a third embodiment. 10H are diagrams to be referred to when describing an example of the configuration of a rectenna device according to a fourth embodiment. 10H are diagrams to be referred to when describing an example of the configuration of a rectenna device according to a fifth embodiment. 10H are diagrams to be referred to when describing a modification of the rectenna device according to the fifth embodiment. 10H are diagrams to be referred to when describing an example of the configuration of a rectenna device according to a sixth embodiment. 10H are diagrams to be referred to when describing an example of a rectenna device according to a seventh embodiment. 10H are diagrams to be referred to when describing another example of the rectenna device according to the seventh embodiment. 10H are diagrams to be referred to when describing an example of the configuration of a rectenna device according to an eighth embodiment. 13A and 13B are diagrams for explaining a configuration example of a rectenna device according to a ninth embodiment. 13A and 13B are diagrams for explaining another configuration example of the rectenna device according to the ninth embodiment. 13A to 13J are diagrams for explaining a specific example of an electronic device to which the rectenna device according to the present technology can be applied. 13B are diagrams for explaining an example of the operation of a rectenna device according to the present technology when applied to a smartphone. 13C are diagrams for explaining an example of the operation of a rectenna device according to the present technology when applied to a smartphone. 13D are block diagrams for explaining an example of the configuration of an electronic device to which the rectenna device according to the present technology is applied. 13D are block diagrams for explaining an example of the configuration of a power transmitter constituting an example of a power transmitting and receiving system according to the present technology, and an electronic device to which the rectenna device is applied. 13E are block diagrams for explaining an example of the configuration of a power transmitter constituting another example of a power transmitting and receiving system according to the present technology, and an electronic device to which the rectenna device is applied.Fig. 10 is a flowchart for explaining an example of processing performed between a power transmitter and an electronic device in a power transmitting and receiving system according to the present technology. Fig. 11 is a diagram for explaining a modified example. Fig. 12 is a diagram for explaining a modified example. Fig. 13 is a diagram for explaining a modified example. Fig. 14 is a diagram for explaining a modified example.

[0008] Hereinafter, embodiments of the present technology will be described with reference to the drawings. Note that the embodiments described below are preferred specific examples of the present technology, and the content of the present technology is not limited to these embodiments. Note that the size and positional relationship of components shown in each drawing may be exaggerated for clarity of explanation, and in addition, to prevent the illustrations from becoming complicated, only some of the reference symbols may be shown or some of the illustrations may be simplified. Furthermore, in the following description, the same names and symbols indicate the same or similar components, and duplicate explanations may be omitted as appropriate.

[0009] The description will be given in the following order: [Physical Background] [First Embodiment] [Second Embodiment] [Third Embodiment] [Fourth Embodiment] [Fifth Embodiment] [Sixth Embodiment] [Seventh Embodiment] [Eighth Embodiment] [Ninth Embodiment] [Application Example] [Modification Example]

[0010] [Physical Background] First, in order to facilitate understanding of the present technology, the physical background of the present technology will be described with reference to FIGS. 1 to 3. FIG.

[0011] FIG. 1 is a diagram illustrating an example configuration of a typical rectenna device (rectenna device 1). The rectenna device 1 includes, for example, an antenna element 2 and a rectifier circuit 3. The rectenna device 1 may include a matching circuit (not shown) as needed. An appropriate load 4 is connected to the rectifier circuit 3. Examples of the load 4 include a battery, a communication device, a sensor, and a motor. The rectenna device 1 can generally be applied to electronic devices that include the load 4.

[0012] In the rectenna device 1, the antenna element 2 receives electromagnetic wave energy (hereinafter simply referred to as electromagnetic waves) in space. The antenna element 2 outputs AC power to the rectifier circuit 3. The rectifier circuit 3 rectifies the AC power supplied from the antenna element 2, converts it into DC power, and outputs it to the load 4.

[0013] FIG. 2 is a graph showing the rectification efficiency of the rectenna device 1. In the graph of FIG. 2, the horizontal axis represents input power (dBm), and the vertical axis represents rectification efficiency (%). The rectification efficiency of the rectenna device 1 is defined as the ratio of the DC power output from the rectenna device 1 to the power of the electromagnetic waves input to the antenna element 2. As shown in FIG. 2, in the rectenna device 1, the rectification efficiency gradually increases from a region where the input power is small, but due to the breakdown voltage of the semiconductor element, the rectification efficiency rapidly decreases in a region where the input power is greater than a certain value (for example, around −5 dBm). Possible factors that can cause fluctuations in the input power (electromagnetic wave energy) include fluctuations in the distance between the power transmitting side and the rectenna device, and the use of transmitters with different output powers.

[0014] As shown in FIG. 3A , when a single antenna element 2 is used, power is output over a relatively wide range. On the other hand, as shown in FIG. 3B , when multiple antenna elements 2 are arranged in an array and designed to emit radio waves with the same phase, high power is output in a specific direction (e.g., the front direction). For the same reason, even when the power from the front direction is low, power can be received from the power receiving side. It is expected that such technology of arranging antenna elements 2 in an array will be used as standard for high frequency bands such as millimeter waves. In other words, a rectenna device that can achieve the highest possible rectification efficiency over a wide range of input power while using multiple antenna elements is desired. Taking the above points into consideration, details of the present technology will be described with reference to embodiments.

[0015] 4 is a diagram illustrating an example of the configuration of a rectenna device (rectenna device 100A) according to the first embodiment. Rectenna device 100A is a rectenna device that includes two or more antenna elements (denoted as "ANT" in the diagram), a first rectifier circuit that is provided for each antenna element and rectifies the output of the antenna elements, and a second rectifier circuit that combines the outputs of the two or more antenna elements and allows them to be input and rectifies the combined output, and that performs control to change the number of antenna elements connected to each of the first rectifier circuit and the second rectifier circuit.

[0016] The rectenna device 100A includes, for example, antenna element 10A, antenna element 10B, switch unit (denoted as "SW" in the figure) 11A, switch unit 11B, rectifier circuit 12A, rectifier circuit 12B, rectifier circuit 20, switch unit 21, control unit 40, and output parameter detection unit 41. The rectenna device 100A is connected to a load 30, and DC power generated by the rectenna device 100A is supplied to the load 30. The load 30 can be, for example, a load similar to the load 4 described above.

[0017] The antenna element 10A is a patch antenna, a dipole antenna, a loop antenna, or the like. The antenna element 10A receives electromagnetic waves in space and outputs a high-frequency signal RFA as AC power. Note that, although this specification describes an example of differential transmission of a high-frequency signal (in the figure, the thick dotted line and the thick solid line), the present technology can also be applied to single-ended transmission.

[0018] The switch unit 11A is connected to the output stage (post stage) of the antenna element 10A. The switch unit 11A is a switch that switches the supply destination of the radio frequency signal RFA output from the antenna element 10A. Specifically, the switch unit 11A is connectable to the rectifier circuit 12A and the rectifier circuit 20, and switches the supply destination of the radio frequency signal RFA to the rectifier circuit 12A or the rectifier circuit 20.

[0019] The rectifier circuit 12A is connected to the output stage of the switch unit 11A. When the radio frequency signal RFA is supplied via the switch unit 11A, the rectifier circuit 12A rectifies the radio frequency signal RFA to obtain direct current (DC) power DCA (DC (Direct Current) A). The rectifier circuit 12A outputs this direct current power DCA to the switch unit 21. Note that in this specification, the DC power is shown by two lines, positive and negative (thin dotted and solid lines in the figure), but it can also be shown by a single power transmission line.

[0020] The direct current power DCA output from the rectifier circuit 12A is supplied to the switch unit 21. The rectifier circuit 12A may be configured as an integrated circuit (IC). A known rectifier circuit can be used as the rectifier circuit 12A. For example, a bridge circuit, a voltage doubler circuit, a single shunt circuit, etc. can be used as the rectifier circuit 12A. Semiconductor components used in these rectifier circuits can be selected arbitrarily. Examples of semiconductor components include a Schottky barrier diode, a complementary metal oxide semiconductor (CMOS), and a high electron mobility transistor (HEMT).

[0021] The antenna element 10B is a patch antenna, a dipole antenna, a loop antenna, or the like. The antenna element 10B receives electromagnetic waves in space and outputs a high-frequency signal RFB as AC power. The antenna elements 10A and 10B are, for example, two-dimensionally arranged on the same substrate. In this embodiment, the antenna elements 10A and 10B are connected in parallel.

[0022] The switch unit 11B is connected to the output stage of the antenna element 10B. The switch unit 11B is a switch that switches the supply destination of the high frequency signal RFB output from the antenna element 10B. Specifically, the switch unit 11B is connectable to the rectifier circuit 12B and the rectifier circuit 20, and switches the supply destination of the high frequency signal RFB to the rectifier circuit 12B or the rectifier circuit 20.

[0023] The rectifier circuit 12B is connected to the output stage of the switch unit 11B. When the radio frequency signal RFB is supplied via the switch unit 11B, the rectifier circuit 12B rectifies the radio frequency signal RFB to obtain DC power DCB. The rectifier circuit 12B outputs the DC power DCB to the switch unit 21.

[0024] The DC power DCB output from the rectifier circuit 12B is supplied to the switch unit 21. The rectifier circuit 12B may be configured as an integrated circuit. A known rectifier circuit can be used as the rectifier circuit 12B. For example, a bridge circuit, a voltage doubler circuit, a single shunt circuit, etc. can be used as the rectifier circuit 12B. The semiconductor components used in these rectifier circuits can be selected arbitrarily. Examples of the semiconductor components include a Schottky barrier diode, a CMOS, and a HEMT.

[0025] The rectifier circuit 20 is connected to the output stages of the switch unit 11A and the switch unit 11B. When the radio frequency signal RFA is supplied via the switch unit 11A and the radio frequency signal RFB is supplied via the switch unit 11B, the rectifier circuit 20 rectifies the radio frequency signal RFW, which is a combination of the two signals, to obtain DC power DCW. The rectifier circuit 20 outputs the DC power DCW to the switch unit 21.

[0026] The DC power DCW output from the rectifier circuit 20 is supplied to the switch unit 21. The rectifier circuit 20 may be configured as an integrated circuit. A known rectifier circuit can be used as the rectifier circuit 20. For example, a bridge circuit, a voltage doubler circuit, a single shunt circuit, etc. can be used as the rectifier circuit 20. The semiconductor components used in these rectifier circuits can be selected arbitrarily. Examples of the semiconductor components include a Schottky barrier diode, a CMOS, and a HEMT.

[0027] The switch unit SW21 is connected to the output stages of the rectifier circuit 12A, the rectifier circuit 12B, and the rectifier circuit 20. The switch unit SW21 is a switch that switches the DC power to be supplied to the load 30. When the rectifier circuit 12A supplies DC power DCA and the rectifier circuit 12B supplies DC power DCB, the switch unit 21 outputs DC power that is a combination of both powers to the load 30. When the rectifier circuit 20 supplies DC power DCW, the switch unit 21 outputs the DC power DCW to the load 30.

[0028] The control unit 40 is composed of a CPU (Central Processing Unit) and the like, and performs overall control of the rectenna device 100A. For example, the control unit 40 outputs a switch changeover signal to control the switching of the switch unit 11A, the switch unit 11B, and the switch unit 21. The operations of the switch unit 11A, the switch unit 11B, and the switch unit 21 are controlled in accordance with the switching control by the control unit 40.

[0029] The output parameter detector 41 detects an output parameter corresponding to the input power to the antenna element. Here, the antenna element may be either the antenna element 10A or the antenna element 10B, but it is assumed that the antenna element 10A and the antenna element 10B are disposed close to each other. In other words, considering that there is no significant difference in the input power to the two antenna elements, the output parameter detector 41 may detect an output parameter corresponding to the input power to the antenna element 10A or the antenna element 10B.

[0030] In this embodiment, the magnitude of DC power output from at least one rectifier circuit is detected as an example of an output parameter corresponding to the input power to the antenna element. When the input power to the antenna element is large, the DC power output from the rectifier circuit is large, and when the input power to the antenna element is small, the DC power output from the rectifier circuit is small. In this way, the DC power output from the rectifier circuit changes depending on the input power to the antenna element, so the magnitude of the DC power output from the rectifier circuit can be used as an output parameter. In this embodiment, the output parameter detection unit 41 detects the DC power DCA output from the rectifier circuit 12A as the output parameter. The output parameter detection unit 41 supplies the detection result to the control unit 40.

[0031] The functions of the control unit 40 and the output parameter detection unit 41 may not be functions possessed by the rectenna device 100A, but may be performed by a CPU or the like of an electronic device to which the rectenna device 100A is applied.

[0032] In this embodiment, rectifier circuit 12A and rectifier circuit 12B correspond to an example of a first rectifier circuit provided for each antenna element. Rectifier circuit 20 corresponds to an example of a second rectifier circuit that combines the outputs of antenna element 10A and antenna element 10B and inputs the combined output, and rectifies the combined output. While the three rectifier circuits may have different circuit configurations, the present technology also allows for the use of rectifier circuits having the same circuit configuration. This reduces costs and simplifies the manufacturing process of rectenna device 100A.

[0033] (Example of Operation of Rectenna Device) Next, an example of operation of the rectenna device 100A according to this embodiment will be described. In summary, when the input power to antenna element 10A and antenna element 10B is large, the output of each antenna element is supplied to a first rectifier circuit provided for each antenna element. When the input power to antenna element 10A and antenna element 10B is small, the output of each antenna element is combined and supplied to a second rectifier circuit. Whether the input voltage is large or small is determined by the control unit 40 based on the detection result of the output parameter detection unit 41.

[0034] An exemplary operation will now be described in detail. The output parameter detection unit 41 supplies the detection result of the DC power DCA output from the rectifier circuit 12A to the control unit 40. If the magnitude of the DC power DCA is equal to or greater than a predetermined threshold, the control unit 40 determines that the input voltage to the antenna elements 10A and 10B is high. If the magnitude of the DC power DCA is less than the predetermined threshold, the control unit 40 determines that the input voltage to the antenna elements 10A and 10B is low. In the following description, a case in which the magnitude of the DC power DCA is equal to or greater than the predetermined threshold and the input voltage to the antenna elements 10A and 10B is high will be referred to as a high input power state, and a case in which the magnitude of the DC power DCA is less than the predetermined threshold and the input voltage to the antenna elements 10A and 10B is low will be referred to as a low input power state.

[0035] During high input power, the control unit 40 controls the rectenna device 100A to operate in a high input power operating mode. Specifically, as shown in FIG. 5 , the control unit 40 controls the switch unit 11A so that the radio frequency signal RFA output from the antenna element 10A is supplied to the rectifier circuit 12A. The control unit 40 also controls the switch unit 11B so that the radio frequency signal RFB output from the antenna element 10B is supplied to the rectifier circuit 12B. The control unit 40 then controls the switch unit 21 so that DC power (an example of a first output) obtained by combining the DC power DCA output from the rectifier circuit 12A and the DC power DCB output from the rectifier circuit 12B is supplied to the load 30.

[0036] During low input power, the control unit 40 controls the rectenna device 100A to operate in a low input power operating mode. Specifically, as shown in FIG. 6 , the control unit 40 controls the switch unit 11A so that the radio frequency signal RFA output from the antenna element 10A is supplied to the rectifier circuit 20. Also, as shown in FIG. 6 , the control unit 40 controls the switch unit 11B so that the radio frequency signal RFB output from the antenna element 10B is supplied to the rectifier circuit 20. As a result, the rectifier circuit 20 is supplied with a radio frequency signal RFW obtained by combining the radio frequency signals RFA and RFB. The control unit 40 then controls the switch unit 21 so that the DC power DCW (an example of a second output) obtained by the rectifier circuit 20 rectifying the radio frequency signal RFW is supplied to the load 30.

[0037] By performing the above control, when the input power is small, the number of antenna elements connected to the rectifier circuit 12A is "0", the number of antenna elements connected to the rectifier circuit 12B is "0", and the number of antenna elements connected to the rectifier circuit 20 is "2". Furthermore, when the input power is large, the number of antenna elements connected to the rectifier circuit 12A is "1", the number of antenna elements connected to the rectifier circuit 12B is "1", and the number of antenna elements connected to the rectifier circuit 20 is "0".

[0038] That is, when the magnitude of the DC power DCA is less than a predetermined threshold (when the output parameter is the first output parameter), control is performed to reduce the number of antenna elements connected to each of the rectifier circuits 12A and 12B compared to when the input power is high, and to increase the number of antenna elements connected to the rectifier circuit 20 compared to when the input power is high. Furthermore, when the magnitude of the DC power DCA is equal to or greater than a predetermined threshold (when the output parameter is the second output parameter), control is performed to increase the number of antenna elements connected to each of the rectifier circuits 12A and 12B compared to when the input power is low, and to decrease the number of antenna elements connected to the rectifier circuit 20 compared to when the input power is low. This changes the number of antenna elements connected to each of the rectifier circuits 12A and 12B and the number of antenna elements connected to the rectifier circuit 20. In this manner, in this embodiment, the number of antenna elements connected to each of the first rectifier circuit and the second rectifier circuit is changed depending on the output parameter corresponding to the input power to the antenna elements.

[0039] (Effects Obtained by This Embodiment) The effects obtained by this embodiment will be described with reference to Fig. 7. The horizontal axis of the graph shown in Fig. 7 represents input power (dBm), and the vertical axis represents rectification efficiency (%). Furthermore, line L1 in Fig. 7 represents the rectification efficiency of rectenna device 100A when operating in the small input power operation mode, and line L2 in Fig. 7 represents the rectification efficiency of rectenna device 100A when operating in the large input power operation mode.

[0040] For example, a threshold value for distinguishing between high and low input power is set based on the input power corresponding to the crossing point CP where lines L1 and L2 cross. This allows the operating mode of the rectenna device 100A to be switched to a high input power operating mode at the point where the input power increases and the rectification efficiency begins to decrease on line L1 (near the crossing point CP), thereby suppressing the decrease in rectification efficiency as shown by line L2. Furthermore, the operating mode of the rectenna device 100A can be switched to a low input power operating mode at the point where the input power decreases and the rectification efficiency begins to decrease on line L2 (near the crossing point CP), thereby suppressing the decrease in rectification efficiency as shown by line L1. In other words, even when the input voltage to the rectenna device 100A fluctuates, a rectenna device 100A that can achieve high rectification efficiency over a wide range of input power intensities can be realized.

[0041] (Variation of the First Embodiment) In the above description, the output parameter detection unit 41 detects the magnitude of the DC power DCA output from the rectifier circuit 12A. However, the output parameter detection unit 41 may also detect the magnitude of the DC power DCB output from the rectifier circuit 12B. The output parameter detection unit 41 may also detect the magnitude of the DC power DCW output from the rectifier circuit 20. The output parameter detection unit 41 may also detect the outputs of multiple rectifier circuits, for example, the magnitude of the DC power DCA output from the rectifier circuit 12A and the magnitude of the DC power DCB output from the rectifier circuit 12B. However, because the antenna element 10A and the antenna element 10B are arranged relatively close to each other and there is likely to be no significant difference in the magnitude of the input power, it is preferable from a cost perspective for the output parameter detection unit 41 to detect the output of one of the rectifier circuit 12A and the rectifier circuit 12B.

[0042] The output parameter detected by the output parameter detection unit 41 may not be the DC power output from the rectifier circuit 12A or the like, but may be a DC voltage, a DC current, or the impedance of the rectifier circuit 12A or the like. These DC voltages and the like can also be used as output parameters because they are values ​​that change depending on the input power to the antenna element. The output parameter may also be a parameter related to the load 30. If the load 30 is a motor, an example of the parameter related to the load 30 is the rotational speed of the motor. For example, the motor rotational speed is maintained when the input power is large, and decreases when the input power is small. In other words, the motor rotational speed can also be used as an output parameter because it is a value that changes depending on the input power to the antenna element. In this case, the motor rotational speed is configured to be fed back from the load 30 to the rectenna device 100A, and the output parameter detection unit 41 detects the motor rotational speed by acquiring the fed-back motor rotational speed. The output parameter detection unit 41 then outputs the detection result to the control unit 40. The control unit 40 can determine whether the input power to the antenna element is large or small based on the rotation speed of the motor supplied from the output parameter detection unit 41. If the load 30 is a light-emitting diode, the light emission intensity of the light-emitting diode, the level of the signal flowing through the light-emitting diode, etc. can also be used as parameters related to the load. Furthermore, instead of using one output parameter, a combination of the output parameters exemplified above may be used.

[0043] [Second Embodiment] Next, a second embodiment will be described. In the description of the second embodiment, the same or similar components as those in the above description will be assigned the same reference numerals, and duplicated descriptions will be omitted as appropriate. Furthermore, unless otherwise specified, the matters (configurations, effects, etc.) described in other embodiments can be applied to the second embodiment.

[0044] 8 is a diagram illustrating an example of the configuration of a rectenna device (rectenna device 100B) according to a second embodiment. In this embodiment, a first rectifier circuit and a second rectifier circuit have a common configuration.

[0045] Rectenna device 100B differs from rectenna device 100A in that it does not have switch unit 11A, so that high frequency signal RFA, which is the output of antenna element 10A, is always supplied to rectifier circuit 12A, it does not have rectifier circuit 20, and it is possible to supply the output of switch unit 11B to rectifier circuit 12A. That is, in this embodiment, rectifier circuit 12A has a common configuration with rectifier circuit 20 in the first embodiment.

[0046] When the rectenna device 100B operates in the high input power mode, the operation is substantially the same as that of the rectenna device 100A. That is, during high input power, the radio frequency signal RFA output from the antenna element 10A is supplied to the rectifier circuit 12A. The control unit 40 also controls the switch unit 11B so that the radio frequency signal RFB output from the antenna element 10B is supplied to the rectifier circuit 12B. Then, DC power obtained by combining DC power DCA obtained by rectifying the radio frequency signal RFA with DC power DCB obtained by rectifying the radio frequency signal RFB with the rectifier circuit 12B is supplied to the load 30.

[0047] When the input power is low, i.e., when the rectenna device 100B operates in a low input power mode, the control unit 40 controls the switch unit 11B so that the radio frequency signal RFB is supplied to the rectifier circuit 12A. As a result, the radio frequency signals RFA and RFB are combined in the input stage (preceding stage) of the rectifier circuit 12A to generate the radio frequency signal RFW. The rectifier circuit 12A then rectifies the radio frequency signal RFW to obtain DC power DCW, which is then supplied to the load 30.

[0048] By performing the above control, when the input power is small, the number of antenna elements connected to the rectifier circuit 12A becomes "2," and the number of antenna elements connected to the rectifier circuit 12B becomes "0." Furthermore, when the input power is large, the number of antenna elements connected to the rectifier circuit 12A becomes "1," and the number of antenna elements connected to the rectifier circuit 12B becomes "1."

[0049] The rectenna device 100B of this embodiment can also achieve the same effects as those of Embodiment 1. Furthermore, according to this embodiment, the number of rectifier circuits can be reduced, thereby reducing the cost of the rectenna device 100B.

[0050] In this embodiment, the rectifier circuit 12A and the rectifier circuit 20 have a common configuration, but the rectifier circuit 12B and the rectifier circuit 20 may also have a common configuration.

[0051] [Third Embodiment] Next, a third embodiment will be described. In the description of the third embodiment, the same or similar components as those in the above description will be denoted by the same reference numerals, and duplicated descriptions will be omitted as appropriate. Furthermore, unless otherwise specified, the matters (configurations, effects, etc.) described in other embodiments can be applied to the third embodiment.

[0052] FIG. 9 is a diagram for explaining an example of the configuration of a rectenna device (rectenna device 100C) according to the third embodiment.

[0053] Rectenna device 100C has a configuration in which antenna element 10C, switch unit 11C connected to the output stage of antenna element 10C, rectifier circuit 12C connected to the output stage of switch unit 11C, antenna element 10D, switch unit 11D connected to the output stage of antenna element 10D, and rectifier circuit 12D connected to the output stage of switch unit 11D are added to the configuration of rectenna device 100A. The output stages of switch unit 11C and switch unit 11D are also connected to rectifier circuit 20. In this embodiment, rectifier circuit 12A, rectifier circuit 12B, rectifier circuit 12C, and rectifier circuit 12D correspond to an example of a first rectifier circuit. Furthermore, rectifier circuit 20 corresponds to an example of a second rectifier circuit. In addition, the wiring leading out from each of rectifier circuits 12A, 12B, 12C, and 12D is connected so that the four antenna elements (antenna element 10A, antenna element 10B, antenna element 10C, and antenna element 10D) are connected in parallel.

[0054] The antenna element 10C receives the electromagnetic waves and outputs a high-frequency signal RFC. The rectifier circuit 12C rectifies the high-frequency signal RFC to obtain DC power DCC. The antenna element 10D receives the electromagnetic waves and outputs a high-frequency signal RFD. The rectifier circuit 12D rectifies the high-frequency signal RFD to obtain DC power DCD.

[0055] The output parameter detection unit 41 detects the DC power DCA output from the rectifier circuit 12A and supplies the detection result to the control unit 40. The control unit 40 determines whether the input power to each antenna element is high input power or low input power based on the detection result of the output parameter detection unit 41. The control unit 40 then controls each unit of the rectenna device 100C to operate in an operation mode corresponding to the determination result. Note that the output parameter detection unit 41 may detect the DC power DCB output from the rectifier circuit 12B, may detect the DC power DCC output from the rectifier circuit 12C, or may detect the DC power DCD output from the rectifier circuit 12D.

[0056] An example of the operation of the rectenna device 100C will now be described. When the rectenna device 100C operates in the high input power operating mode, the control unit 40 controls the switch unit 11A so that the radio frequency signal RFA output from the antenna element 10A is supplied to the rectifier circuit 12A. The control unit 40 also controls the switch unit 11B so that the radio frequency signal RFB output from the antenna element 10B is supplied to the rectifier circuit 12B. The control unit 40 also controls the switch unit 11C so that the radio frequency signal RFC output from the antenna element 10C is supplied to the rectifier circuit 12C. The control unit 40 also controls the switch unit 11D so that the radio frequency signal RFD output from the antenna element 10D is supplied to the rectifier circuit 12D. Then, the control unit 40 controls the switch unit 21 so that DC power synthesized from the DC power DCA output from the rectifier circuit 12A, the DC power DCB output from the rectifier circuit 12B, the DC power DCC output from the rectifier circuit 12C, and the DC power DCD output from the rectifier circuit 12D is supplied to the load 30.

[0057] During low input power, the control unit 40 controls the switch unit 11A so that the radio frequency signal RFA output from the antenna element 10A is supplied to the rectifier circuit 20. The control unit 40 also controls the switch unit 11B so that the radio frequency signal RFB output from the antenna element 10B is supplied to the rectifier circuit 20. The control unit 40 also controls the switch unit 11C so that the radio frequency signal RFC output from the antenna element 10C is supplied to the rectifier circuit 20. The control unit 40 also controls the switch unit 11D so that the radio frequency signal RFD output from the antenna element 10D is supplied to the rectifier circuit 20. As a result, the radio frequency signals RFA, RFB, RFC, and RFD are combined at the input stage of the rectifier circuit 20. The combined radio frequency signal RFP is then supplied to the rectifier circuit 20. The control unit 40 then controls the switch unit 21 so that the DC power DCP obtained by the rectifier circuit 20 rectifying the radio frequency signal RFP is supplied to the load 30.

[0058] As a result of the above control, when the rectenna device 100C operates in the small input power operation mode, the number of antenna elements connected to the rectifier circuit 12A is "0," the number of antenna elements connected to the rectifier circuit 12B is "0," the number of antenna elements connected to the rectifier circuit 12C is "0," the number of antenna elements connected to the rectifier circuit 12D is "0," and the number of antenna elements connected to the rectifier circuit 20 is "4." Also, when the rectenna device 100C operates in the large input power operation mode, the number of antenna elements connected to the rectifier circuit 12A is "1," the number of antenna elements connected to the rectifier circuit 12B is "1," the number of antenna elements connected to the rectifier circuit 12C is "1," the number of antenna elements connected to the rectifier circuit 12D is "1," and the number of antenna elements connected to the rectifier circuit 20 is "0." As a result, the number of antenna elements connected to each of rectifier circuits 12A, 12B, 12C, and 12D, and the number of antenna elements connected to rectifier circuit 20 are changed depending on the operating mode of rectenna device 100C.

[0059] The rectenna device 100C of this embodiment can also achieve the same effects as the first embodiment. Furthermore, although the number of rectifier circuits increases according to this embodiment, the transmission line length (wiring length) required to transmit high-frequency signals from each antenna element can be shortened by arranging the rectifier circuits 20 in appropriate positions. In other words, the wiring layout on the board can be simplified, and interference with other wiring (e.g., wiring for communication) can be minimized.

[0060] [Fourth Embodiment] Next, a fourth embodiment will be described. In the description of the fourth embodiment, the same or similar components as those in the above description will be denoted by the same reference numerals, and duplicated descriptions will be omitted as appropriate. Furthermore, unless otherwise specified, the matters (configurations, effects, etc.) described in other embodiments can be applied to the fourth embodiment.

[0061] FIG. 10 is a diagram for explaining an example of the configuration of a rectenna device (rectenna device 100D) according to the fourth embodiment.

[0062] The rectenna device 100D differs from the rectenna device 100C in that the rectifier circuit 12C has a common configuration with the rectifier circuit 20, the rectifier circuit 20 is not present, and the switch unit 21 is not present.

[0063] The operation of rectenna device 100D in the high input power operating mode is substantially the same as that of rectenna device 100C. That is, during high input power operation, control unit 40 controls switch unit 11A so that the high frequency signal RFA output from antenna element 10A is supplied to rectifier circuit 12A. Control unit 40 also controls switch unit 11B so that the high frequency signal RFB output from antenna element 10B is supplied to rectifier circuit 12B. Control unit 40 also controls switch unit 11C so that the high frequency signal RFC output from antenna element 10C is supplied to rectifier circuit 12C. Control unit 40 also controls switch unit 11D so that the high frequency signal RFD output from antenna element 10D is supplied to rectifier circuit 12D. Then, a DC power obtained by combining the DC power DCA obtained by the rectifier circuit 12A rectifying the high frequency signal RFA, the DC power DCB obtained by the rectifier circuit 12B rectifying the high frequency signal RFB, the DC power DCC obtained by the rectifier circuit 12C rectifying the high frequency signal RFC, and the DC power DCD obtained by the rectifier circuit 12D rectifying the high frequency signal RFD is supplied to the load 30.

[0064] When the rectenna device 100D operates in the low input power operating mode, the control unit 40 controls the switch unit 11A so that the radio frequency signal RFA is supplied to the rectifier circuit 12C. The control unit 40 also controls the switch unit 11B so that the radio frequency signal RFB is supplied to the rectifier circuit 12C. The control unit 40 also controls the switch unit 11C so that the radio frequency signal RFC is supplied to the rectifier circuit 12C via a path different from that used during high input power. The control unit 40 also controls the switch unit 11D so that the radio frequency signal RFD is supplied to the rectifier circuit 12D. As a result, the radio frequency signals RFA, RFB, RFC, and RFD are combined at the input stage of the rectifier circuit 12C to generate the radio frequency signal RFP. The DC power DCP obtained by rectifying the radio frequency signal RFP by the rectifier circuit 12C is supplied to the load 30.

[0065] As a result of the above control, when rectenna device 100D operates in the small input power operation mode, the number of antenna elements connected to rectifier circuit 12C becomes "4," and the number of antenna elements connected to each of rectifier circuits 12A, 12B, and 12D becomes "0." Also, when rectenna device 100D operates in the large input power operation mode, the number of antenna elements connected to rectifier circuit 12A becomes "1," the number of antenna elements connected to rectifier circuit 12B becomes "1," the number of antenna elements connected to rectifier circuit 12C becomes "1," and the number of antenna elements connected to rectifier circuit 12D becomes "1."

[0066] The rectenna device 100D of this embodiment can also achieve the same effects as those of Embodiment 1. Furthermore, according to this embodiment, the number of rectifier circuits can be reduced, thereby reducing the cost of the rectenna device 100D.

[0067] In this embodiment, the rectifier circuit 12C and the rectifier circuit 20 have a common configuration, but any one of the rectifier circuits 12A, 12B, and 12D may have a common configuration with the rectifier circuit 20.

[0068] Although the switch unit 11C may be omitted, in this embodiment, the path through which the high-frequency signal RFC is supplied to the rectifier circuit 12C during high input power operation and the path through which the high-frequency signal RFC is supplied to the rectifier circuit 12C during low input power operation are separate paths. For example, the transmission line length of the path through which the high-frequency signal RFC is supplied to the rectifier circuit 12C during low input power operation is set longer than the transmission line length of the path through which the high-frequency signal RFC is supplied to the rectifier circuit 12C during high input power operation. This makes it possible to adjust the length of the latter transmission line, making it easier to adjust the length of the transmission line so that the output from each antenna and the input to the rectifier circuit 20 are approximately in phase. Specific examples of phase alignment will be described later.

[0069] [Fifth Embodiment] Next, a fifth embodiment will be described. In the description of the fifth embodiment, the same or similar components as those in the above description will be denoted by the same reference numerals, and duplicated descriptions will be omitted as appropriate. Furthermore, unless otherwise specified, the matters (configurations, effects, etc.) described in other embodiments can be applied to the fifth embodiment.

[0070] FIG. 11 is a diagram for explaining an example of the configuration of a rectenna device (rectenna device 100E) according to the fifth embodiment.

[0071] The configuration and operation of rectenna device 100E are substantially the same as those of rectenna device 100C described in the third embodiment. The only difference is the connection topology of the four antenna elements. As shown in FIG. 11 , in this embodiment, the wiring extending from rectifier circuit 12A, rectifier circuit 12B, rectifier circuit 12C, and rectifier circuit 12D is connected so that the four antenna elements (antenna element 10A, antenna element 10B, antenna element 10C, and antenna element 10D) are connected in a two-in-series, two-in-parallel configuration. In this way, the connection topology of the multiple antenna elements can be changed as appropriate.

[0072] The rectenna device 100E of this embodiment can also achieve the same effects as those of the first embodiment. Furthermore, in this embodiment, the number of antenna elements connected in series is equal to the number of antenna elements connected in parallel, which provides the advantage of simplifying the design.

[0073] As shown in FIG. 12, in a rectenna device 100E, for example, the rectifier circuit 12C and the rectifier circuit 20 may have a common configuration, as described in the third embodiment.

[0074] [Sixth Embodiment] Next, a sixth embodiment will be described. In the description of the sixth embodiment, the same or similar components as those in the above description will be denoted by the same reference numerals, and duplicated descriptions will be omitted as appropriate. Furthermore, unless otherwise specified, the matters (configurations, effects, etc.) described in other embodiments can be applied to the sixth embodiment.

[0075] 13 is a diagram illustrating an example of the configuration of a rectenna device (rectenna device 100F) according to a sixth embodiment. This embodiment is an example of a rectenna device in which the connection topology of antenna elements is changeable.

[0076] The rectenna device 100F has a configuration in which a connection mode changeover switch unit 51A, a connection mode changeover switch unit 51B, a connection mode changeover switch unit 52A, and a connection mode changeover switch unit 52B are added to the rectenna device 100C (see Figure 9) described in the third embodiment.

[0077] 13, the connection mode changeover switch unit 51A is provided between the output stage of the rectifier circuit 12A and the output stage of the rectifier circuit 12C. The connection mode changeover switch unit 51B is provided between the output stage of the rectifier circuit 12B and the output stage of the rectifier circuit 12D. The connection mode changeover switch unit 52A is provided between the output stage of the switch unit 11A and the output stage of the switch unit 11B. The connection mode changeover switch unit 52B is provided between the output stage of the switch unit 11C and the output stage of the switch unit 11D.

[0078] In this embodiment, for example, the connection mode of four antenna elements can be switched between a four-parallel connection or a two-series / two-parallel connection. When the connection mode of the four antenna elements is set to a four-parallel connection, each connection mode changeover switch unit operates to achieve the connection shown in Fig. 10. When the connection mode of the four antenna elements is set to a two-parallel / two-series connection, each connection mode changeover switch unit operates to achieve the connection shown in Fig. 11.

[0079] Each connection mode changeover switch unit may be configured to automatically switch in response to switching control by the control unit 40, or may be configured to be manually switched.

[0080] The rectenna device 100F of this embodiment can also achieve the same effects as those of the first embodiment. Furthermore, depending on the load 30, changing the connection mode of each antenna element to change the voltage output from the switch unit 21 can suppress reflections between the load 30 and the rectenna device 100F, thereby achieving high efficiency for the rectenna device 100F. Since there is a load value that optimizes efficiency depending on the wiring configuration of the rectenna device 100F, appropriately changing the connection mode of the antenna elements can match the load and reduce reflections. Furthermore, when considering applications such as battery charging, the optimal load value fluctuates, and appropriately changing the connection mode of the antenna elements can adapt the output of the rectenna device 100F to the fluctuations in the load value.

[0081] [Seventh Embodiment] Next, a seventh embodiment will be described. In the description of the seventh embodiment, the same or similar components as those in the above description will be denoted by the same reference numerals, and duplicated descriptions will be omitted as appropriate. Furthermore, unless otherwise specified, the matters (configurations, effects, etc.) described in other embodiments can be applied to the seventh embodiment.

[0082] In each of the above-described embodiments, when the rectenna device operates in the small input power mode, the high-frequency signals output from each antenna element are combined and input to a second rectifier circuit (for example, rectifier circuit 20 or a rectifier circuit having a common configuration with rectifier circuit 20). When the length of the transmission line transmitting the high-frequency signal to the second rectifier circuit becomes long, the impedance cannot be ignored. This embodiment addresses this issue.

[0083] In the rectenna device (rectenna device 100G) according to this embodiment, the output from each antenna element and the input to the second rectifier circuit (e.g., rectifier circuit 20) are made to be approximately in phase (the phase difference is an integer multiple of approximately 360 degrees). One method for achieving this is to adjust the length of the transmission line between each antenna element and the second rectifier circuit. For example, as in the above-described rectenna device 100D (see FIG. 10 ), the length of the transmission line through which the high-frequency signal RFC is transmitted at low input power can be intentionally increased to adjust the length of the transmission line, and impedance matching can be achieved by appropriately setting the length of the transmission line.

[0084] Alternatively, a matching circuit for impedance matching may be provided at the input stage of the second rectifier circuit. For example, as shown in Fig. 14, a rectenna device 100G may have a configuration in which a matching circuit 55 is provided at the input stage of the rectifier circuit 20 of the rectenna device 100C described in the third embodiment.

[0085] Furthermore, a phase shifter may be provided on the transmission line through which the high-frequency signal output from each antenna element is transmitted when the input power is low. For example, as shown in FIG. 15 , a phase shifter 56A is provided between the switch unit 11A and the rectifier circuit 20, a phase shifter 56B is provided between the switch unit 11B and the rectifier circuit 20, a phase shifter 56C is provided between the switch unit 11C and the rectifier circuit 20, and a phase shifter 56D is provided between the switch unit 11D and the rectifier circuit 20. Each phase shifter operates so that the output from each antenna element and the input to the rectifier circuit 20 are substantially in phase (the phase difference is an integer multiple of approximately 360 degrees). Furthermore, in the configuration shown in FIG. 15 , the phase between each antenna element is adjusted, allowing the rectenna device 100G to receive high power even if the position of the power transmitter changes due to a change in directivity.

[0086] The rectenna device 100G of this embodiment can also achieve the same effects as those of the first embodiment. Furthermore, reflections due to impedance mismatch can be prevented, and the rectenna device 100G can achieve high conversion efficiency overall.

[0087] [Eighth Embodiment] Next, an eighth embodiment will be described. In the description of the eighth embodiment, the same or similar components as those in the above description will be denoted by the same reference numerals, and duplicated descriptions will be omitted as appropriate. Furthermore, unless otherwise specified, the matters (configurations, effects, etc.) described in other embodiments can be applied to the eighth embodiment.

[0088] FIG. 16 is a diagram illustrating an example configuration of a rectenna device (rectenna device 100H) according to an eighth embodiment. In the above-described embodiments, a first rectifier circuit (e.g., rectifier circuit 12A, rectifier circuit 12B, rectifier circuit 12C, and rectifier circuit 12D) is provided for each antenna element. However, a first rectifier circuit may be provided for each antenna element group consisting of multiple antenna elements. For example, a first rectifier circuit may be provided for each antenna element group consisting of four antenna elements. In the case of the rectenna device 100H shown in FIG. 16 , for example, antenna element 60A, antenna element 61A, antenna element 62A, and antenna element 63A form one antenna element group 64A. A rectifier circuit 12A is provided for this antenna element group 64A. Furthermore, antenna element 60B, antenna element 61B, antenna element 62B, and antenna element 63B form one antenna element group 64B. A rectifier circuit 12B is provided for this antenna element group 64B. Furthermore, antenna element 60C, antenna element 61C, antenna element 62C, and antenna element 63C form one antenna element group 64C. A rectifier circuit 12C is provided for this antenna element group 64C. Furthermore, antenna element 60D, antenna element 61D, antenna element 62D, and antenna element 63D form one antenna element group 64D. A rectifier circuit 12D is provided for this antenna element group 64D.

[0089] When the rectenna device 100H operates in the high input power operating mode, the control unit 40 performs switching control so that a high-frequency signal obtained by combining high-frequency signals output from four antenna elements is supplied to the first rectifier circuits corresponding to the four antenna elements. For example, a high-frequency signal RFAA obtained by combining high-frequency signals output from antenna element group 64A, i.e., four antenna elements (antenna element 60A, antenna element 61A, antenna element 62A, and antenna element 63A), is supplied to the switch unit 11A. The switch unit 11A switches in response to the switching control of the control unit 40, and the high-frequency signal RFAA is supplied to the rectifier circuit 12A via the switch unit 11A. The rectifier circuit 12A obtains DC power DCAA by rectifying the high-frequency signal RFAA from the switch unit 11A.

[0090] Furthermore, a high frequency signal RFBB obtained by combining high frequency signals output from antenna element group 64B, i.e., four antenna elements (antenna element 60B, antenna element 61B, antenna element 62B, and antenna element 63B), is supplied to switch unit 11B. Switch unit 11B switches in accordance with switching control of control unit 40, and the high frequency signal RFBB is supplied to rectifier circuit 12B via switch unit 11B. Rectifier circuit 12B obtains DC power DCBB by rectifying the high frequency signal RFBB supplied from switch unit 11B.

[0091] Furthermore, a high frequency signal RFCC obtained by combining high frequency signals output from antenna element group 64C, i.e., four antenna elements (antenna element 60C, antenna element 61C, antenna element 62C, and antenna element 63C), is supplied to switch unit 11C. Switch unit 11C switches in accordance with switching control of control unit 40, and the high frequency signal RFCC is supplied to rectifier circuit 12C via switch unit 11C. Rectifier circuit 12C obtains DC power DCCC by rectifying the high frequency signal RFCC supplied from switch unit 11C.

[0092] Furthermore, a high-frequency signal RFDD obtained by combining high-frequency signals output from antenna element group 64D, i.e., four antenna elements (antenna element 60D, antenna element 61D, antenna element 62D, and antenna element 63D), is supplied to switch unit 11D. Switch unit 11D switches in accordance with switching control by control unit 40, and the high-frequency signal RFDD is supplied to rectifier circuit 12D via switch unit 11D. Rectifier circuit 12D obtains DC power DCDD by rectifying the high-frequency signal RFDD supplied from switch unit 11D. Then, control unit 40 controls switch unit 21 so that DC power obtained by combining DC power DCAA, DC power DCBB, DCCC, and DCDD is supplied to load 30.

[0093] When the rectenna device 100H operates in the small input power operation mode, the control unit 40 performs switching control on each switch unit (switch unit 11A, switch unit 11B, switch unit 11C, and switch unit 11D) so that a high-frequency signal obtained by combining the high-frequency signals output from the 16 antenna elements is supplied to the rectifier circuit 20. In response to this switching control, a high-frequency signal RFPP obtained by combining the high-frequency signals output from the 16 antenna elements is supplied to the rectifier circuit 20. The rectifier circuit 20 rectifies the high-frequency signal RFPP to obtain DC power DCPP. The control unit 40 then controls the switch unit 21 so that the DC power DCPP is supplied to the load 30.

[0094] In this way, the rectenna device according to the present technology may be configured to operate in units of antenna element groups. For example, in the case of millimeter waves, the physical size of the antenna elements is small, so the number of antenna elements on the rectenna device side (power receiving side) can be increased. Therefore, by utilizing subarrays (antenna element groups), it becomes possible to accommodate a wider input power range. For example, if there are a total of 16 elements, the antenna element groups can be configured not only for each element but also for groups of four elements, and the outputs of the 16 elements can be combined and used during low input power operation, ideally, a gain improvement of 12 dB can be expected.

[0095] When the number of antenna elements and the connection mode of the antenna elements in this embodiment are generalized, a certain set of integers N １ , N ２ ..., N ｍ and the number of antenna elements is Σ ｉ N ｉ ２ , and each N ｉ ２ The connection state of the antenna elements is N ｉ Series N ｉ It is preferable that the rectenna device be configured in parallel. With this configuration, the impedance of the antenna element and the impedance of the antenna element group can be made approximately the same. In other words, matching can be achieved, thereby achieving high efficiency in the rectenna device. Furthermore, the design of the rectenna device can be simplified, reducing the effort required for designing the rectenna device.

[0096] [Ninth Embodiment] Next, a ninth embodiment will be described. In the description of the ninth embodiment, the same or similar components as those in the above description will be denoted by the same reference numerals, and duplicated descriptions will be omitted as appropriate. Furthermore, unless otherwise specified, the matters (configurations, effects, etc.) described in other embodiments can be applied to the ninth embodiment.

[0097] 17A and 17B are diagrams illustrating an example of the configuration of a rectenna device (rectenna device 100J) according to the ninth embodiment. The rectenna device 100J has a configuration similar to that of the rectenna device 100A described above. The rectenna device 100J also has a substrate (main board) 71 on which the components of the rectenna device 100J are mounted. The components of the rectenna device 100J are detachably attached to the substrate 71. The block detachably attached to the rectenna device 100J may be a block consisting of a single component, or may be a block including multiple components.

[0098] As an example, one block is formed by one antenna element and components that output high-frequency signals and DC power. Specifically, as shown in FIG. 17A , block 72A is formed by antenna element 10A, switch unit 11A, and rectifier circuit 12A. Block 72A is detachable from substrate 71. As shown in FIG. 17B , when block 72A is attached to substrate 71, the wiring of block 72A and the wiring of substrate 71 are appropriately connected. Furthermore, block 72B is formed by antenna element 10B, switch unit 11B, and rectifier circuit 12B. Block 72B is detachable from substrate 71. As shown in FIG. 17B , when block 72B is attached to substrate 71, the wiring of block 72B and the wiring of substrate 71 are appropriately connected.

[0099] One block may be composed of one component of the rectenna device 100J, for example, as shown in Fig. 18A, block 72A may be composed of antenna element 10A, and blocks 72B to 10B may be composed of antenna elements 10B. Note that the operation after each block is mounted on the substrate 71 is the same as that of the rectenna device 100A.

[0100] According to this embodiment, the rectenna device 100J can be sized appropriately for the equipment to which it is applied, even under limitations such as area and weight. The substrate 71 may also be cuttable as needed. Furthermore, as shown in FIG. 18A , when one block is composed of one antenna element, the antenna elements in each block may not be the same antenna element but may be different types of antenna elements. This allows customization of the rectenna device to accommodate different polarizations and electromagnetic wave incidence angles.

[0101] [Application Examples] Specific application examples of the rectenna device according to the present technology will be described.

[0102] 19A to 19J show specific examples of electronic devices to which the rectenna device according to the present technology can be applied. As shown in FIG. 19A , the rectenna device according to the present technology can be applied to, for example, a smartphone. As shown in FIG. 19B , the rectenna device according to the present technology can be applied to, for example, a wireless earphone. As shown in FIG. 19C , the rectenna device according to the present technology can be applied to, for example, a glasses-type terminal for VR (Virtual Reality). As shown in FIG. 19D , the rectenna device according to the present technology can be applied to, for example, a smartwatch. As shown in FIG. 19E , the rectenna device according to the present technology can be applied to, for example, a controller for a game device. As shown in FIG. 19F , the rectenna device according to the present technology can be applied to, for example, a television device.

[0103] The rectenna device according to the present technology can also be applied to moving bodies. As shown in FIG. 19G, the rectenna device according to the present technology can be applied to, for example, a ship. As shown in FIG. 19H, the rectenna device according to the present technology can be applied to, for example, an air vehicle such as a drone. As shown in FIG. 19I, the rectenna device according to the present technology can be applied to, for example, an autonomously mobile robot (the illustrated example is a dog-type robot). As shown in FIG. 19J, the rectenna device according to the present technology can be applied to, for example, an autonomous cleaning robot. In addition to the examples shown in the drawings, the rectenna device according to the present technology can also be mounted on sensing devices having sensors (for example, vital sensors that measure human biometric information (heart rate, body temperature, blood pressure, etc.) and environmental sensors that measure environmental information), external devices with USB output, and various wearable devices.

[0104] (Specific System Configuration Example) A specific system configuration example to which the rectenna device according to the present technology can be applied and an example of processing performed in the system will be described. 20 and 21 show one form of a power transmitting and receiving system (power transmitting and receiving system 80) according to the present technology. The power transmitting and receiving system 80 includes, for example, a power transmitter 81 and a smartphone 82. A rectenna device according to the present technology, for example, the rectenna device 100A described in the first embodiment, is built into the smartphone 82. Of course, a rectenna device other than the rectenna device 100A, such as the rectenna device 100B, may also be applied to the smartphone 82. Note that when any of the above-described rectenna devices, rectenna device 100A, rectenna device 100B, . . . rectenna device 100J, can be used, they will be collectively referred to as rectenna device 100, as appropriate.

[0105] The power transmitter 81 is a power transmitting router or the like that emits electromagnetic waves. The rectenna device 100A built into the smartphone 82 receives the electromagnetic waves output from the power transmitter 81. As shown in FIG. 20 , when the distance between the power transmitter 81 and the smartphone 82 is long (for example, the distance between the power transmitter 81 and the smartphone 82 is x meters), the electromagnetic waves received by the rectenna device 100A are small. Therefore, the rectenna device 100A operates in a low-input power mode. On the other hand, as shown in FIG. 21 , when the distance between the power transmitter 81 and the smartphone 82 is short (for example, the distance between the power transmitter 81 and the smartphone 82 is y meters (where x > y)), the electromagnetic waves received by the rectenna device 100A are large. Therefore, the rectenna device 100A operates in a high-input power operating mode.

[0106] 22 is a block diagram showing an example configuration of an electronic device (electronic device 90) to which the rectenna device 100 is applied. In addition to the rectenna device 100, the electronic device 90 has a voltage detection unit 85, a DC-DC converter 86, a power supply circuit 87, and a load 88. The voltage detection unit 85 is connected to the output stage of the rectenna device 100. The DC-DC converter 86 is connected to the output stage of the voltage detection unit 85. The power supply circuit 87 is connected to the output stage of the DC-DC converter 86. The load 88 is connected to the output stage of the power supply circuit 87.

[0107] The voltage detection unit 85 detects the voltage output by at least one first rectifier circuit in the rectenna device 100. The voltage detected by the voltage detection unit 85 is fed back to the rectenna device 100. The rectenna device 100 switches between a low-input power operating mode and a high-input power operating mode based on the fed-back voltage. In other words, the voltage detection unit 85 corresponds to an example of the output parameter detection unit 41 described above. Note that in the above-described embodiment, a configuration example in which the rectenna device 100 includes the output parameter detection unit 41 has been described. However, as in this example, a component corresponding to the output parameter detection unit 41 may be provided in the output stage of the rectenna device 100. In other words, the rectenna device 100 may be configured without including the output parameter detection unit 41.

[0108] The DC-DC converter 86 is a buck-boost converter that boosts or bucks the output of the rectenna device 100. When the rectenna device 100 operates in a small input power operating mode, that is, when the second output from the second rectifier circuit is output from the rectenna device 100, the DC-DC converter 86 boosts the second output. Even when the input power to the rectenna device 100 is small, the rectenna device 100 according to the present technology can achieve high conversion efficiency. However, the total DC power output from the rectenna device 100 can be smaller than when the input power is large. Therefore, by boosting the second output from the rectenna device 100 using the DC-DC converter 86, stable operation of the load 88 is possible.

[0109] On the other hand, when the rectenna device 100 operates in the high input power operating mode, that is, when the rectenna device 100 outputs a first output obtained by combining the outputs of the multiple first rectifier circuits, the DC-DC converter 86 steps down the first output. When the rectenna device 100 operates in the high input power operating mode, the first output output from the rectenna device 100 may become excessive due to the load 88. Therefore, by using the DC-DC converter 86 to step down the first output from the rectenna device 100, stable operation of the load 88 is possible. Note that the rectenna device 100 may be configured to include the DC-DC converter 86 according to this example. In this case, the DC-DC converter 86 is provided, for example, in the output stage of the switch unit 21.

[0110] The power supply circuit 87 is for stabilizing the output voltage and output current. A known power supply circuit can be used as the power supply circuit 87. The output from the power supply circuit 87 is supplied to a load 88. The load 88 is a load corresponding to the electronic device to which the rectenna device 100 is applied.

[0111] 23 is a block diagram illustrating an example of a power transmitting and receiving system configured with a power transmitter and an electronic device to which a rectenna device 100 is applied. The power transmitting and receiving system shown in FIG. 23 includes a power transmitter 200A and an electronic device 300A.

[0112] The power transmitter 200A in this example has a power transmitter IC 201 that controls the power transmitter 200A in an overall manner, a power transmitting antenna 202 that emits electromagnetic waves in accordance with the control of the power transmitter IC 201, and a communication module 203 that communicates with external devices.

[0113] The electronic device 300A according to this example is, for example, a sensing device. In addition to the rectenna device 100, voltage detection unit 85, DC-DC converter 86, and power supply circuit 87 described above, the electronic device 300A also has a sensor 301 and a communication module 302 (an example of a communication unit) that communicates with external devices. The sensor 301 and communication module 302 operate using power supplied from the power supply circuit 87. In this example, the load 88 described above corresponds to the sensor 301.

[0114] The sensing data acquired by the sensor 301 is transmitted from the communication module 302 to the power transmitter 200A. Examples of the sensing data include sensing data of biological information, sensing data of environmental information, etc. In addition to the sensing data, information on the power output from the rectenna device 100 may also be included in the data transmitted to the power transmitter 200A.

[0115] The sensing data transmitted from the electronic device 300A is received by the communication module 203 of the power transmitter 200A. The power transmitter 200A may transmit the received sensing data to another device using the communication module 203. Examples of the other device include a cloud server, an electronic device owned by the same user as the user of the electronic device 300A, and the like.

[0116] Fig. 24 is a block diagram illustrating another power transmitting and receiving system. The power transmitting and receiving system shown in Fig. 24 includes a power transmitter 200B and an electronic device 300B. In this example, the electronic device 300B has a communication module 302 that communicates with the power transmitter 200B, and the operation mode is switched between a high input power operation mode and a low input power operation mode depending on the content of communication by the communication module 302. That is, in this example, control is performed to change the number of antenna elements connected to the first rectifier circuit and the second rectifier circuit depending on the content of communication by the communication module 302.

[0117] The power transmitter 200B according to this example has the same configuration as, for example, the power transmitter 200A. The electronic device 300B according to this example has a configuration in which, for example, the voltage detection unit 85 is not included and a power receiving side IC 305 is added to the configuration of the electronic device 300A.

[0118] In this example, communication is performed between the power transmitter 200B and the electronic device 300B. For example, the power transmitter 200B and the electronic device 300B transmit and receive position information and the charging status of a battery (not shown) to each other. The battery is charged by the output of a power supply circuit 87, for example, and the power output from the battery is supplied to a load 88.

[0119] For example, position information is transmitted and received between power transmitter 200B and electronic device 300B. If, as a result of the communication, power transmitter 200B and electronic device 300B are located close to each other, power transmitter 200B reduces the radiation output of electromagnetic waves to prevent excessive power supply from adversely affecting rectenna device 100 and load 88. Furthermore, in rectenna device 100 of electronic device 300B, control unit 40 performs switching control on each switch unit so that the rectenna device operates in a low-input power operation mode. As described in the first embodiment and the like, the number of antenna elements connected to the first rectifier circuit and the second rectifier circuit is changed in accordance with this switching control.

[0120] Then, after the electronic device 300B confirms that there are no problems with safety or the like in terms of power, the electronic device 300B notifies the power transmitter 200B of this fact. Furthermore, in response to control by the power receiving side IC 305, the control unit 40 performs switching control on each switch unit so that the rectenna device 100 operates in a high input power operating mode. As described in the first embodiment and the like, the number of antenna elements connected to the first rectifier circuit and the second rectifier circuit is changed in response to this switching control. Then, upon receiving the notification, the power transmitter 200B increases the radiation output of the electromagnetic waves and emits them. This allows the power transmitter 200B to safely transmit the maximum possible power to the electronic device 300B.

[0121] Also, in electronic device 300B, suppose that power receiving IC 305 determines that the operation of load 88 will not be affected even if the battery charging rate is slow. In this case, power receiving IC 305 controls communication module 302 to notify power transmitter 200B that the input power to rectenna device 100 may be small. Then, rectenna device 100 performs switching control on each switch unit so that the device operates in a low-input-power operating mode. Furthermore, upon receiving the notification, power transmitter 200B reduces the radiation output of electromagnetic waves. This reduces losses on the power transmitting side and enables efficient power transmission.

[0122] FIG. 25 is a flowchart showing a specific example of the flow of processing performed in the power transmitting and receiving system shown in FIG.

[0123] In step ST11, the electronic device 300B notifies the power transmitter 200B by communication that the charge of the battery of the electronic device 300B is insufficient. Then, the process proceeds to steps ST12 and ST13.

[0124] In step ST12, the power transmitter IC 201 performs control to increase the radiation output of the electromagnetic waves radiated from the power transmitter 200B. By this control, the radiation output of the electromagnetic waves radiated from the power transmitting antenna 202 increases.

[0125] In step ST13, the power receiving side IC 305 instructs the rectenna device 100 to perform switching control to switch each switch unit so that the rectenna device 100 operates in the large input power operating mode. In response to this instruction, the rectenna device 100 performs switching control and operates in the large input power operating mode. The power receiving side IC 305 then monitors whether the battery is sufficiently charged. Following steps ST12 and ST13, the process proceeds to step ST14.

[0126] In step ST14, for example, when the battery of the electronic device 300B is sufficiently charged, the electronic device 300B notifies the power transmitter 200B of this fact by communication. Then, the process proceeds to steps ST15 and ST16.

[0127] In step ST15, the power transmitter IC 201 performs control to reduce the radiation output of the electromagnetic waves radiated from the power transmitter 200B. By this control, the radiation output of the electromagnetic waves radiated from the power transmitting antenna 202 is reduced.

[0128] Furthermore, in step ST16, the power receiving side IC 305 instructs the rectenna device 100 to perform switching control to switch each switch unit so that the rectenna device 100 operates in the small input power operation mode. In response to this instruction, the rectenna device 100 performs switching control and operates in the small input power operation mode. By performing the processing described above, the radiation output of the electromagnetic waves from the power transmitting side is adjusted according to the power required by the electronic device 300B on the power receiving side, thereby reducing electromagnetic wave loss and enabling efficient power transmission.

[0129] Furthermore, transmitting the detected output (e.g., DC power) of the rectenna device from the receiving electronic device to the transmitting power transmitter can provide the following advantages. For example, if the distance between the receiving electronic device and the power transmitter is known, the power transmitter can estimate the surrounding environment by feeding back the output detected by the electronic device to the power transmitter. For example, if the output fed back is small relative to the distance, the power transmitter can determine that the surrounding environment is one in which electromagnetic waves are likely to be blocked or reflected. In this case, the power transmitter may increase the radiation output of the electromagnetic waves or change the directivity. Furthermore, if the influence of the surrounding environment is small, the distance between the electronic device and the power transmitter can also be estimated based on the output detected by the electronic device.

[0130] [Modifications] Although the embodiments of the present technology have been specifically described above, the content of the present technology is not limited to the above-described embodiments, and various modifications based on the technical ideas of the present technology are possible.

[0131] The components constituting the rectenna device may be arranged three-dimensionally (3D). For example, as shown in FIG. 26 , antenna elements, switches connected to the antenna elements, and first rectifier circuits (rectifier circuits 12A, 12B, 12C, and 12D are shown in the illustrated example) may be arranged on at least two surfaces of a cubic substrate 95. In such a configuration, it is conceivable that the input power to each antenna element may differ depending on the direction of incidence of the electromagnetic waves. In such a case, as described in the embodiment, switching control is performed according to the input power to the antenna elements, thereby achieving optimal efficiency.

[0132] Furthermore, as described in the eighth embodiment, when a first rectifier circuit is provided for each group of antenna elements, the number of antenna elements connected to (supplied with signals from) the second rectifier circuit may be changed according to a plurality of threshold values ​​set for the output parameters.

[0133] FIG. 27 is a diagram showing an example of the configuration of a rectenna device according to this modified example. The rectenna device shown in FIG. 27 has an antenna element group circuit including an antenna element group and its peripheral circuits. For example, the rectenna device shown in FIG. 27 has four antenna element group circuits (antenna element group circuit 96A, antenna element group circuit 96B, antenna element group circuit 96C, and antenna element group circuit 96D). In this modified example, the four antenna element group circuits have the same configuration. However, there may be differences in configuration among the individual antenna element group circuits. In the following description, when there is no need to distinguish between the individual antenna element group circuits, they will be collectively referred to as antenna element group circuit 96 as appropriate.

[0134] The antenna element group circuit 96 has terminals TA and TB. RF signals output from one or more antenna elements included in the antenna element group circuit 96 are output from the terminals TA and TB. The RF signals output from the antenna element group circuits 96 are combined and supplied to the rectifier circuit 20. The antenna element group circuit 96 also has terminals TC and TD. Direct current power DC obtained by rectifying the RF signals output from one or more antenna elements included in the antenna element group circuit 96 is output from the terminals TC and TD.

[0135] 28 is a diagram showing a configuration example of the antenna element group circuit 96. The antenna element group circuit 96 has antenna elements 97A, 97B, 97C, and 97D. In this modification, the antenna element group is configured by these four antenna elements.

[0136] A switch unit 98A is connected to the output stage of the antenna element 97A. A rectifier circuit 99A and terminals TA and TB are connected to the output stage of the switch unit 98A. Terminals TC and TD are connected to the output stage of the rectifier circuit 99A. The switch unit 98A switches the supply destination of the RF signal output from the antenna element 97A between terminals TA and TB or the rectifier circuit 99A. The switch unit 98A is also configured so that the switch included in the switch unit 98A can be connected to, for example, ground. When the switch unit 98A is connected to ground, the RF signal output from the antenna element 97A can be prevented from being output to a stage subsequent to the switch unit 98A.

[0137] Furthermore, a switch unit 98B is connected to the output stage of the antenna element 97B. A rectifier circuit 99B and terminals TA and TB are connected to the output stage of the switch unit 98B. Terminals TC and TD are connected to the output stage of the rectifier circuit 99B. The switch unit 98B switches the supply destination of the RF signal output from the antenna element 97B between terminals TA and TB or the rectifier circuit 99B. The switch unit 98B is also configured so that a switch included in the switch unit 98B can be connected to, for example, ground. When the switch unit 98B is connected to ground, the RF signal output from the antenna element 97B cannot be output to a stage subsequent to the switch unit 98B.

[0138] Furthermore, a switch unit 98C is connected to the output stage of the antenna element 97C. A rectifier circuit 99C and terminals TA and TC are connected to the output stage of the switch unit 98C. Terminals TC and TD are connected to the output stage of the rectifier circuit 99C. The switch unit 98C switches the supply destination of the RF signal output from the antenna element 97C between terminals TA and TB, or the rectifier circuit 99C. The switch unit 98C is also configured so that the switch included in the switch unit 98C can be connected to, for example, ground. When the switch unit 98C is connected to ground, the RF signal output from the antenna element 97C can be prevented from being output to a stage subsequent to the switch unit 98C.

[0139] A switch unit 98D is connected to the output stage of the antenna element 97D. A rectifier circuit 99D and terminals TA and TB are connected to the output stage of the switch unit 98D. Terminals TC and TD are connected to the output stage of the rectifier circuit 99D. The switch unit 98D switches the supply destination of the RF signal output from the antenna element 97D between terminals TA and TB or the rectifier circuit 99D. The switch unit 98D is also configured so that its switch can be connected to, for example, ground. When the switch unit 98D is connected to ground, the RF signal output from the antenna element 97D cannot be output to a stage subsequent to the switch unit 98D. Note that switching control of each of the switch units 98A, 98B, 98C, and 98D is performed by, for example, the control unit 40.

[0140] An example of the operation of the rectenna device according to this modification will be described. For example, when the DC power output from an antenna element is a large input power greater than the threshold value Ta, it is not necessary to use the outputs of all four antenna elements. Therefore, the antenna element group circuit 96 selects one antenna element and outputs the output of the selected antenna element to the corresponding first rectifier circuit. For example, the antenna element group circuit 96 controls the switching of the switch unit 98A so that the RF signal from the antenna element 97A is supplied to the rectifier circuit 99A. The antenna element group circuit 96 also controls the switching of the switch units 98B, 98C, and 98D so that the RF signals from the antenna elements 97B, 97C, and 97D are not output to subsequent stages. In response to this control, the RF signal from the antenna element 97A is rectified by the rectifier circuit 99A, and DC power DC obtained is output from the terminals TC and TD. The direct current power DC output from each antenna element group circuit 96 is combined, and the combined direct current power DC is supplied to the load 30 via the switch unit 21 .

[0141] Furthermore, when the DC power output from the antenna element is equal to or greater than a threshold value Tb (where Ta > Tb) (in the case of medium input power), the antenna element group circuit 96 selects one antenna element and outputs the output of the selected antenna element to the second rectifier circuit. For example, the antenna element group circuit 96 performs switching control on the switch unit 98A so that an RF signal from the antenna element 97A is supplied to terminals TA and TB. The antenna element group circuit 96 also performs switching control on the switch units 98B, 98C, and 98D so that RF signals from the antenna elements 97B, 97C, and 97D are not output. In response to this control, the RF signals output from the respective antenna element group circuits 96 are combined and supplied to the rectifier circuit 20. That is, the RF signals from the four antenna elements are combined and supplied to the rectifier circuit 20. In this case, the number of antenna elements connected to the rectifier circuit 20 is four. The combined RF signal is rectified by the rectifier circuit 20 to obtain DC power, which is then supplied to the load 30 via the switch unit 21 .

[0142] Furthermore, when the input power is low and the DC power output from the antenna elements is less than the threshold value Tb, the antenna element group circuit 96 selects all antenna elements and outputs the outputs of the selected antenna elements to the corresponding second rectifier circuits. For example, the antenna element group circuit 96 controls the switching of the switch units 98A, 98B, 98C, and 98D so that the RF signals output from the antenna elements 97A, 97B, 97C, and 97D are supplied to the terminals TA and TB, respectively. In response to this control, an RF signal obtained by combining the RF signals from the four antenna elements is output from the terminals TA and TB. The RF signals output from the four antenna element group circuits 96 are then combined and supplied to the rectifier circuit 20. That is, the RF signals output from 16 antenna elements are combined and supplied to the rectifier circuit 20. In this case, the number of antenna elements connected to the rectifier circuit 20 is "16." The combined RF signal is rectified by the rectifier circuit 20 to obtain DC power, which is then supplied to the load 30 via the switch unit 21. The number of thresholds set for the output parameters may be three or more instead of two. This modification also provides the same effects as those described in the eighth embodiment.

[0143] Also, as shown in FIG. 29 , a switch section 110A may be connected to terminals TA and TB of the antenna element group circuit 96A, a switch section 110B may be connected to terminals TA and TB of the antenna element group circuit 96B, a switch section 110C may be connected to terminals TA and TB of the antenna element group circuit 96C, and a switch section 110D may be connected to terminals TA and TB of the antenna element group circuit 96D.

[0144] A rectifier circuit 120A and a rectifier circuit 20 are connected to the output stage of the switch unit 110A. The switch unit 110A switches the supply destination of the RF signals output from the terminals TA and TB of the antenna element group circuit 96A between the rectifier circuit 120A and the rectifier circuit 20. A rectifier circuit 120B and a rectifier circuit 20 are connected to the output stage of the switch unit 110B. The switch unit 110B switches the supply destination of the RF signals output from the terminals TA and TB of the antenna element group circuit 96B between the rectifier circuit 120B and the rectifier circuit 20. A rectifier circuit 120C and a rectifier circuit 20 are connected to the output stage of the switch unit 110C. The switch unit 110C switches the supply destination of the RF signals output from the terminals TA and TB of the antenna element group circuit 96C between the rectifier circuit 120C and the rectifier circuit 20. The rectifier circuit 120D and the rectifier circuit 20 are connected to the output stage of the switch unit 110D. The switch unit 110D switches the supply destination of the RF signals output from the terminals TA and TB of the antenna element group circuit 96D to the rectifier circuit 120D or the rectifier circuit 20. The outputs of the rectifier circuits 120A, 120B, 120C, and 120D can be combined and supplied to the load 30 via the switch unit 21, for example.

[0145] 29 , rectifier circuits (in this example, rectifier circuit 120A, rectifier circuit 120B, rectifier circuit 120C, and rectifier circuit 120D) can be provided for RF signals output from and combined with the four antenna elements included in each antenna element group circuit. The DC power output from each of the four rectifier circuits, rectifier circuit 120A, rectifier circuit 120B, rectifier circuit 120C, and rectifier circuit 120D, may be combined and supplied to switch unit 21. Furthermore, in accordance with switching control of switch unit 110A, etc., DC power output from any of the four rectifier circuits may be supplied to switch unit 21, or DC power output from some, but not all, of the four rectifier circuits (e.g., rectifier circuit 120A and rectifier circuit 120B) may be supplied to switch unit 21.

[0146] In the above-described embodiment, an example was described in which switching control for each switch unit was performed automatically, but the switches may also be manually operated. This allows the rectenna device to operate in the manner desired by the user, making it possible to provide a rectenna device (electronic device having a rectenna device) that can accommodate customization needs.

[0147] If the electronic device is an autonomously mobile robot, and the output parameter (e.g., voltage) detected by the output parameter detection unit 41 is small, the electronic device may be moved closer to the power transmitter so that the input power to the antenna element of the rectenna device is increased.

[0148] Multiple electronic devices may have rectenna devices, and these electronic devices may communicate with each other to switch the switch unit, thereby switching the wiring. This configuration allows for high conversion efficiency of electromagnetic waves from a power transmitter in multiple power receiver electronic devices. For example, among multiple power receiver electronic devices (devices), one electronic device acts as a host and manages the other electronic devices. Then, for example, only the host electronic device detects output parameters and performs switching control based on the output parameters. The host electronic device transmits control information for performing switching control based on the output parameters to the other electronic devices via communication. The other electronic devices perform switching control of each switch unit based on the control information transmitted from the host electronic device. This allows multiple power receiver electronic devices to perform the same switching control. Since only the host electronic device needs to have the output detection function, the electronic device can be configured to maintain high conversion efficiency while being simple and low-cost, and can be an electronic device that is not dependent on the specifications of the power transmitter.

[0149] Furthermore, the multiple technologies related to the present technology can be implemented independently and independently, as long as no contradiction occurs. Of course, any multiple technologies can also be implemented in combination. For example, part or all of the present technology described in any embodiment can be implemented in combination with part or all of the present technology described in another embodiment. Furthermore, part or all of any of the above-mentioned technologies can be implemented in combination with other technologies not described above.

[0150] Furthermore, the configurations, methods, steps, shapes, materials, and numerical values, etc., described in the embodiments and modifications are merely examples, and different configurations, methods, steps, shapes, materials, and numerical values, etc., may be used as needed. Furthermore, the materials exemplified in the embodiments and modifications may be used alone or in combination of two or more types, unless otherwise specified. Furthermore, the components described in the embodiments and modifications may be combined as appropriate.

[0151] The effects described in this specification are merely examples and are not limiting, and other effects may also be present.

[0152] The present technology may also adopt the following configurations. (1) A rectenna device comprising: two or more antenna elements; a first rectifier circuit provided for each of the antenna elements and rectifying the output of the antenna elements; and a second rectifier circuit that allows the outputs of the two or more antenna elements to be combined and input and rectifies the combined output, wherein control is performed to change the number of the antenna elements connected to each of the first rectifier circuit and the second rectifier circuit. (2) The rectenna device described in (1), wherein control is performed to change the number of the antenna elements in accordance with an output parameter corresponding to input power to the antenna elements. (3) The rectenna device described in (2), wherein the output parameter includes at least one of an output voltage of the rectifier circuit, an output current of the rectifier circuit, an output power of the rectifier circuit, an impedance of the rectifier circuit, and a parameter related to a load connected to the rectenna device. (4) The rectenna device according to (2), wherein, when the output parameter is a first output parameter corresponding to input power to the antenna elements being smaller than a predetermined value, control is performed to reduce the number of antenna elements connected to the first rectifier circuit and increase the number of antenna elements connected to the second rectifier circuit, and when the output parameter is a second output parameter corresponding to input power to the antenna elements being larger than a predetermined value, control is performed to increase the number of antenna elements connected to the first rectifier circuit and decrease the number of antenna elements connected to the second rectifier circuit. (5) The rectenna device according to (4), wherein a first output obtained by combining outputs of two or more of the first rectifier circuits and a second output from the second rectifier circuit are switched and output. (6) The rectenna device according to (5), wherein the connection topology of the antenna elements is changeable. (7) The rectenna device according to (5) or (6), wherein a converter is included that boosts the second output. (8) The rectenna device according to any one of (5) to (7), further comprising a converter that reduces the voltage of the first output. (9) The rectenna device according to any one of (1) to (8), further comprising a first rectifier circuit and a second rectifier circuit that have a common configuration.(10) The rectenna device according to any one of (1) to (9), wherein a matching circuit is provided at an input stage of the second rectifier circuit. (11) The rectenna device according to any one of (1) to (10), wherein the first rectifier circuit is provided for each antenna element group consisting of a plurality of the antenna elements. (12) The rectenna device according to any one of (2) to (8), wherein the first rectifier circuit is provided for each antenna element group consisting of a plurality of the antenna elements, and wherein the number of the antenna elements connected to the second rectifier circuit is changed according to a plurality of threshold values ​​set for the output parameter. (13) The rectenna device according to any one of (1) to (12), wherein the phase difference between the output of the antenna element and the input to the second rectifier circuit is an integer multiple of approximately 360 degrees. (14) The rectenna device according to (13), wherein the transmission line length between the antenna element and the second rectifier circuit is set so that the phase difference between the output of the antenna element and the input to the second rectifier circuit is an integer multiple of approximately 360 degrees. (15) The rectenna device according to (13), wherein a phase shifter is provided between the antenna element and the second rectifier circuit so that the phase difference between the output of the antenna element and the input to the second rectifier circuit is an integer multiple of approximately 360 degrees. (16) The rectenna device according to (1), comprising a communication unit that communicates with a power transmitter, and wherein control is performed to change the number of antenna elements connected to the first rectifier circuit and the second rectifier circuit depending on the content of communication by the communication unit. (17) The rectenna device according to any of (1) to (16), comprising a substrate on which the rectenna device is mounted. (18) The rectenna device according to (17), wherein a block having at least the antenna elements, the first rectifier circuits provided for each of the antenna elements, and a switch unit that switches between the output of the antenna elements and the output from the first rectifier circuits is detachable from the substrate. (19) The rectenna device according to (17), wherein the block having the antenna elements is detachable from the substrate. (20) An electronic device comprising: the rectenna device according to any of (1) to (19); and a load connected to the rectenna device.

[0153] DESCRIPTION OF SYMBOLS 100A to 100J... Rectenna device 10A, 10B, 10C, 10D... Antenna elements 11A, 11B, 11C, 11D... Switch unit 12A, 12B, 12C, 12D... Rectifier circuit (first rectifier circuit) 20... Rectifier circuit (second rectifier circuit) 21... Switch unit 30... Load 40... Control unit 41... Output parameter detection unit 55... Matching circuit 56A, 56B, 56C, 56D... Phase shifter 64A, 64B, 64C, 64D... Antenna element group 72A, 72B... Block 86... DC-DC converter 300A, 300B... Electronic device 302... Communication module

Claims

1. A rectenna device comprising: two or more antenna elements; a first rectifier circuit provided for each of the antenna elements and rectifying the output of the antenna elements; and a second rectifier circuit that allows the outputs of the two or more antenna elements to be combined and input and rectifies the combined output, wherein control is performed to change the number of antenna elements connected to each of the first rectifier circuit and the second rectifier circuit.

2. The rectenna device according to claim 1, wherein the number of antenna elements is changed in accordance with an output parameter corresponding to an input power to the antenna elements.

3. The rectenna device according to claim 2, wherein the output parameters include at least one of an output voltage of the rectifier circuit, an output current of the rectifier circuit, an output power of the rectifier circuit, an impedance of the rectifier circuit, and a parameter related to a load connected to the rectenna device.

4. A rectenna device as described in claim 2, wherein, when the output parameter is a first output parameter corresponding to the input power to the antenna elements being smaller than a predetermined value, control is performed to reduce the number of antenna elements connected to the first rectifier circuit and to increase the number of antenna elements connected to the second rectifier circuit, and when the output parameter is a second output parameter corresponding to the input power to the antenna elements being greater than a predetermined value, control is performed to increase the number of antenna elements connected to the first rectifier circuit and to reduce the number of antenna elements connected to the second rectifier circuit.

5. A rectenna device as described in claim 4, wherein a first output obtained by combining the outputs of two or more of the first rectifier circuits and a second output from the second rectifier circuit are switched and output.

6. The rectenna device according to claim 5, wherein the connection configuration of the antenna elements is changeable.

7. A rectenna device as described in claim 5, further comprising a converter for boosting the second output.

8. A rectenna device as described in claim 5, further comprising a converter for stepping down the first output.

9. The rectenna device according to claim 1, wherein the first rectifier circuit and the second rectifier circuit have a common configuration.

10. A rectenna device as described in claim 1, wherein a matching circuit is provided at an input stage of the second rectifier circuit.

11. The rectenna device according to claim 1, wherein the first rectifier circuit is provided for each antenna element group consisting of a plurality of the antenna elements.

12. A rectenna device as described in claim 2, wherein the first rectifier circuit is provided for each antenna element group consisting of a plurality of the antenna elements, and the number of the antenna elements connected to the second rectifier circuit is changed according to a plurality of threshold values ​​set for the output parameter.

13. The rectenna device according to claim 1, wherein a switch section is provided for each of the antenna elements, which switches between connection to the first rectifier circuit and connection to the second rectifier circuit.

14. The rectenna device according to claim 1, wherein the phase difference between the output of the antenna element and the input to the second rectifier circuit is an integer multiple of approximately 360 degrees.

15. A rectenna device as described in claim 13, wherein the length of the transmission line between the antenna element and the second rectifier circuit is set so that the phase difference between the output of the antenna element and the input to the second rectifier circuit is an integer multiple of approximately 360 degrees.

16. A rectenna device as described in claim 1, further comprising a communication unit that communicates with a power transmitter, and wherein control is performed to change the number of antenna elements connected to the first rectifier circuit and the second rectifier circuit depending on the content of communication by the communication unit.

17. A rectenna device as described in claim 1, comprising a substrate on which the rectenna device is mounted.

18. A rectenna device as described in claim 17, wherein a block having at least the antenna element, the first rectifier circuit provided for each antenna element, and a switch section for switching between the output of the antenna element and the output from the first rectifier circuit is detachably attached to the substrate.

19. The rectenna device according to claim 17, wherein a block having the antenna elements is detachable from the substrate.

20. An electronic device comprising: a rectenna device according to claim 1; and a load connected to the rectenna device.

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