Receiving device and power supply device

Abstract

To use an industrial product metal portion as an antenna to receive electric field energy of a radio wave or a quasi-electrostatic field (near field) in a space and convert it into energy.SOLUTION: An antenna device includes an antenna unit including: a rectifier circuit that receives electric field energy of a radio wave or a quasi-electrostatic field (near field) in a space and rectifies an AC signal into a direct current; a first antenna element that is a conductor to be in contact with or connected to an industrial product metal portion; and a second antenna element that is a conductor different from the first antenna element and provided not to be electrically connected to the industrial product metal portion. An input line output from the first antenna element to a rectifier circuit unit of the AC signal output from the antenna unit is connected to the rectifier circuit.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present technology relates to an antenna device, a rectifier circuit, and an electronic device that have an energy harvesting function. [Background technology]

[0002] Energy harvesting is being considered, which involves converting the energy of radio waves, such as broadcast waves, that exist around us into electricity. In the case of energy harvesting, the current that flows through the circuit via the antenna is rectified to direct current and converted into electrical energy. A diode is used to rectify radio waves to direct current. An antenna with a rectifier circuit is called a rectenna.

[0003] Non-Patent Document 1 describes that a high-impedance antenna is used to receive terrestrial digital broadcasting in the 470 to 600 MHz band, and the efficiency of the rectenna is increased by increasing the excitation voltage of the rectifier.

[0004] Non-patent document 2 describes the measurement results of the power flux density of V-High multimedia broadcasting (208.5-222 MHz), terrestrial digital broadcasting (470-710 MHz), and 800 MHz band mobile phone base stations (860-890 MHz), as well as an evaluation of antennas for electromagnetic wave recovery. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] "Design and Received Power Level of a High-Impedance, Wideband Folded Dipole Antenna for Energy Harvesting," Kei Miyakoshi, Keisuke Noguchi, Kenji Ito, Jiro Ida, IEICE Technical Report Vol.114, No.245, pp.13-18 [Non-patent document 2] "Invited Lecture: Electromagnetic Energy Recovery from Three Frequency Bands Used for Broadcasting and Communications," Shoichi Kitazawa, Hirokazu Kamoda, Hiroshi Ban, Naoya Kukutsu, and Kiyoshi Kobayashi, IEICE Technical Report WPT2013-26 (2013-11) Summary of the Invention [Problem to be solved by the invention]

[0006] Both of the above-mentioned Non-Patent Documents 1 and 2 only target the electromagnetic energy of radio waves propagating through the air, and are configured to design an antenna tuned to the frequency and include a matching section for impedance matching. Such configurations have the problem of only being able to receive signals at the matched frequency, resulting in significantly reduced power. In particular, a separate antenna is required to match the frequency to be received. To receive broadcast waves, the antenna must be approximately half the size of the wavelength. Smaller antennas result in reduced reception efficiency, significantly limiting the range of application. In other words, to receive power over a wide frequency range, multiple antennas sized to match the frequencies to be received are required, and these antennas must be installed separately.

[0007] Therefore, the object of this technology is to provide an antenna device, a rectifier circuit, and an electronic device that can obtain greater received power by incorporating electric field energy of a quasi-electrostatic field (near field) in addition to radio waves that exist over a wide range, in a configuration different from that of conventional receiving antennas that convert radio wave energy into electric power. [Means for solving the problem]

[0008] This technology is an antenna device that has an antenna unit equipped with a rectifier circuit for receiving radio waves in space or electric field energy of a quasi-electrostatic field (near field) and rectifying the AC signal to DC, and that is composed of a first antenna element that is a conductor that contacts or is connected to the metal part of an industrial product, and a second antenna element that is a conductor separate from the first antenna element and is arranged so as not to be electrically connected to the metal part of the industrial product, and the input line of the AC signal output from the antenna unit that is output from the first antenna element to the rectifier circuit unit is connected to the rectifier circuit. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a block diagram of an embodiment of a receiving device according to the present technology. [Figure 2] 2A, 2B, and 2C are a plan view and a cross-sectional view of an example of an antenna device included in a receiving device. [Figure 3] 3A and 3B are a plan view and a cross-sectional view of another example of an antenna device included in a receiving device. [Figure 4] FIG. 4 is a schematic diagram for explaining a specific example of an antenna device. [Figure 5] FIG. 5 is a schematic diagram illustrating a first example of an antenna device including a device substrate. [Figure 6] FIG. 6 is a schematic diagram for explaining a modified example of the first example. [Figure 7] FIG. 7 is a schematic diagram illustrating a second example of an antenna device including a device substrate. [Figure 8] FIG. 8 is a schematic diagram for explaining a modified example of the second example. [Figure 9] FIG. 9 is a schematic diagram illustrating a third example of an antenna device including a device substrate. [Figure 10] FIG. 10 is a connection diagram for explaining a modified example of the antenna device. [Figure 11] FIG. 11 is a connection diagram for explaining a modified example of the antenna device. [Figure 12]12A, 12B, and 12C are schematic diagrams each showing a specific example of the second antenna element. [Figure 13] FIG. 13 is a schematic diagram for explaining the operation of the antenna device. [Figure 14] FIG. 14 is a schematic diagram used to explain an embodiment in which the present technology is applied to a metal rack. [Figure 15] FIG. 15 is a schematic diagram used to explain an example of an embodiment. [Figure 16] FIG. 16 is a schematic diagram used to explain a modified example of an embodiment. [Figure 17] 17A and 17B are schematic diagrams used to explain an embodiment in which the invention is applied to a microwave oven. [Figure 18] FIG. 18 is a connection diagram showing a configuration of an example of a rectifier circuit. [Figure 19] FIG. 19 is a connection diagram showing the configuration of another example of the rectifier circuit. [Figure 20] FIG. 20 is a graph illustrating the characteristics of the diodes in the rectifier circuit. [Figure 21] FIG. 21 is a block diagram of a modified circuit configuration. [Figure 22] FIG. 22 is a connection diagram showing an example of the configuration of an antenna device using another example of a rectifier circuit. [Figure 23] FIG. 23 is a connection diagram showing another example of the configuration of an antenna device using another example of a rectifier circuit. [Figure 24] FIG. 24 is a connection diagram showing yet another example of the configuration of the antenna device using another example of the rectifier circuit. [Figure 25] FIG. 25 is a connection diagram used to explain an application example of the antenna device. [Figure 26] FIG. 26 is a graph used to explain an application example of the antenna device. [Figure 27] 27A and 27B are schematic diagrams used to explain another embodiment in which the present technology is applied to a car. [Figure 28] FIG. 28 is an enlarged perspective view of a partial cross section of the tire. [Figure 29] FIG. 29 is a block diagram showing a configuration of another application example of the present technology. [Figure 30] 30A and 30B are block diagrams showing a general configuration for increasing output. [Figure 31] FIG. 31 is a block diagram of an example of a configuration in which antenna devices are connected in series. [Figure 32] FIG. 32 is a connection diagram showing an example of the circuit connection of FIG. [Figure 33] FIG. 33 is a block diagram of another example of a configuration in which antenna devices are connected in series. [Figure 34] FIG. 34 is a connection diagram showing an example of the circuit connection of FIG. [Figure 35] FIG. 35 is a block diagram of an example of a configuration in which antenna devices are connected in parallel. [Figure 36] FIG. 36 is a connection diagram showing an example of the circuit connection of FIG. [Figure 37] FIG. 37 is a block diagram of another example of a configuration in which antenna devices are connected in parallel. [Figure 38] FIG. 38 is a connection diagram showing an example of the circuit connection of FIG. [Figure 39] FIG. 39 is a schematic diagram used to explain the case where the number of antennas is increased. [Figure 40] 40A and 40B are connection diagrams used to explain the case where the number of antennas is increased. DETAILED DESCRIPTION OF THE INVENTION

[0010] The embodiments described below are preferred specific examples of the present technology, and various technically preferable limitations are applied. However, the scope of the present technology is not limited to these embodiments unless otherwise specified in the following description to the effect that the present technology is limited. Furthermore, in the following description, the same names and symbols indicate the same or similar components, and redundant descriptions will be omitted as appropriate.

[0011] This technology allows metal parts (iron, aluminum, copper, metal alloys, etc.) in everyday industrial products, such as cars, vending machines, refrigerators, microwave ovens, metal racks, guardrails, mailboxes, traffic lights, etc., that have metal parts that induce electric field energy to act as antennas and receive the electric field energy of radio waves and quasi-electrostatic fields (near fields) in space. In other words, if there is metal floating in space, various types of AC power (alternating current) will flow on the metal surface, so this metal can be considered an antenna and this power can be efficiently converted into energy.

[0012] For example, electric field energy is induced in the metal parts (iron, aluminum, copper, metal alloys, etc.) of industrial products that are found all around us, such as cars, vending machines, refrigerators, microwave ovens, metal racks, guardrails, mailboxes, and traffic lights. This technology uses such metal parts of industrial products as antennas to receive the electric field energy of radio waves and quasi-electrostatic fields (near-field) in space. In other words, if a metal exists floating in space, various types of alternating current (AC) power (alternating current) flow on its surface. This technology treats the metal as an antenna and efficiently converts this power into energy. Note that metal parts of industrial products are metal parts other than industrial products that are designed as antennas.

[0013] The input terminal, which is in contact with or connected to the metal part of an industrial product and turns the metal part itself into an antenna, should have a high receiving impedance when connected to the subsequent rectifier circuit, and so is connected in series without a matching circuit specifically tailored to the frequency, and rectified with a diode with a very small reverse current relative to the forward current.This makes it possible to efficiently receive not only conventional radio waves, but also quasi-electrostatic field (near field) power, which is not radio waves such as 50 / 60 Hz that leak from very small power sources.

[0014] In this way, the antenna shape does not need to be considered between the input terminal connected to the metal part of the industrial product and the rectifier circuit, eliminating the need for a matching circuit. As a result, the first method allows the ground of the antenna device to be capacitively coupled to the ground or to be grounded via a cable, creating an electric field. This makes it possible to capture electric field energy in quasi-electrostatic fields other than radio waves. The second method allows a separate antenna element, separate from the ground of the antenna device, to be capacitively coupled to the ground or to be grounded via a cable, creating an electric field. This makes it possible to capture electric field energy in quasi-electrostatic fields other than radio waves. This technology makes it possible to receive and convert power and noise leaking from power cords and inverters into energy. This technology can receive a wide range of electric field energy, thereby increasing received power. A quasi-electrostatic field is a voltage phenomenon that does not propagate like a radiated electromagnetic field (i.e., radio waves) but is distributed around people, vehicles, and objects like electrostatic charges. While electrostatic fields are considered to have zero time variation, quasi-electrostatic fields have frequency components and vary with time.

[0015] 1 shows an embodiment of an antenna device with an energy harvesting function according to the present technology. Electric field energy is received by an antenna unit 1a consisting of a first antenna element and a second antenna element, and the output of the antenna unit 1a is supplied to a rectifier circuit 2. The antenna unit 1a and the rectifier circuit 2 constitute the antenna device 1.

[0016] The output of the rectifier circuit 2 is supplied to a charger 3. A storage element 4 is connected to the charger 3. The storage element 4 is charged by the charger 3. The charger 3 may be configured to control the discharge of the storage element 4. The antenna device 1, the charger 3, and the storage element 4 form a receiving device. A load 5 is connected to the storage element 4. The load 5 operates using the power stored in the storage element 4. The load 5 may be a microcomputer, a wireless communication unit, a sensor, or the like. The output of the sensor is wirelessly transmitted under the control of the microcomputer.

[0017] The antenna device 1 is composed of a first antenna element and a second antenna element that are in contact with a metal. An example of the antenna device 1 will be described with reference to FIGS. 2A (plan view), 2B (cross-sectional view), 2C (cross-sectional view), 3A (plan view), and 3B (cross-sectional view), as well as diagrams of a board (FIGS. 5 and 6) on which a rectifier circuit 2 (described later) is mounted. As shown in FIGS. 2A, 2B, 2C, 3A, and 3B, a first antenna element 11 that comes into contact with or is connected to a metal part of an industrial product is configured in a plate (patch) shape. The antenna element 11 is a plate made of a conductor such as gold, silver, aluminum, copper, iron, nickel, or an alloy. The surface of the antenna element 11 that comes into contact with the metal may be resin-coated. The antenna element 11 is shaped like a line, pin, hemisphere, or has an uneven shape, depending on the shape of the metal part of the industrial product. The metal part of the industrial product and the antenna element 11 come into contact with or are connected to each other by welding, mechanical bonding (such as caulking), bonding with a conductive adhesive, or attaching to iron material or the like using magnetism such as a magnet. Furthermore, conductive resin or conductive rubber containing, for example, carbon or metal may be used as the antenna element 11. By using conductive resin, for example, electrodes of various shapes can be easily formed. Furthermore, by using conductive rubber, it is possible to form electrodes that are elastically deformable or electrodes with high adhesion. Additionally, the material of the antenna element 11 is not limited, and the above-mentioned materials may be used alone, or the electrodes may be formed by combining the materials.

[0018] It is acceptable for the antenna element 11 to be capacitively coupled to metal even if space or an insulator is interposed between them. Figure 4 shows a desk light 6 equipped with a fluorescent lamp 7. The antenna device 1 is attached to a main body 8 and is housed in, for example, a resin case.

[0019] Circuitry such as an inverter is mounted on a circuit board 9 housed within a resin case in the main body 8. The inverter converts 50 Hz or 60 Hz commercial power into direct current, which is then converted into a high-frequency signal of 20 to 50 kHz to light the fluorescent lamp 7. This lighting method eliminates the flickering characteristic of fluorescent lamps compared to lighting using commercial power frequencies. Spatial noise is generated from the circuit board, as indicated by the arrows. The antenna device 1 is spatially coupled to the board on which the inverter and other circuitry are mounted, and can induce voltage due to the spatial noise. For example, experiments have confirmed that a voltage of approximately 4.4 V is induced when the fluorescent lamp is turned on.

[0020] 2B and 2C, for example, a plate-shaped (patch-shaped) antenna element 11 and an equipment substrate (circuit board) 12 are arranged opposite each other, and a dielectric plate 13 is interposed between the antenna element 11 and the equipment substrate 12. It is also possible to leave a space between the antenna element 11 and the equipment substrate 12 without providing the dielectric plate 13.

[0021] To electrically connect the antenna element 11 and the device board 12, one end of the antenna element 11 and the conductive pin 14 are electrically connected, and the other end of the conductive pin 14 penetrates the device board 12 and is soldered to a signal path electrode on the back surface of the device board 12. The antenna section 1a is composed of the antenna element 11 and a ground formed by the copper foil pattern on the device board 12. The ground serves as a second antenna element. The antenna section 1a has a T-shaped antenna structure with a flat plate as the antenna element. The connection portion between the signal path electrode on the device board 12 and the conductive pin 14 serves as the antenna feed point 15. A circuit section 16 is provided on, for example, the back surface of the device board 12.

[0022] The antenna device having the above-described configuration is housed in a case 17. The contact surfaces of the case 17 other than the antenna element 11 are made of an insulating material such as resin. In addition, the side surfaces and the opposite surface of the case other than the contact surfaces with the metal from which energy is intended to be taken in are also made of an insulating material.

[0023] 2C shows a configuration in which case 17 is made up of case 17A, which is made of a non-metallic material such as resin, and case 17B, which is made of a metal. It is also possible to configure case 17B so that ground 19 on either the top or bottom surface of device board 12 is electrically connected to case 17B. That is, case 17A, which is made of an insulating material and on which antenna element 11 is provided, and case 17B, which is made of a metallic material and forms the opposite surface, may be connected by connecting part 22 such as a screw, and case 17B may be connected to ground 19 of device board 12 by wire 23.

[0024] 3A and 3B, an insulated sheathed cable 24 may be connected by soldering or the like to the ground 19 formed by the copper foil pattern on the device substrate 12, so as to be grounded to the earth ground. In this embodiment, the antenna element 11 is formed in a plate shape and is configured to be in contact with or connected to the metal part of the industrial product, but the connection between the antenna element 11 and the feeding point 15 can also be configured by directly connecting to the metal part of the industrial product using an insulated sheathed cable or the like.

[0025] As shown in Fig. 5, a ground 19 formed of a copper foil pattern is formed on the circuit board 12, and the antenna element 11 and the ground 19 formed of the copper foil pattern on the device board 12 constitute the antenna section 1a. The ground 19 is a second antenna element. Furthermore, an electrostatic protection component, such as a varistor 18, is inserted between the antenna element 11, which is in contact with or connected to metal, and the ground formed of the copper foil pattern of the receiving device as a countermeasure against static electricity. The varistor 18 may be connected between the output terminal 34a and the ground 19.

[0026] The circuit section 16 includes a rectifier circuit 2. The rectifier circuit 2 is arranged so as not to overlap with the ground 19 formed by the copper foil pattern of the device substrate 12. An input line output from the antenna element 11 to the rectifier circuit 2 is connected in series to the rectifier circuit without passing through a matching circuit. The charger 3 and the storage element 4 (not shown) may be included in the circuit section 16, or may be present separately.

[0027] 6 shows the configuration of the device board 12 corresponding to FIGS. 3A and 3B. The ground 19 (shown as a shaded area) formed by the copper foil pattern of the device board 12 is grounded to the earth ground via an insulated sheathed cable 24. The earth ground may also be something that functions as a low-potential ground, such as a wide conductive plate, including the earth. The varistor 18 may be connected between the output terminal 34a and the ground 19.

[0028] Next, as shown in FIG. 7, a separate second antenna element 20 (shown as a shaded area) formed of a copper foil pattern may be configured on the above-mentioned substrate. In this case, the separate second antenna element 20 must not come into contact with or be connected to the metal part of the industrial product from which energy is intended to be captured. Also, as shown in FIG. 8, an insulated sheathed cable 25a may be further connected to the ground 19 (shown as a shaded area) formed of a copper foil pattern on the equipment substrate 12, thereby grounding it to the ground. Although FIGS. 7 and 8 show the antenna element 11 formed on a separate substrate, it may also be formed on a metal part, such as a housing, that is configured to not come into contact with metal, opposite the metal contact surface of the receiver. In this case, an electrostatic protection component, such as a varistor 21, may be inserted between the antenna element 11, which comes into contact with metal, and the ground of the receiving equipment as a countermeasure against static electricity. The varistor 21 may also be connected between the output terminal 34a and the ground 19.

[0029] Furthermore, as shown in Figure 9, an electrostatic protection component, such as a varistor 21, may be inserted between the antenna element 11 and the antenna element 20 as a countermeasure against static electricity, and an insulated cable 25b may be connected to the antenna element 20 and grounded to the earth. In this case, the antenna element 20 can extract much more power than the electric field generated by capacitive coupling with the earth ground. When extracting power from metal products such as microwave ovens and refrigerators in a room, it is necessary to connect the power to the ground as a countermeasure against static electricity. When extracting power from the metal parts of such products, it is necessary to connect the power to the ground using an insulated cable, as described above. The varistor 21 may also be connected between the output terminal 34a and the ground 19.

[0030] Figures 10 and 11 show modified examples of Figures 5 and 7. That is, when an industrial product has a metal part that is directly earthed to the ground with an insulated wire, the wire is grounded via an electrostatic protection component such as a varistor 18. The above-mentioned configuration is used for existing electrical products that require a separate earth connection.

[0031] Other configurations of the second antenna element 20 are shown in Fig. 12. Fig. 12A shows a meander line 20a configuration, and Fig. 12B shows a coil 20b configuration. The coil 20b may be a chip coil configuration. Fig. 12C shows a configuration having an inductor 20c at the tip. These configurations can reduce the occupied area, increase the antenna length, and increase the induced voltage.

[0032] There is a great deal of electric field energy all around us, which can be divided into low-frequency and high-frequency components. For example, the leakage electric field (50Hz / 60Hz) from a household AC power supply and noise present near a personal computer are low-frequency components. These are called quasi-electrostatic fields (near fields). On the other hand, radio broadcasts (AM / FM), television broadcasts, and mobile phone radio waves are high-frequency components. These are called radio waves (far fields).

[0033] 13, the antenna element 11 of the above-described antenna device 1 is brought into contact with a metal part of an industrial product, for example, the metal of a metal rack 91. The antenna element 11 is attached to one surface of the metal rack 91. Electrically, the metal part and the antenna element 11 are in contact with each other through capacitive coupling. By using the metal part of the metal rack 91 as an antenna, the antenna device 1 can capture the energy of both low-frequency quasi-electrostatic fields such as noise and radio waves such as broadcast waves.

[0034] In the antenna device 1, it is preferable for the antenna element 11 to be directly connected to the metal part of the industrial product, but in this example, it is basically in surface contact to increase capacitance. As long as it is in contact with the metal part, the contact may be flat, or may be a pin structure, a hemispherical structure, or a concave-convex fitting structure. The connection may be by screwing, soldering, welding, or the like, directly, or via an insulator such as an insulating cable or conductive rubber (or air). The antenna unit 1a, which is composed of the antenna element 11 in contact with the metal and the ground electrode 19 of the device substrate 12 or a separate second antenna element 20, can receive electric field energy and generate power.

[0035] As shown in Figure 14, for example, a metal rack 91 exists in an electrically floating state on an insulating carpet, and when an antenna device 1 (shaded area) including an antenna unit 1a is attached to the metal rack 91, the circuit configurations shown in Figures 5 and 7 can be adopted. In this case, the ground 19 (not shown) of the equipment board 12 or the separate second antenna element 20 (not shown) can be capacitively coupled to the ground (GND1) to form a large antenna unit. This antenna unit can receive low-frequency quasi-electrostatic fields.

[0036] When the circuit configuration shown in Figure 15 is as shown in Figure 10, the effect of taking in energy from space is further enhanced. In other words, this can be achieved by connecting the separate second antenna element 20 to the ground (GND) of a grounded outlet, for example, via an insulating cable 25c.

[0037] Furthermore, as shown in FIG. 16, the antenna device 1 (shaded portion) including the antenna portion 1a may be connected to a metal plate 93 by an insulating cable 92, and the metal plate 93 may be brought close to the ground (GND1), so that the antenna device is capacitively coupled to the ground (GND1).

[0038] Next, configuration examples of the embodiments of Figures 10 and 11 are shown in Figures 17A and 17B. When earth cable 82 attached to microwave oven 81 is grounded, electrostatic protection component 83 is provided between the cable and the earth terminal of the power outlet. Electrostatic protection component 83 has a screw portion 85 for connecting earth cable 82, a varistor 84 for electrostatic protection, and other components provided on a board, and earth cable 82 is soldered onto the board.

[0039] In this way, the antenna device 1 is capable of receiving electric field energy over a wide frequency range. Therefore, the antenna device according to the present technology can easily capture a wide range of electric field energy simply by contacting metal. Furthermore, if a larger amount of energy is desired to be captured, connection by soldering or the like to the metal part of the industrial product is preferable. Also, if the metal rack is made of iron, a magnet may be used to maintain the connection.

[0040] An example of the rectifier circuit 2 is shown in Figure 18. While a typical rectifier circuit can rectify low voltages, such as those used in energy harvesting, a certain level of voltage is required to quickly store energy. Therefore, a voltage boost, like a voltage doubler circuit, is required. Therefore, by inserting a capacitor with the desired voltage level before the diode and rectifying it, the voltage corresponding to the capacitor is added, enabling boosting. Therefore, a full-wave quadruple voltage rectifier circuit is configured, consisting of input capacitors 26 and 27 connected to the antenna section 1a, diodes 28, 29, 30, and 31, and capacitors 32 and 33. DC is output from both ends of the series connection of capacitors 32 and 33 to output terminals 34a and 34b. In this configuration, capacitors 32 and 33 not only boost the voltage but also actually store the current. Therefore, a large capacitance and low leakage current are recommended for these components.

[0041] This example is a full-wave 4x voltage rectifier circuit, but it can also be a rectifier circuit incorporating a normal 1x half-wave rectifier circuit, a full-wave rectifier circuit, a voltage doubler rectifier circuit, or a Cockcroft-Walton circuit. Also, in terms of efficiency, a full-wave rectifier circuit can increase the voltage of the AC signal and take in all of it, so for the diodes used for rectification this time, the full-wave rectifier circuit gave better results, even including diode loss. This is a two-stage 4x voltage full-wave rectifier, but if you want to increase the extracted voltage, you can add more stages.

[0042] An example of the values ​​of each element is shown below: Capacitors 26, 27: 0.22 μF, 32, 33: 47 μF Diodes 28, 29, 30, 31: 1N60 (silicon)

[0043] In the case of the above-mentioned quadruple voltage rectifier circuit, it is important that the leakage current of the diodes under reverse bias is very small. If leakage current is present, a full-wave rectifier circuit is suitable. Another example of the rectifier circuit 2 (full-wave rectifier circuit) is shown in FIG. 19. As shown in FIG. 19, diodes 61 and 64 are connected in series, and diodes 63 and 62 are connected in series. The junction of the anode of diode 61 and the cathode of diode 64 is connected to the first antenna element 11, and the junction of the anode of diode 63 and the cathode of diode 62 is connected to the second antenna element 20. The junction of the cathode of diode 61 and the cathode of diode 63 is connected to one output terminal 34a via a reverse current prevention diode 65, and the junction of the anode of diode 64 and the anode of diode 62 is connected to the other output terminal 34b. An electrostatic discharge (ESD) varistor 66 and an IC protection Zener diode 67 (e.g., with a Zener voltage of 6.5V) are connected in parallel between the output terminals 34a and 34b.

[0044] Although the rectifier circuit 4 is configured using discrete diodes, it may also be configured using a dedicated IC. Figure 20 and Table 1 show the results of measuring the forward voltage Vf and reverse current Is of the diodes used in the rectifier circuit 4. For diode part number 1N60, silicon and germanium diodes were measured, and for the other part number ISS108, germanium diodes from different manufacturers were used for evaluation. In Figure 20, curve 42 is the characteristic of 1N60 (silicon), curve 41 is the characteristic of 1N60 (germanium), and curve 43 is the characteristic of ISS108 (germanium).

[0045] [Table 1]

[0046] The reverse current Is is the current that flows when a voltage is applied in the reverse direction of a diode. The measurement data in Table 1 is from when 10 V is applied in the reverse direction of the diode. The forward voltage Vf is the voltage at which forward current (1 mA) begins to flow through the diode.

[0047] When the output of the antenna section 1a described above is rectified, it was found that a 1N60 (silicon) diode, which does not allow reverse current to flow, can capture more power than a diode with a lower forward current flow voltage. Because the input to be rectified is AC, the reverse current Is when the diode's forward voltage Vf is applied in the reverse direction is calculated using the 10V data in Table 1. When a voltage equal to Vf is applied in the reverse direction, the reverse current Is is calculated to be 0.036 μA for the 1N60 (silicon), 0.21 μA for the 1N60 (germanium), and 0.5 μA for the ISS108 (germanium). Therefore, the ratio of reverse current Is at a forward current (1 mA) / forward voltage Vf is calculated to be 1 / 27778 for the 1N60 (silicon), 1 / 4762 for the 1N60 (germanium), and 1 / 2000 for the ISS108 (germanium). In other words, the diode used in the rectifier circuit 2 must have the above ratio greater than approximately 4700, and preferably the ratio is greater than or equal to 10000. As a result, of the three diodes given as examples, 1N60 (silicon) has the most suitable characteristics.

[0048] Furthermore, considering the characteristics of a diode, the smaller the reverse current Is when voltage is applied in the reverse direction, the better. Using data from 10V, the reverse resistance values ​​are calculated to be 100 MΩ for 1N60 (silicon), 1.43 MΩ for 1N60 (germanium), and 0.38 MΩ for ISS108 (germanium). In other words, a diode with a large resistance value that blocks reverse current flow is preferable, and the diode used in rectifier circuit 2 must have the above-mentioned resistance value greater than 1.43 MΩ, preferably 10 MΩ or greater. As a result, of the three example diodes, 1N60 (silicon) has the most suitable characteristics.

[0049] Taking into account such differences in diode characteristics, it is possible to provide two rectifier circuits 2a and 2b and separate the output of the antenna unit 1a into two frequency components using a diplexer 7, as shown in Figure 21. The low-frequency components separated by the diplexer 7, below a predetermined frequency, for example, below 1 MHz, are supplied to one rectifier circuit 2a and rectified. The high-frequency components above the predetermined frequency, for example, above 1 MHz, are supplied to the other rectifier circuit 2b and rectified. The outputs of these rectifier circuits 2a and 2b are added together by an adder circuit 8 and output.

[0050] The rectifying diodes constituting the rectifier circuit 2a have characteristics suitable for rectifying electrical signals generated from a quasi-electrostatic field of low frequency components, such as a small reverse current Is at a forward voltage Vf, while the rectifying diodes constituting the rectifier circuit 2b have characteristics suitable for rectifying electrical signals generated from radio waves in a radiated electromagnetic field of high frequency components, such as a low forward voltage. The diplexer 7 that separates the frequency of the output signal from the antenna unit 1a is constructed with as little loss as possible. Note that the predetermined frequency of 1 MHz is merely an example, and the signal may be divided into different frequencies depending on the diode frequency characteristics, or the frequency division may be three or more divisions.

[0051] The configuration of an antenna device using a full-wave rectifier circuit as the rectifier circuit will be described. Fig. 22 shows a configuration corresponding to that of Fig. 6. Note that the varistor 18 may be connected between the output terminal 34a and the ground 19. Fig. 23 shows a configuration corresponding to that of Fig. 7. Note that the varistor 21 may be connected between the output terminal 34a and the ground 19. Fig. 24 shows a configuration corresponding to that of Fig. 9. Note that the varistor 21 may be connected between the output terminal 34a and the ground 19. In this way, the full rectifier circuit 2 can be used in the same way as a voltage doubler rectifier circuit.

[0052] According to the embodiment of the present technology described above, by contacting or connecting the antenna element to a metal, it is possible to capture energy of quasi-electrostatic fields and radio waves generated in space. If the captured energy is rectified and stored in a storage element such as a secondary battery, it can be used as a power source for indoor and outdoor sensors.

[0053] 25, a full-wave rectifier circuit (comprising diodes 61 to 64 and Zener diodes 66 and 67) is connected to antenna device 1, and the output voltage of the full-wave rectifier circuit can be measured by a high-resistance sensor (2 MΩ or more, preferably 10 MΩ), such as a voltmeter 95. In addition, a battery 96 is charged by the output of the full-wave rectifier circuit via backflow prevention diode 65, and the output of battery 96 is used as the power source for voltmeter 95.

[0054] By using a high-resistance sensor, it is possible to measure the voltage induced in metal. Then, by analyzing the acquired data, it is possible to obtain information such as the operating status of the equipment's motor and inverter. This makes it possible to grasp the equipment's condition and issue alerts before a breakdown occurs.

[0055] As an example, an experiment was conducted by attaching an antenna device to the side of a refrigerator. The generated power of 4.4V was used to charge the battery by stepping down the voltage from 3.7V to 2.5V using a step-down DC-DC converter. The results of checking the charging voltage and input voltage at regular intervals are shown in the graph in Figure 26. This graph shows that the battery is being charged and that the timing to turn off the inverter can be detected.

[0056] Another embodiment of the present technology will be described with reference to Figs. 27A, 27B, and 28. In this other embodiment, the present technology is applied to a vehicle (particularly a vehicle body). As shown in Fig. 27A, when the antenna device 1 (hatched portion) is attached to a vehicle 71, it can be considered that a large antenna device 1 is configured by capacitive coupling between the ground of the equipment board 12 or the separate second antenna element 20 and the ground in the configurations of Figs. 5 and 7. This antenna device 1 is capable of receiving quasi-electrostatic fields and the energy of radio waves generated in space, including receiving low-frequency quasi-electrostatic fields.

[0057] Generally, cars (car bodies) are made of metal, making them prone to static electricity. Recently, to improve tire wear resistance, silica has been mixed into tires instead of conventional carbon. Because silica does not conduct electricity, measures have been taken to dissipate static electricity, such as creating conductive slits 74 (shown with diagonal lines) in parts of the tire 73, as shown in the enlarged cross-section of Figure 28. The conductive slits 74 allow static electricity to escape. However, because the contact area of ​​the conductive slits 74 with the ground is limited, the tire has a resistance value of approximately 10 MΩ. In other words, the circuit configuration is grounded by a resistor, as shown in Figure 27B. Therefore, from the perspective of the quasi-electrostatic field and radio wave energy generated in the space under consideration, the tire appears to be floating in space. Even if the tire is not completely insulated from the ground, although Figure 19B shows an example of a resistor, the connection between the metal part (e.g., car body) 72 and the ground may be connected by an inductance component instead of a resistor.

[0058] By using a large metal part of a car as an antenna in this way, it becomes possible to capture more of the quasi-electrostatic field and radio wave energy generated in the air. If the captured energy is rectified and stored in a storage element such as a secondary battery, it will no longer be necessary to charge sensors that detect the position of the car key, which will be necessary in cars in the future.

[0059] This technology uses metal objects such as cars, vending machines, refrigerators, microwave ovens, metal racks, guardrails, mailboxes, and traffic lights as antennas. Furthermore, by combining this antenna with the ground of the receiving device or a separate antenna, the receivable frequency is not limited by the antenna's shape. Furthermore, by capacitively coupling the ground of the receiving device to the earth's surface, it is possible to capture electric field energy in quasi-electrostatic fields other than radio waves. This means that it is possible to convert power and noise leaking from power cords and inverters into energy. In this way, the metal of the product can be treated as a single antenna element, and the power induced in the metal itself can be captured as an antenna between the receiving device's ground and the metal.

[0060] Assuming that indoor microwave ovens, refrigerators, etc. draw power from metal products that need to be grounded as a static electricity countermeasure, static electricity countermeasures can be achieved by inserting an electrostatic protection component, such as a varistor 21, between the antenna element 11 and the equipment, and connecting insulated cables 24, 25a, 25b via the equipment ground 19 or the antenna element 20, and grounding them to the earth ground, as shown in the examples of Figures 6, 8, 9, 10, and 11.

[0061] 9, the antenna element 20 is connected to the ground via an insulating cable, which makes it possible to extract much more power than with capacitive coupling. When extracting power from the metal part of such a product, it is necessary to connect it using an insulating cable or the like, as described above.

[0062] Although the embodiments of the present technology have been specifically described above, they are not limited to the above-described embodiments, and various modifications based on the technical concept of the present technology are possible. Furthermore, one or more arbitrarily selected modifications can be combined as appropriate. Furthermore, the configurations, methods, processes, shapes, materials, and numerical values ​​of the above-described embodiments can be combined with each other without departing from the spirit of the present technology. For example, the present technology may be used in combination with natural energy-based power generation, such as solar power generation, or a thermoelectric conversion element to store energy.

[0063] Next, as an application example of the receiving device according to the embodiment, it can be used as a power supply device for electronic devices such as a temperature and humidity sensor, a car position detection sensor, etc.

[0064] Fig. 29 is a block diagram showing an example application of the present technology to a power supply for IoT (Internet of Things) for environmental monitoring or device condition detection. The device has an illuminance sensor 51, a temperature, humidity, and atmospheric pressure sensor 52, a BLE (Bluetooth (registered trademark) Low Energy) sensor, and an MCU (Microcontroller unit) 53, and these blocks (ICs) are connected via an I2C bus 54. An antenna device 1 (configured as shown in Fig. 6 and consisting of an antenna unit 1a and a rectifier circuit 2) according to the present technology is applied as a power supply for such IoT.

[0065] Furthermore, if the rectifier circuit 2 uses a capacitor, for example a voltage doubler rectifier circuit, it is important that the leakage current of the diode when reverse biased is very small. If there is leakage current, a full-wave rectifier circuit is suitable. The diode characteristics should be such that it can pass a large current even at a very low voltage Vf. Furthermore, to obtain a high voltage, it is desirable that the leakage current of the reverse voltage applied substrate is very small. When using a circuit such as a quadruple voltage, the leakage current should be around 0.001 μA when a reverse voltage of 5 V is applied.

[0066] Furthermore, if rectifier circuit 2 is a voltage doubler rectifier circuit or larger that uses a capacitor, it is important that the leakage current of the diode when reverse biased is very small. If there is leakage current, a full-wave rectifier circuit is suitable. The diode characteristics should be such that it can pass a large current even at a very low voltage Vf. Furthermore, to obtain high voltages, it is desirable that the leakage current of the reverse voltage application substrate is very small. When using a circuit such as a quadruple voltage, the leakage current should be around 0.001 μA when a reverse voltage of 5 V is applied.

[0067] BLE is an extended specification of Bluetooth (registered trademark) that enables communication with extremely low power. BLE and the MCU 53 enable wireless transmission of detection data from the illuminance sensor 51 and the temperature, humidity, and atmospheric pressure sensors 52 to a mobile device such as a smartphone or tablet.

[0068] Output terminals 34a and 34b of rectifier circuit 2 are connected to a DC-DC converter 55 serving as a charger. A power storage element, such as a lithium ion secondary battery 56, is charged by the output of DC-DC converter 55. The output of lithium ion secondary battery 56 is supplied to DC-DC converter 57 and LDO (Low Dropout) 58.

[0069] The output of the DC-DC converter 57 is supplied as power to the illuminance sensor 51, temperature, humidity and atmospheric pressure sensor 52, BLE and MCU 53. In addition, the output of the LDO 58 is supplied as power to the BLE and MCU 53. The LDO is a linear regulator that can operate even with a low input-output voltage difference, and by operating at a low voltage difference, it is possible to design with less energy loss and reduced heat generation. The output voltage of the secondary battery 56 is supplied to the AD conversion input of the BLE and MCU 53, and the BLE and MCU 53 monitor it.

[0070] Antennas used for external communications such as the above-mentioned BLE should preferably have a dipole structure, which is an antenna configuration that does not use the ground of the circuit board and is less susceptible to the effects of energy harvesting.

[0071] By applying the above-mentioned storage circuit section, it is also possible to charge the batteries of devices that require charging.

[0072] When used outdoors and exposed to wind and rain, waterproofing, drip-proofing, and weather resistance to ultraviolet rays, etc. In the configurations of Figures 2 and 3, the weather resistance of the antenna device 1 can be improved by coating the surfaces of the antenna element 11 and case 17, or, when the cases are separated (Figure 2C), the cases 17A and 17B and joint 22, with a water-resistant and light-resistant resin.

[0073] Furthermore, this technology captures the energy of the electric field induced in the metal parts of the device, and if this effect is actively utilized, it can also be used as a wireless power receiving device.

[0074] A general configuration for further increasing the output of an antenna device including an antenna unit 1a and a rectifier circuit 2 will be described with reference to Figs. 30A and 30B. Fig. 30A shows a configuration in which antenna devices 101, 102, and 103 are connected in series. The voltage VL applied to a load RL is (V1+V2+V3). Fig. 30B shows a configuration in which antenna devices 101, 102, and 103 are connected in parallel. The current IL flowing through the load RL is (I1+I2+I3).

[0075] FIG. 31 shows a first embodiment for increasing the output voltage of an antenna device. A first antenna element 11 is provided in contact with a metal, and two second antenna elements 20A and 20B are provided for the antenna element 11. The antenna elements 20A and 20B are, for example, separate, independent substrates or housings. A rectifier circuit 2A is provided to rectify the output of the antenna unit consisting of the antenna elements 11 and 20A, and a rectifier circuit 2B is provided to rectify the output of the antenna unit consisting of the antenna elements 11 and 20B. The rectifier circuits 2A and 2B are connected in series, and an output line is derived from the series connection.

[0076] 32 shows the circuit connection of the first embodiment. In this example, full-wave rectifier circuits are used as the rectifier circuits 2A and 2B connected in series. Zener diodes 66 and 67 are common elements for the two rectifier circuits 2A and 2B.

[0077] According to the first embodiment, if an output voltage of, for example, 4 V is obtained from one antenna device, an output voltage of 8 V can be obtained. A larger output voltage can be obtained by connecting two or more rectifier circuits in series. The first embodiment is a suitable configuration for cases where the frequency of power supply noise or the like that induces voltage is low, since there is no need to consider the distance between antennas.

[0078] In the second embodiment, as shown in Figures 33 and 34, independent antenna elements 11A and 11B are provided as first antenna elements that are brought into contact with metal. The antenna elements 11A and 11B are brought into contact with different points on the metal.

[0079] 34 shows a circuit connection of the second embodiment. In this example, full-wave rectifier circuits are used as the rectifier circuits 2A and 2B connected in series. Zener diodes 66 and 67 are common elements for the two rectifier circuits 2A and 2B.

[0080] A third embodiment for increasing the output current of an antenna device is shown in Figures 35 and 36. A first antenna element 11 is provided in contact with metal, and two second antenna elements 20A and 20B are provided for the antenna element 11. The antenna elements 20A and 20B are, for example, separate, independent substrates or housings. A rectifier circuit 2A is provided to rectify the output of the antenna unit consisting of the antenna elements 11 and 20A, and a rectifier circuit 2B is provided to rectify the output of the antenna unit consisting of the antenna elements 11 and 20B. The rectifier circuits 2A and 2B are connected in parallel, and an output line is derived from the parallel connection.

[0081] 36 shows a circuit connection of the third embodiment. In this example, full-wave rectifier circuits are used as the rectifier circuits 2A and 2B connected in parallel. Zener diodes 66 and 67 are common elements for the two rectifier circuits 2A and 2B.

[0082] In the fourth embodiment, as shown in Figures 37 and 38, independent antenna elements 11A and 11B are provided as first antenna elements that are brought into contact with metal. The antenna elements 11A and 11B are brought into contact with different points on the metal.

[0083] Fig. 38 shows a circuit connection of the fourth embodiment. In this example, full-wave rectifier circuits are used as the rectifier circuits 2A and 2B connected in parallel. Zener diodes 66 and 67 are common elements for the two rectifier circuits 2A and 2B.

[0084] The antenna elements 11, 11A, and 11B that contact the metal are connected to the connection point of the diodes 61a and 64a and the connection point of the diodes 61b and 64b, respectively, to achieve the same phase. Also, the connection points of the full-wave rectifier circuits are the same. The antenna element connected to the metal element is connected at a position where the phases of the rectifier circuits are added together to make the phases the same.

[0085] 39A and 39B, 40A and 40B show examples of increasing the number of antennas in the present technology. Increasing the number of antennas of the same length will result in a slight decrease in voltage, but if you want to increase the current, you can increase the number of antenna elements. As shown in FIGS. 39A and 40A, the current can be increased by creating and connecting an antenna element 200 to the base of the antenna element 20. If you want to increase both the voltage and the current, the length of the antenna element is set to (length of antenna element 20<length of antenna element 200). Also, as shown in FIGS. 39B and 40B, the antenna element 20 may be created on a substrate on which a rectifier circuit is mounted, and the antenna element 200 may be created separately, for example, using a substrate, a housing, a rod antenna, or the like.

[0086] As mentioned above, if an output current of 4 μA can be obtained from one antenna device, an output current of 8 μA can be obtained by connecting the devices in a parallel circuit. Also, if you want to increase the voltage, for example, if you want to increase the output from 4 V to 8 V, this can be achieved by connecting the devices in a series circuit. In this way, by combining the above series and parallel circuits, it is possible to supply the required power to the subsequent stage.

[0087] In the above circuit configuration, a capacitor is used to smooth the rectified voltage. may be connected in parallel to the Zener diode. [Explanation of symbols]

[0088] 1...antenna device, 2, 2a, 2b...rectifier circuit, 4...storage element, 7...diplexer, 11...antenna element, 12...equipment board, 15...feed point, 91...metal rack, 71...vehicle

Claims

1. An antenna device comprising an antenna section including a rectifier circuit for receiving radio waves in space or electric field energy of a quasi-electrostatic field (near field) and rectifying the AC signal to DC, the antenna section being composed of a first antenna element which is a conductor that contacts or is connected to the metal part of an industrial product, and a second antenna element which is a conductor separate from the first antenna element and is arranged so as not to be electrically connected to the metal part of the industrial product, and the input line of the AC signal output from the antenna section, which is output from the first antenna element to the rectifier circuit section, is connected to the rectifier circuit.

2. 2. The antenna device according to claim 1, wherein the input line is connected in series with the rectifier circuit.

3. 2. The antenna device according to claim 1, wherein the second antenna element is capacitively coupled to a ground.

4. 2. The antenna device according to claim 1, wherein the second antenna element is grounded to the earth ground.

5. 2. The antenna device according to claim 1, wherein the contact surface of the first antenna element with the metal part of the industrial product is made of a conductor electrode made of any one or combination of gold, silver, aluminum, copper, iron, nickel, or an alloy.

6. The contact surface of the first antenna element with the metal part of the industrial product is formed by caulking, pressure welding, 6. The antenna device according to claim 5, wherein the antenna device is in contact with the metal part of the industrial product by any one or a combination of the above.

7. 6. The antenna device according to claim 5, wherein the conductor electrode is coated with a resin.

8. 2. The antenna device according to claim 1, wherein the connection portion of the first antenna element with the metal part of the industrial product is made of a conductor electrode made of one or a combination of gold, silver, aluminum, copper, iron, nickel, or an alloy.

9. 9. The antenna device according to claim 8, wherein the connection portion is connected by any one or a combination of screwing, soldering, welding, conductive resin, conductive tape, conductive rubber, and magnets.

10. 6. The antenna device according to claim 5, wherein the conductor electrode has any one of a pin shape, a line shape, a hemispherical shape, a concave and convex shape, and a flat shape, or a combination thereof.

11. 2. The antenna device according to claim 1, wherein the second antenna element is composed of one or a combination of the following: a ground of a circuit board of a receiver, a pattern separate from the ground on the board, a metal part of a receiver housing that is not electrically connected to the metal part of the industrial product, or a conductor cable.

12. 2. The antenna device according to claim 1, wherein the second antenna element and the ground are directly or indirectly grounded using an insulating cable or the like.

13. 2. The antenna device according to claim 1, wherein the first antenna element connected to the metal part is grounded via an electrostatic protection component.

14. 2. The antenna device according to claim 1, wherein the first antenna element is connected to the ground by an insulating cable via an electrostatic protection component.

15. 2. The antenna device according to claim 1, further comprising: a separation circuit for frequency-separating an AC signal input from said antenna section; and a plurality of rectification circuits for rectifying each of the AC signals separated by said separation circuit.

16. 2. The antenna device according to claim 1, wherein the contact surface of the metal part of the industrial product other than the contact or connection part is housed in a case made of an insulating material.

17. An antenna device having a rectifier circuit in which the ratio of the forward current when a forward voltage is applied to a rectifying diode to the reverse current when that voltage is applied in the reverse direction is at least 4700 times or more.

18. An antenna device having a rectifier circuit in which the resistance value measured using a reverse current when 10 V is applied in the reverse direction of a rectifying diode is 1.4 MΩ or more.

19. 18. The antenna device according to claim 17, wherein the antenna device captures electric field energy of radio waves and / or quasi-electrostatic fields (near fields) in space.

20. 18. A rectifier circuit according to claim 17, wherein the diode is made of silicon.

21. an antenna device including a rectifier circuit for receiving electric field energy of radio waves or quasi-electrostatic fields (near fields) in space and rectifying AC signals into DC, the antenna unit being composed of a first antenna element which is a conductor that contacts or is connected to the metal part of the industrial product, and a second antenna element which is a conductor separate from the first antenna element and is provided so as not to be electrically connected to the metal part of the industrial product, the antenna device having an input line that outputs AC signals output from the antenna unit from the first antenna element to the rectifier circuit unit and connected to the rectifier circuit; and a storage element that is charged by the output of the rectifier circuit. An electronic device comprising a communication unit powered by the output of the storage element.

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