Antenna equipment, power supply equipment, and electronic equipment

Abstract

This antenna device is provided with a rectifier circuit which receives radio waves in space and the electric field energy of a quasi-electrostatic field and rectifies an AC signal to DC, and comprises an antenna unit which is configured from a first antenna element which is used in contact with a human body in a state in which the human body is not grounded to a ground that is the earth, and a second antenna element which is a separate conductor from the first antenna element and which is provided so as not to contact the human body. An input line for outputting to the rectifier circuit the part of the AC signal outputted from the antenna unit that is from the first antenna element used in contact with the human body, is connected in series with the rectifier circuit. FIG. 2

Description

Technical Field

[0001] This technology relates to an antenna device and an electronic device having an energy harvesting function. station, electric

Background Art

[0002] It is conceivable to convert the energy of radio waves such as broadcast waves existing around us into electric power (energy harvesting). In conventional energy harvesting using radio waves, in order to capture the electric power in space, an antenna is formed according to the frequency of the received radio wave, and a rectifier circuit is connected to this to accumulate energy. In this method, antennas according to the received frequencies are required, and the electric power that can be captured as energy is limited.

[0003] Patent Document 1 describes capturing the energy of radio waves from space by making the human body function as an antenna or a ground.

[0004] There is described a method of providing an input terminal portion for capturing the electromagnetic energy of radio waves that propagate in the air through the human body in contact with the human body, rectifying the electric power of the AC waveform input from the input terminal, converting it into a DC waveform, and charging a storage battery as electric power. An impedance matching portion for impedance matching with an antenna is provided between the input terminal and the rectifier circuit, and it is composed of a resistor, a capacitor, an inductor, etc.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] ​The problem with Patent Document 1 is that it only considers the electromagnetic energy of radio waves propagating through the air, and by including a matching section to match the impedance with the antenna, which includes the human body, the amount of power that can be received is significantly reduced. Experimental results in Patent Document 1 showed that only about 100 μV per minute could be obtained at maximum, severely limiting its range of applications. This technology solves that problem.

[0007] This technology utilizes a design where the input terminal, which contacts the human body to act as an antenna, is connected in series with the subsequent rectifier circuit without a matching circuit, as the human body can handle a wide range of frequencies. Rectification is performed using a diode with a very small reverse current relative to the forward current. This allows for efficient reception of not only conventional radio waves, but also very low-frequency electric fields (a few Hz) generated when a person walks, and quasi-electrostatic (near-field) power (50 / 60 Hz) leaking from power sources. In other words, the antenna shape does not need to be considered between the input terminal connected to the human body and the rectifier circuit, eliminating the need for a matching circuit. This allows the antenna device's ground, or a separate antenna element, to create an electric field with the earth's ground via capacitor coupling, enabling the capture of electric field energy from quasi-electrostatic fields other than radio waves. Specifically, it allows for the reception of power and noise leaking from power cords and inverters, converting them into energy. This means that the received power can be increased by receiving a wide range of electric field energy. A quasi-electrostatic field is a voltage phenomenon that does not propagate like a radiated electromagnetic field, or radio waves, but rather distributes around people, vehicles, or materials in a manner similar to electrostatic charging. While an electrostatic field is considered to have zero time variation, a quasi-electrostatic field has frequency components and is subject to time variation.

[0008] Therefore, the objective of this technology is to create an antenna that can obtain greater received power by incorporating not only radio waves present over a wide area but also the electric field energy of a quasi-electrostatic field (near-field), in a configuration different from conventional methods that use the human body to convert radio wave energy into electricity. station, electricThe objective is to provide power source devices and electronic equipment. [Means for solving the problem]

[0009] This technology includes a rectifier circuit for receiving electric field energy from radio waves or quasi-electrostatic fields in space and rectifying AC signals into DC signals, and an antenna section comprising a first antenna element, which is a conductor used in contact with the human body when the human body is not grounded to the earth, and a second antenna element, which is a conductor separate from the first antenna element and is provided so as not to come into contact with the human body. This antenna device has an AC signal output from the antenna section, and the input line from the first antenna element, which is used in contact with the human body, is connected in series with the rectifier circuit without any matching circuit. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a block diagram of one embodiment of a receiving device based on this technology. [Figure 2] Figures 2A, 2B, and 2C are plan and cross-sectional views of the antenna device included in the receiving device. [Figure 3] Figure 3 is a schematic diagram illustrating an example of an antenna device including a circuit board. [Figure 4] Figure 4 is a schematic diagram illustrating another example of an antenna device including a circuit board. [Figure 5] Figures 5A, 5B, and 5C are schematic diagrams showing specific examples of the second antenna element. [Figure 6] Figures 6A and 6B are schematic diagrams illustrating the operation of the antenna device. [Figure 7] Figure 7 is a connection diagram showing an example of a rectifier circuit configuration. [Figure 8] Figure 8 is a connection diagram showing the configuration of another example of a rectifier circuit. [Figure 9] Figure 9 is a graph illustrating the characteristics of the diodes in the rectifier circuit. [Figure 10] FIG. 10 is a block diagram of a modification of an embodiment. [Figure 11] FIGS. 11A, 11B, and 11C are graphs showing measurement results of an output of an embodiment. [Figure 12] FIGS. 12A and 12B are graphs showing measurement results of an output of an embodiment. [Figure 13] FIGS. 13A and 13B are graphs showing measurement results of peak gain measurement of an embodiment. [Figure 14] FIGS. 14A and 14B are graphs showing measurement results of peak gain measurement of an embodiment. [Figure 15] FIG. 15 is a schematic diagram used to explain the operation of an embodiment. [Figure 16] FIG. 16 is a waveform diagram showing an example of a waveform of a voltage generated by a human body. [Figure 17] FIG. 17 is a block diagram of an embodiment of a power supply device according to the present technology. [Figure 18] FIG. 18 is a block diagram of another embodiment of a power supply device according to the present technology. [Figure 19] FIG. 19 is a flowchart for explaining the operation of a power supply device according to the present technology. [Figure 20] FIGS. 20A and 20B are schematic diagrams showing the configuration of an application example in which the present technology is applied to the operation of a notebook personal computer. [Figure 21] FIG. 21 is a graph showing an example of a voltage change obtained by the configuration of FIG. 20. [Figure 22] FIG. 22 is a block diagram of still another embodiment of a power supply device according to the present technology. [Figure 23] FIG. 23 is a block diagram of yet another embodiment of a power supply device according to the present technology. [Figure 24] FIGS. 24A and 24B are block diagrams showing a general configuration for increasing an output. [Figure 25] FIG. 25 is a block diagram of an example of a configuration in which antenna devices are connected in series. [Figure 26]Figure 26 is a connection diagram showing an example of the circuit connection shown in Figure 25. [Figure 27] Figure 27 is a block diagram of another example of a configuration in which antenna devices are connected in series. [Figure 28] Figure 28 is a connection diagram showing an example of the circuit connection shown in Figure 27. [Figure 29] Figure 29 is a block diagram of an example of a configuration in which antenna devices are connected in parallel. [Figure 30] Figure 30 is a connection diagram showing an example of the circuit connection in Figure 29. [Figure 31] Figure 31 is a block diagram of another example of a configuration in which antenna devices are connected in parallel. [Figure 32] Figure 32 is a connection diagram showing an example of the circuit connection in Figure 31. [Figure 33] Figures 33A and 33B are schematic diagrams used to explain the case where the number of antennas is increased. [Figure 34] Figures 34A and 34B are connection diagrams used to explain how to increase the number of antennas. [Modes for carrying out the invention]

[0011] The embodiments described below are preferred examples of the present technology and are subject to various technically preferred limitations. However, the scope of the present technology is not limited to these embodiments unless otherwise specified in the following description. Furthermore, in the following description, the same names and reference numerals indicate the same or identical components, and redundant explanations are omitted as appropriate.

[0012] Figure 1 shows one embodiment of an antenna device equipped with an energy harvesting function according to this technology. The antenna section 1a, consisting of a first antenna element and a second antenna element, receives electric field energy, and the output of the antenna section 1a is supplied to the rectifier circuit 2. The antenna device 1 is composed of the antenna section 1a and the rectifier circuit 2.

[0013] The output of the rectifier circuit 2 is supplied to the charger 3. The energy storage element 4 is connected to the charger 3. The energy storage element 4 is charged by the charger 3. The charger 3 may also control the discharge of the energy storage element 4. The antenna device 1, charger 3, and energy storage element 4 constitute a receiving device. A load 5 is connected to the energy storage element 4. The load 5 operates using the power stored in the energy storage element 4. The load 5 is, for example, a microcomputer, a wireless communication unit, or a sensor. The output of the sensor is transmitted wirelessly under the control of the microcomputer.

[0014] Antenna device 1 consists of a first antenna element and a second antenna element that come into contact with the human body. The antenna device will be described with reference to Figures 2A (plan view), 2B (cross-sectional view), and 2C (cross-sectional view), which show the first antenna element, antenna element 11, configured as a plate (patch), and Figure 3 (circuit board view) on which the rectifier circuit 2 (explained later) is mounted. As shown in Figures 2A, 2B, and 2C, the antenna element 11 as the contact part is a plate made of a conductor such as gold, silver, aluminum, copper, iron, nickel, or an alloy. The antenna element 11 is a conductor and may also be electrically conductive, such as a conductive resin or conductive rubber compounded with carbon or metal. For example, using gold or silver makes it possible to construct a low-resistance electrode. Using aluminum, copper, iron, nickel, etc., makes it possible to reduce the cost of the antenna element 11. Furthermore, using these metals or alloys with other metals makes it possible to construct lightweight electrodes or highly durable electrodes as appropriate. Furthermore, the antenna element 11 may be made of a conductive resin or conductive rubber, for example, a material containing carbon or metal. Using a conductive resin makes it easy to form electrodes of various shapes. Using conductive rubber makes it possible to construct electrodes that can be elastically deformed or electrodes with high adhesion. Furthermore, the material of the antenna element 11 is not limited; the materials described above may be used individually, or the electrodes may be constructed by combining the materials.

[0015] Furthermore, the antenna element 11 may be configured so that the conductors constituting the electrodes directly contact the human body, or the surface that contacts the human body may be coated with a resin. The coating may use a resin that is water-resistant, such as waterproof or drip-proof, and weather-resistant to ultraviolet rays, etc. This prevents the antenna element 11 from corroding when used outdoors or in a swimming pool, etc. In addition, it is possible to protect the antenna element 11 from sweat and moisture generated when the user exercises.

[0016] In Figures 2B and 2C, for example, a plate-shaped (patch-shaped) antenna element 11 and a device substrate (circuit board) 12 are arranged opposite each other, with a dielectric plate 13 interposed between the antenna element 11 and the device substrate 12. Alternatively, the dielectric plate 13 may be omitted, leaving a space between the antenna element 11 and the device substrate 12.

[0017] To electrically connect the antenna element 11 and the equipment circuit board 12, one end of the antenna element 11 and a conductive pin 14 are electrically connected, and the other end of the conductive pin 14 penetrates the equipment circuit board 12 and is soldered to the signal path electrode on the back surface of the equipment circuit board 12. The antenna section 1a is formed by the ground created by the copper foil pattern of the antenna element 11 and the equipment circuit board 12. The ground is the second antenna element.

[0018] The connection point between the signal path electrodes of the equipment board 12 and the conductive pins 14 becomes the feed point 15 of the antenna. A circuit section 16 is provided on the back surface of the equipment board 12, for example. The circuit section 16 includes a rectifier circuit 2. The rectifier circuit 2 is designed so as not to overlap with the ground 19 formed by the copper foil pattern of the equipment board 12. A charger 3 and an energy storage element 4 (not shown) may be included within the circuit section 16, or they may exist as separate components.

[0019] The antenna device with the above configuration is housed inside the case 17. The surfaces of the case 17 that come into contact with the human body, other than the antenna element 11, are made of insulating material such as resin. Furthermore, the sides and opposite sides of the case, other than those in contact with the human body, are also made of insulating material.

[0020] Figure 2C shows that the case 17 consists of a non-metallic case 17A made of resin or the like and a metal case 17B. It is also possible to configure the case 17B to be electrically connected to the ground 19 on either the upper or lower surface of the equipment circuit board 12. That is, the insulating material case 17A on which the antenna element 11 is provided and the metal material case 17B on the opposite side may be connected by a connector 22 such as a screw, and the case 17B and the ground 19 of the equipment circuit board 12 may be connected by a wire 23.

[0021] As shown in Figure 3, a ground 19 formed by a copper foil pattern is formed on the circuit board 12, and the antenna section 1a is composed of the antenna element 11 and the ground 19 formed by the copper foil pattern of the equipment board 12. The ground 19 is the second antenna element. Furthermore, as a measure against static electricity, an electrostatic discharge protection component, such as a varistor 18, is inserted between the antenna element 11, which comes into contact with or is connected to the human body, and the ground formed by the copper foil pattern of the receiving equipment. The varistor 18 may also be connected between the output terminal 34a and the ground 19.

[0022] The circuit section 16 includes a rectifier circuit 2. The rectifier circuit 2 is configured so as not to overlap with the ground 19 formed by the copper foil pattern on the equipment board 12. The input line output from the antenna element 11 to the rectifier circuit 2 is connected in series with the rectifier circuit without going through a matching circuit. The circuit section 16 may include a charger 3 and an energy storage element 4 (not shown), or they may exist as separate components.

[0023] Next, a separate second antenna element 20 (shown as a shaded area) formed of a copper foil pattern may be constructed on the above substrate, as shown in Figure 4. In this case, the separate second antenna element 20 must not come into contact with the human body. Although it is shown on a separate substrate in Figure 4, it may also be formed on a metal part such as a housing that is configured not to come into contact with the human body, in contrast to the receiver's human body. In this case as well, an electrostatic discharge protection component, such as a varistor 21, can be inserted between the antenna element 11 that comes into contact with the human body and the ground of the receiving equipment as a measure against electrostatic discharge.

[0024] Other configurations of the second antenna element 20 are shown in Figure 5. Figure 5A shows the configuration of the meander line 20a, and Figure 5B shows the configuration of the coil 20b, which may also be a tip coil configuration. Figure 5C shows a configuration with an inductor 20c at the tip. These configurations can reduce the occupied area, increase the antenna length, and increase the induced voltage.

[0025] A great deal of electric field energy exists around us, but it can be divided into low-frequency and high-frequency components. For example, leakage electric fields from household AC power (50Hz / 60Hz), noise near personal computers, and voltage generated when people walk are low-frequency components. These are called quasi-electrostatic fields (near-field). 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-field).

[0026] The antenna element 11 of the antenna section 1a described above is made to come into contact with the human body. The antenna element 11 is attached to a part of the human body, such as the arm. By using the human body as an antenna, the antenna device 1 can capture energy from both quasi-electrostatic fields such as noise, which is leakage current, and radio waves such as broadcast waves.

[0027] As shown in Figure 5A, electrically, the human body and the antenna element 11 are in capacitive contact. For the antenna device 1, it is preferable for the antenna element 11 to be in direct contact with the human body, but basically, it is preferable for the contact to be over a surface so that the capacitance is large. However, it is not limited to a surface; as long as it is in contact with the human body, it may be a pin structure, hemispherical, or interlocking structure other than a flat surface. The antenna device 1, which is composed of the antenna element 11 in contact with the human body and the ground electrode of the equipment substrate 12, or a separate second antenna element 20 (Figure 4), can receive electric field energy and generate power.

[0028] Furthermore, as shown in Figure 5B, when the antenna device 1 (shaded portion) is attached to the arm, for example, it can be considered that a pseudo-ground is formed by capacitive coupling between the ground of the equipment board 12, or between the separate second antenna element 20 (Figure 4) and the ground of the earth. This antenna device 1 can receive quasi-electrostatic fields of low frequency. The reason why the antenna device 1 of one embodiment of this technology resonates at a low frequency such as 50 Hz is thought to be because blood vessels are being perceived as antennas. Thus, the antenna device 1 includes the antenna configuration shown in Figure 3 or Figure 4, and is capable of receiving radio waves over a wide frequency range. Therefore, electric field energy can be captured without being restricted by the location of the person wearing the antenna device according to this technology.

[0029] An example of rectifier circuit 2 is shown in Figure 6. When dealing with small voltages such as those used in energy harvesting, it is possible to rectify them using a normal rectifier circuit (not shown here), but a certain voltage is required to store energy quickly. Therefore, it is necessary to boost the voltage and rectify it, like in a voltage doubler circuit. Thus, by inserting a capacitor of the desired voltage boost level before the diode and rectifying, the voltage equivalent to that of the capacitor is added, making it possible to boost the voltage. Therefore, a full-wave quadruple voltage doubler rectifier circuit configuration consisting of input capacitors 26 and 27 connected to the antenna section 1a, diodes 28, 29, 30 and 31, and capacitors 32 and 33 was used. DC is output from both ends of the series connection of capacitors 32 and 33 to the output terminals 34a and 34b. In this configuration, capacitors 32 and 33 not only boost the voltage but also actually store current, so it is best to have a large capacitance and low leakage current in this part.

[0030] This example uses a full-wave quadruple voltage rectifier circuit, but other rectifier circuits incorporating standard half-wave, full-wave, voltage-doubler, or Cockcroft-Walton circuits (not shown here) may also be used. Furthermore, the full-wave rectifier circuit is more efficient because it can increase the voltage of the AC signal and capture all of it. Therefore, even considering the diode losses, the full-wave rectifier circuit yielded better results with the diodes used in this example. The configuration in Figure 7 is a two-stage quadruple voltage rectifier, but the number of stages can be increased further if a higher voltage output is desired.

[0031] An example of the values ​​for each element is shown below. Capacitors 26, 27: 0.22μF, 32, 33: 47μF Diodes 28, 29, 30, 31: 1N60 (silicon)

[0032] In the case of a capacitor-based rectifier, such as a voltage doubler rectifier, it is important that the diode leakage current during reverse bias is very small. If there is leakage current, a full-wave rectifier is suitable. Another example of rectifier circuit 2 (full-wave rectifier) ​​is shown in Figure 8. As shown in Figure 8, diodes 61 and 64 are connected in series, and diodes 63 and 62 are connected in series. The connection point of the anode of diode 61 and the cathode of diode 64 is connected to the first antenna element 11, and the connection point of the anode of diode 63 and the cathode of diode 62 is connected to the second antenna element 20. The connection point 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 connection point of the anode of diode 64 and the anode of diode 62 is connected to the other output terminal 34b. A varistor 66 for electrostatic discharge protection and a Zener diode 67 for IC protection (e.g., Zener voltage of 6.5V) are connected in parallel between output terminals 34a and 34b.

[0033] Although discrete diodes were used, a dedicated IC could also be used. Figure 9 and Table 1 show the results of measuring the forward voltage Vf and reverse current Is of the diodes used in rectifier circuit 2. For diode part number 1N60, silicon and germanium diodes were measured, while for other part number ISS108, germanium diodes from different manufacturers were used for evaluation. In Figure 9, curve 42 represents the characteristics of 1N60 (silicon), curve 41 represents the characteristics of 1N60 (germanium), and curve 43 represents the characteristics of ISS108 (germanium).

[0034] [Table 1]

[0035] The reverse current Is is the current that flows when a voltage is applied in the reverse direction to a diode. The measurement data in Table 1 is for when 10V is applied in the reverse direction to the diode. The forward voltage Vf is the voltage at which the forward current (1mA) begins to flow through the diode.

[0036] When the output of the antenna section 1a (a device using the human body as an antenna) described above is rectified, it was found that the diode 1N60 (silicon), which does not allow current to flow in the reverse direction, can capture more power than diodes with a lower voltage at which current begins to flow in the forward direction. Since the input being rectified is AC, the reverse current Is when the forward voltage Vf of the diode is applied in the reverse direction can be calculated from the data in Table 1 for 10V. When the same voltage as Vf is applied in the reverse direction, the reverse current Is is 0.036 μA for 1N60 (silicon), 0.21 μA for 1N60 (germanium), and 0.5 μA for ISS108 (germanium). Therefore, the ratio of forward current (1 mA) / reverse current Is is calculated to be 1 / 27778 for 1N60 (silicon), 1 / 4762 for 1N60 (germanium), and 1 / 2000 for ISS108 (germanium). In other words, the diode used in rectifier circuit 2 needs to have a ratio greater than approximately 4700 times, and preferably, a ratio of 10000 or more. As a result, among the three diodes given as examples, 1N60 (silicon) has the most suitable characteristics.

[0037] Furthermore, considering the characteristics of the diode, a smaller reverse current Is is preferable when current is applied in the reverse direction. Using 10V data, the reverse resistance values ​​are calculated to be 100MΩ for 1N60 (silicon), 1.43MΩ for 1N60 (germanium), and 0.38MΩ for ISS108 (germanium). In other words, a higher resistance value is preferable to prevent current from flowing in the reverse direction. For the diode used in rectifier circuit 2, the aforementioned resistance value must be greater than 1.43MΩ, preferably 10MΩ or more. As a result, among the three diodes given as examples, 1N60 (silicon) has the most suitable characteristics.

[0038] Taking into account the differences in diode characteristics, as shown in Figure 10, it is also possible to provide two rectifier circuits 2a and 2b and split the output of the antenna section 1a into two frequency components using a diplexer 7. The lower frequency component, below a predetermined frequency, for example, below 1 MHz, separated by the diplexer 7, is supplied to one rectifier circuit 2a and rectified. The higher frequency component, above the predetermined frequency, for example, above 1 MHz, is 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.

[0039] The rectifier diodes constituting the rectifier circuit 2a have characteristics suitable for rectifying electrical signals generated from quasi-electrostatic fields with low frequency components, for example, a low reverse current Is at a forward voltage Vf. The rectifier diodes constituting the rectifier circuit 2b have characteristics suitable for rectifying electrical signals generated from radio waves of radiated electromagnetic fields with high frequency components, for example, a low forward voltage. The diplexer 7 that frequency-separates the output signal of the antenna section 1a is constructed to minimize losses as much as possible. Note that the predetermined frequency of 1 MHz is just an example, and the frequency division may be set to different frequencies depending on the diode frequency characteristics, or the frequency division may be set to three or more divisions.

[0040] Figure 11 shows the waveform of the received signal obtained when an antenna device according to one embodiment of this technology was actually operated in a windowless laboratory owned by the applicant. Figures 11A, 11B, and 11C are spectra obtained by measuring the received signal in the frequency range of 25MHz to 500MHz indoors using a spectrum analyzer. Figure 11A is the received signal spectrum when the antenna device 1 is not connected, and for example, the received level at 100MHz (indicated by the square mark) is (-91.37dBm). dBm is a unit expressed in decibels (dB) with 1 milliwatt (mW) of power as the reference value, and represents the strength of radio waves. Figure 11B is the received signal spectrum when the antenna device 1 is used alone, and the received level at 100MHz (indicated by the square mark) is (-79.77dBm, 27.23dBμV). Figure 11C shows the received signal spectrum when the antenna device 1 is held in the hand, with a received level of (-72.15 dBm, 34.85 dBμV) at 100 MHz (indicated by the square mark). From Figures 11A, 11B, and 11C, it can be seen that the largest output signal is obtained when the antenna element 11 of the antenna device 1 is in contact with the human body.

[0041] Figures 12A and 12B show the results of an experiment in which radio waves, such as broadcast waves and mobile phone signals, were received outdoors. The results were obtained by receiving radio waves outdoors using an antenna device according to one embodiment of this technology and measuring the results with a spectrum analyzer. Figures 12A and 12B show the spectrum of the received signal in the frequency range of 50 MHz to 1 GHz outdoors. The vertical axis represents the strength of the radio wave (dBm). Figure 12A shows the received signal spectrum when the antenna device 1 is used alone, and Figure 12B shows the received signal spectrum when the antenna element 11 is held in the hand. Frequencies that yield relatively large amplitudes correspond to the frequency bands of FM broadcasting, television broadcasting, and mobile phones. These experimental results show that, both indoors and outdoors, the reception level increases significantly when the antenna element 11 of the antenna device 1 comes into contact with the human body.

[0042] Furthermore, Figures 13A and 13B show the measurement results (peak gain measurement) of the same antenna device 1 in an anechoic chamber. The horizontal axis represents frequency, and the vertical axis represents antenna gain (dBd). These measurement results are for the VHF band of FM broadcasting; Figure 13A shows the measurement results for the antenna alone, and Figure 13B shows the measurement results when the antenna element 11 is in contact with the hand. Furthermore, Figures 14A and 14B show the measurement results for the UHF band of television broadcasting; Figure 14A shows the measurement results for the antenna alone, and Figure 14B shows the measurement results when the antenna element 11 is in contact with the hand. From Figures 13A, 13B, 14A, and 14B, it can be seen that even in an anechoic chamber, the reception gain increases by bringing the antenna element 11 into contact with the human body. In these figures, thin lines represent the characteristics of horizontal polarization, and solid lines represent the characteristics of vertical polarization.

[0043] Furthermore, Figure 15 shows a floor structure (a so-called OA (office automation) floor) when floor wiring is installed. A metal floor plate 46 is supported by a metal plate support part 45 on a reinforced concrete base 44, and a floor carpet (e.g., carpet tiles) 47 is laid on top of the metal floor plate 46. A power cable 48 is placed in the space formed between the base 44 and the metal floor plate 46. The power cable 48 is undulating and meandering. When the antenna element 11 of the antenna device 1 described above was brought into contact with a part of a person's body on this floor structure, the power received by the antenna device 1 was measured with an oscilloscope and found to be approximately 300mV (pp value) at the power frequency of 50Hz. As can be seen from this experiment, it is clear that a considerable amount of power can be captured by the antenna device 1 from the leakage electric field (quasi-electrostatic field) from the power cables in the room.

[0044] Furthermore, when the power received from the leakage electric field (quasi-electrostatic field) from the power transmission line was measured under the power transmission line, it was found to be approximately 200 mV (pp value). In addition, when a person walks, an electric field is generated, and the antenna device 1 can obtain a voltage waveform as shown in Figure 16. In Figure 16, the vertical axis is voltage (V) and the horizontal axis is time (msec). The electric field generated during walking can be captured as energy by the antenna device 1.

[0045] Using the configuration shown in Figure 2, an experiment was conducted in a windowless laboratory owned by the applicant, connecting the device to a human body to determine how much power could be absorbed. As a result, in the laboratory, enough power (2V) was obtained in one minute to light an LED. In the laboratory with a window, it was possible to obtain 2V of power in 20 seconds. Considering that the embodiment described in Patent Document 1 achieves 100μV in one minute, this represents a 20,000-fold improvement in received power even in a laboratory inside a room.

[0046] According to one embodiment of the technology described above, by bringing an antenna element into contact with the human body, it becomes possible to capture the energy of quasi-electrostatic fields and radio waves generated in space, as well as the electric field generated by the human body when walking. If the captured energy is rectified and stored in a storage element such as a secondary battery, it is possible not only to extend the lifespan of the power supply (battery) of electronic devices worn or used by people, such as portable devices, but also to eliminate the need for charging in some products.

[0047] This technology assumes that the human body is a conductor and normally exists floating above the earth (GND) through insulators such as shoes and socks. This technology is effective in such a state. However, even though the human body is normally floating above the earth, when moving barefoot in places like the sea or a swimming pool, it becomes directly grounded to the earth. Also, when gripping something like a metal handle on a train, the stored electricity may be lost.

[0048] Therefore, as shown in Figure 17, a configuration may be adopted in which the power charge state is constantly monitored or at regular intervals, and the connection with the human body is disconnected when power is about to be lost. Figure 17 shows, for example, a state in which one hand of the human body is in contact with the antenna element 11 and the other hand is touching the grounded metal part 36.

[0049] A switch SW is connected between the antenna section 1a and the rectifier circuit 2. A detector 35 is provided to detect the output of the rectifier circuit 2. The ON / OFF state of the switch SW is controlled by the output of the detector 35.

[0050] Figure 17 shows an example of a full-wave quadrupler rectifier circuit, but a full-wave rectifier circuit configuration as shown in Figure 18 may also be used. The configuration is similar to that of Figure 8 described above, but since a switch SW is connected, there is no need to provide a reverse current prevention diode 65. The same reference numerals are used for the elements corresponding to those in Figure 8, and their descriptions are omitted.

[0051] As shown in Figure 19, in step ST1, it is determined whether a predetermined time has elapsed, and if so, it is determined whether the charging capacity has decreased (step ST2). If it is determined that the charging capacity has decreased, the switch SW is turned OFF (step ST3). Subsequently, if it is determined in step ST4 that a predetermined time has elapsed, the switch SW is turned ON (step ST5). Then, the process returns to step ST1. This configuration makes it possible to prevent the charging capacity from decreasing. Instead of step ST4, it may be possible to detect when the charging capacity has reached a predetermined amount.

[0052] This technology uses the human body as an antenna and creates an electric field using either the ground of the antenna device 1 or a separate conductor, thereby eliminating limitations on the receivable frequency range due to the antenna's shape. Furthermore, by designing the ground of the antenna device 1 or the separate conductor to capacitively couple with the earth's ground, it becomes possible to capture electric field energy from quasi-electrostatic fields other than radio waves. In other words, it enables the conversion of power and noise leaking from power cords and inverters into energy. Thus, by treating the human body as a conductor, it is possible to capture power induced within the human body itself between it and the ground of the antenna device 1.

[0053] For example, as shown in Figures 20A and 20B, the antenna device 1 (shaded area) according to this technology is attached to the operator's wrist (or the back of the hand). The notebook personal computer 71 is equipped with a keyboard 72, and inside the resin case 73 on the back of the keyboard 72 are a circuit board 74 and electronic components 75 such as a processor and switching power supply mounted on the circuit board 74. The electronic components 75 generate spatial noise 76, as indicated by the arrows in Figure 20B.

[0054] The human body (in this case, the wrist) is spatially coupled to the circuit board 74 of the notebook personal computer 71 and the electronic components 75 mounted on the circuit board 74 via the resin keyboard 72. Therefore, when the keyboard 72 is operated, the keyboard 72 and the human body come into contact, and the antenna device 1 receives components of spatial noise 76 emitted from the circuit board 74 and electronic components 75 via the human body. For example, if the antenna device 1 has a full-wave rectifier circuit and a capacitor (e.g., 1.2 μF) is connected after the full-wave rectifier circuit, the terminal voltage of the capacitor rises to 1.2 V in 20 seconds, as shown in Figure 21.

[0055] Next, as an example of an application of the receiving device according to the embodiment, the following electronic devices (power supply devices) are possible. Other possibilities include trackers, monitoring electronic devices, wristband-type healthcare devices, smartwatches, digital watches, wireless headphones, wireless mice, hearing aids, game remote controllers, and ring-type input devices. A tracker is a device that transmits location information acquired via GPS (Global Positioning System) over a telephone network, allowing that location information to be displayed and viewed on a computer, tablet, or smartphone connected to the internet.

[0056] Figure 22 is a block diagram showing an application example of this technology applied to a power supply for an IoT (Internet of Things) for environmental monitoring. It includes an illuminance sensor 51, temperature, humidity, and atmospheric pressure sensors 52, BLE (Bluetooth® Low Energy), and an MCU (Microcontroller unit) 53, and these blocks (ICs) are connected by an I2C bus 54. As the power supply for such an IoT, a power supply circuit based on this technology (configured as an antenna unit 1a and a rectifier circuit 2, as shown in Figure 7 or Figure 8) is applied. When the rectifier circuit 2 is a voltage doubler rectifier circuit, it is important that the diode leakage current during reverse bias is very small. If there is leakage current, a full-wave rectifier circuit is suitable. In terms of diode characteristics, it is good to have one that can supply a large current from a voltage Vf of very small. Furthermore, in order to obtain a high voltage, it is desirable that the leakage current of the reverse voltage application substrate is very small. When using a circuit such as a 4x voltage doubler, the leakage current at this time should be about 0.001 μA when a reverse voltage of 5 V is applied.

[0057] BLE is an extension of Bluetooth®, enabling communication with extremely low power consumption. Using BLE and the MCU 53, detection data from the illuminance sensor 51 and the temperature, humidity, and atmospheric pressure sensors 52 can be wirelessly transmitted to mobile devices such as smartphones and tablets.

[0058] The output terminals 34a and 34b of the rectifier circuit 2 are connected to the DC-DC converter 55. The output of the DC-DC converter 55 charges a secondary battery, such as a lithium-ion secondary battery 56. The output of the lithium-ion secondary battery 56 is supplied to the DC-DC converter 57 and the LDO (Low Dropout) 58.

[0059] The output of the DC-DC converter 57 supplies power to the illuminance sensor 51, temperature, humidity, and atmospheric pressure sensors 52, the BLE, and the MCU 53. Additionally, the output of the LDO 58 supplies power to the BLE and the MCU 53. The LDO is a linear regulator that operates even with a low input / output potential difference. This low potential difference operation minimizes energy loss and allows for a design that suppresses heat generation. The LDO is supplied to the AD conversion inputs of the BLE and the MCU 53, and the output voltage of the secondary battery 56 is monitored by the BLE and the MCU 53.

[0060] The antenna used for external communication such as BLE should preferably be a dipole structure, which does not use the ground of the circuit board and is less susceptible to energy harvesting. By applying the above energy storage circuit, it is also possible to charge the batteries of devices that require charging.

[0061] Furthermore, when used outdoors or in swimming pools, waterproofing, drip-proofing, and weather resistance against ultraviolet rays are required. In the configuration shown in Figure 2, the weather resistance of the antenna device 1 can be improved by coating the surfaces of the antenna element 11 and case 17, or cases 17A, 17B and joint 22 when the case is separated (Figure 2C), with a water-resistant and light-resistant resin.

[0062] As explained with reference to Figures 15 and 16, the voltage induced when a person walks can be obtained by the antenna device 1. As shown in Figure 23, a full-wave rectifier circuit (consisting of diodes 61-64 and Zener diodes 66, 67) is connected to the 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 81. In addition, the output of the full-wave rectifier circuit charges the battery 82 via a reverse current prevention diode 65, and the output of the battery 82 is used as the power source for the voltmeter 81.

[0063] Since voltage is generated by a person's spinal reflex, the voltage fluctuations caused by walking are unique to that individual (known as gait patterns). Therefore, although the output of the voltmeter 81 is not shown in the diagram, it can be analyzed by a computer or other means to perform personal authentication. Furthermore, by learning the voltage fluctuations and information such as the person's physical condition, it is possible to analyze the current information of the person wearing the antenna device 1, such as their physical condition.

[0064] A general configuration for further increasing the output of the antenna device, including the antenna section 1a and the rectifier circuit 2, will be described with reference to Figures 24A and 24B. Figure 24A shows a configuration in which antenna devices 101, 102, and 103 are connected in series. The voltage VL applied to the load RL is (V1 + V2 + V3). Figure 24B 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).

[0065] Figure 25 shows a first embodiment for increasing the output voltage of an antenna device. A first antenna element 11 that comes into contact with the human body is provided, and two second antenna elements 20A and 20B are provided in relation to the first antenna element 11. The antenna elements 20A and 20B are, for example, separate independent circuit boards, housings, etc. A rectifier circuit 2A is provided to rectify the output of the antenna section consisting of antenna elements 11 and 20A, and a rectifier circuit 2B is provided to rectify the output of the antenna section consisting of 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.

[0066] Figure 26 shows the circuit configuration of the first embodiment. This is an example in which 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.

[0067] According to this first embodiment, if an output voltage of, for example, 4V can be obtained with a single antenna device, an output voltage of 8V can be obtained. A larger output voltage can be obtained by connecting two or more rectifier circuits in series. The first embodiment is suitable for cases where the frequency of voltage-inducing power supply noise, etc., is low, as there is no need to consider the distance between antennas.

[0068] The second embodiment, as shown in Figures 27 and 28, provides independent antenna elements 11A and 11B as the first antenna elements that come into contact with the human body. The antenna elements 11A and 11B come into contact with different parts of the human body.

[0069] Figure 28 shows the circuit connection of the second embodiment. This is an example in which 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.

[0070] A third embodiment for increasing the output current of the antenna device is shown in Figures 29 and 30. A first antenna element 11 that comes into contact with the human body is provided, and two second antenna elements 20A and 20B are provided in relation to the first antenna element 11. The antenna elements 20A and 20B are, for example, separate independent circuit boards, housings, etc. A rectifier circuit 2A is provided to rectify the output of the antenna section consisting of antenna elements 11 and 20A, and a rectifier circuit 2B is provided to rectify the output of the antenna section consisting of 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.

[0071] Figure 30 shows the circuit configuration of the third embodiment. This is an example in which full-wave rectifier circuits are used as the parallel-connected rectifier circuits 2A and 2B. Zener diodes 66 and 67 are common elements for the two rectifier circuits 2A and 2B.

[0072] The fourth embodiment, as shown in Figures 31 and 32, provides independent antenna elements 11A and 11B as first antenna elements that come into contact with the human body. Antenna elements 11A and 11B come into contact with different parts of the human body.

[0073] Figure 32 shows the circuit configuration of the fourth embodiment. This is an example in which full-wave rectifier circuits are used as the parallel-connected rectifier circuits 2A and 2B. Zener diodes 66 and 67 are common elements for the two rectifier circuits 2A and 2B.

[0074] In Figures 29, 30, 31, and 32, the antenna elements 11, 11A, and 11B that come into contact with the human body are connected to the connection points of diodes 61a and 64a and diodes 61b and 64b, respectively, in order to ensure they are in phase. Furthermore, the connection points of the full-wave rectifier circuit are the same. The antenna element connected to the metal element is positioned so that the phases of the rectifier circuit are added together in order to ensure that they are in phase.

[0075] Figures 33A, 33B, 34A, and 34B show examples of increasing the number of antennas in this technology. When increasing the number of antennas of the same length, the voltage will decrease slightly, but if you want to increase the current, you can increase the number of antenna elements. As shown in Figures 33A and 34A, the current can be increased by creating and connecting an antenna element 200 at the base of antenna element 20. If you want to increase both the voltage and the current, the length of the antenna elements should be set so that (length of antenna element 20 < length of antenna element 200). Alternatively, as shown in Figures 33B and 34B, 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, on a substrate, housing, rod antenna, etc.

[0076] As mentioned above, if a single antenna device can produce an output current of, for example, 4 μA, it can obtain an output current of 8 μA by connecting them in parallel. Furthermore, if you want to increase the voltage, for example, from a 4V output to an 8V output, this can be achieved by using a series connection. In this way, by combining the above series and parallel circuits, it becomes possible to supply the necessary power to the subsequent stages.

[0077] In the circuit configuration described above, a capacitor is used to smooth the voltage after rectification. It may also be connected in parallel with the Zener diode.

[0078] Although embodiments of this technology have been described in detail above, the technology is not limited to the embodiments described above, and various modifications are possible based on the technical concept of this technology. Furthermore, one or more of the modifications can be arbitrarily selected and combined as appropriate. In addition, the configuration, methods, processes, shapes, materials, and numerical values ​​of the embodiments described above can be combined with each other as long as they do not deviate from the spirit of this technology. For example, this technology can be used in combination with power generation using natural energy, such as solar power generation, or with thermoelectric conversion elements to store energy.

[0079] Furthermore, when the person wearing this antenna device touches someone other than themselves, the surface area of ​​the antenna itself increases, and the amount of received power also increases. In addition, since it is possible to store power continuously, even while sleeping or at other times, it becomes possible to incorporate this receiver into a device such as a Bandlist and charge other batteries directly or via a cable. [Explanation of Symbols]

[0080] 1...Antenna device, 2, 2a, 2b...Rectifier circuit, 4...Energy storage element, 7... Diplexer, 11... First antenna element, 12... Equipment board, 15...Feed point, 19, 20...Second antenna element

Claims

1. It is equipped with a rectifier circuit for receiving the electric field energy of radio waves or quasi-electrostatic fields in space and rectifying the AC signal into DC, The antenna has a first antenna element, which is a conductor used in contact with the human body when the human body is not grounded to the earth, and a second antenna element, which is a conductor separate from the first antenna element and is provided so as not to come into contact with the human body. An antenna device in which, of the AC signals output from the antenna section, the input line output from the first antenna element used in contact with the human body to the rectifier circuit is connected to the rectifier circuit.

2. The antenna device according to claim 1, wherein the contact surface of the first antenna element with the human body is composed of a conductive electrode made of one or a combination of gold, silver, aluminum, copper, iron, nickel, or an alloy, conductive resin, or conductive rubber.

3. The antenna device according to claim 2, wherein the electrode is resin-coated.

4. The antenna device according to claim 2, wherein the electrode is pin-shaped, hemispherical, uneven, or planar, in accordance with the shape of the equipment used.

5. The antenna device according to claim 1, further comprising a separation circuit for frequency-separating the AC signal input from the antenna unit, and a plurality of rectifier circuits for rectifying the AC signals separated by the separation circuit.

6. The antenna device according to claim 1, wherein the second antenna element and the ground are capacitively coupled.

7. The antenna device according to claim 1, which receives an electric field generated when a human body walks.

8. An antenna device according to claim 1, wherein the antenna device is housed in a case, and the contact surfaces of the case with the human body other than the contact parts are made of an insulating material.

9. The antenna device according to claims 1 to 7, wherein the rectifier circuit has a diode for rectification, and the ratio of the forward current when a forward voltage is applied to the reverse current when that voltage is applied in the reverse direction of the diode is at least 4700 times or the resistance value obtained using the reverse current when 10V is applied in the reverse direction of the diode is 1.4 MΩ or more.

10. The antenna device according to claim 9, wherein the diode is made of silicon.

11. The antenna device according to claim 1, further comprising a high-resistance sensor of 2 MΩ or more for measuring the output of the rectifier circuit.

12. The antenna device according to claim 11, wherein the voltage fluctuations of the human body are measured with the high-resistance sensor and analyzed to obtain personal authentication or the state of the human body.

13. An antenna device comprising a plurality of antenna devices according to claim 1, wherein the plurality of antenna devices are connected in series.

14. An antenna device comprising a plurality of antenna devices according to claim 1, wherein the plurality of antenna devices are connected in parallel.

15. The antenna device according to claim 1 comprises a switch inserted between the first antenna element and the rectifier circuit, and a detector that detects the output of the rectifier circuit and controls the ON / OFF state of the switch, A power supply device that turns the switch OFF when the output of the rectifier circuit decreases.

16. The power supply device according to claim 15, which periodically checks the capacity and turns ON / OFF a switch provided on a first antenna element connected to the human body.

17. The antenna device according to any one of claims 1 to 14, A charger to which the output of the rectifier circuit is supplied, A power supply device equipped with an energy storage element connected to the aforementioned charger.

18. The power supply device according to claim 17, further comprising a load that operates using the power stored in the energy storage element.

19. The power supply device according to claim 18, wherein the load comprises at least one of a microcomputer, a wireless communication unit, and a sensor.

20. The antenna device according to any one of claims 1 to 14, A charger to which the output of the rectifier circuit is supplied, An electronic device equipped with an energy storage element connected to the aforementioned charger.

21. The electronic device according to claim 20, comprising a load that operates using the power stored in the energy storage element.

22. The electronic device according to claim 21, wherein the load comprises at least one of a microcomputer, a wireless communication unit, and a sensor.

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