Magnetic wave transmission device, magnetic wave reception device, and magnetic wave communication system

Abstract

To provide at low cost a magnetic wave transmission device, a magnetic wave reception device and a magnetic wave communication system capable of performing magnetic wave communication in the atmosphere, under the ground, in a substance in which a propagation loss of an electromagnetic wave signal is relatively large or in fresh water or in seawater in which a salt concentration of 0% to over 5%.SOLUTION: A magnetic force communication system 101 comprises a transmission device 30 and a reception device 40 for transmitting and receiving magnetic wave signals which are induction-coupled by a fluctuation magnetic field. The transmission device 30 includes at least: a transmission closed loop coil 31 which is in a non-resonant state; power amplification means 34 for supplying an exciting current to the transmission closed loop coil 31 in the non-resonant state; and a bulk capacitor 33 for blocking a DC current flowing to the transmission closed loop coil 31. Both ends of the power amplification means 34 are connected through the bulk capacitor 33 to both ends of the transmission closed loop coil 31, thereby efficiently supplying the exciting current to the transmission closed loop coil 31 in the non-resonant state.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] This invention relates to a magnetic wave transmitting device, a magnetic wave receiving device, and a magnetic wave communication system for performing magnetic wave induction communication over short distances of a few centimeters to medium distances of a few kilometers using an induced magnetic field (hereinafter referred to as magnetic wave signal) based on Faraday's law of electromagnetic induction [∇×E=-∂B / ∂t] in the atmosphere, the earth, in materials where the propagation loss of magnetic wave signals is relatively large (including inside living organisms), or in fresh water or seawater with a salinity of 0% to over 5%. Incidentally, while conventional induction magnetic field communication is called Near Field Communication (NFC) and electromagnetic wave communication is called Far Field Communication (FFC), the magnetic wave communication of the present invention is intermediate between these two and is called Middle Field Communication (MFC). [Background technology]

[0002] The conventional "magnetic wave antenna and magnetic wave communication device" described in Patent Document 1 is described as having the following objective: "To provide, at low cost, a magnetic wave antenna and a magnetic wave communication device using the same that enable magnetic wave communication of any bandwidth, from narrowband to wideband, over short to medium distances of several centimeters to several kilometers using a magnetic wave signal in the atmosphere, in materials where the propagation loss of electromagnetic signals is relatively large, in fresh water or seawater where the salinity exceeds 0% to 5%, or in an induction path that is a combination of these. The magnetic wave antenna is brought into a non-resonant state close to a resonant state using a magnetic wave signal that is inductively coupled by a fluctuating magnetic field, in the induction path and over short to medium distances, in order to suppress significant mismatches of the magnetic wave antenna caused by the radiation or re-radiation of the displacement current."

[0003] Furthermore, the conventional "positioning device and system using magnetic wave signals" described in Patent Document 2 is described as having the following characteristics: "The purpose of the positioning device and system is to measure distance, direction, or both by using a magnetic wave signal inductively coupled by a fluctuating magnetic field in the atmosphere, in a material in which the propagation loss of an electromagnetic wave signal is large compared to the propagation loss in the atmosphere, in fresh water or seawater with a salinity of 0% to more than 5%, in a closed environment such as indoors, or in an induction path that is a combination of these, and the magnetic wave antenna is placed in a non-resonant state close to a resonant state by using a magnetic wave signal inductively coupled by a fluctuating magnetic field in the induction path and over short to medium distances in order to suppress significant mismatches of the magnetic wave antenna caused by radiation or re-radiation of the displacement current."

[0004] Furthermore, the conventional "variable magnetic field signal receiving device using an MI element" described in Patent Document 3 is described as "relating to a variable magnetic field signal receiving device using an MI (Magneto-Impedance) element for performing variable magnetic field communication using a variable magnetic field signal over a short distance of a few centimeters to a medium distance of a few kilometers in the atmosphere, in a material in which the propagation loss of the electromagnetic wave signal is relatively large, in fresh water or seawater with a salinity of 0% to more than 5%, or in an induction path that is a combination of these."

[0005] However, according to Patent Documents 1 to 3, the transmitting coil and receiving coil are in a non-resonant state close to a resonant state, and the technical scope that should be specified by the description of a "non-resonant state close to a resonant state" is unclear. As a result, problems such as a sudden increase in propagation loss due to radiation of electromagnetic waves from the transmitting antenna or re-radiation of electromagnetic waves from the receiving antenna when the propagation distance increases remain unresolved. According to the present application, in order to limit the flow of current to only excitation current in the transmitting coil, the output resistance of the AC power supply is made lower than the impedance of the transmitting coil, thereby ensuring that the transmitting coil is in a non-resonant state, suppressing the radiation of electromagnetic wave signals and efficiently radiating high-purity magnetic wave signals, and furthermore, by taking similar measures for the receiving coil, it becomes possible to transmit and receive magnetic wave signals with high sensitivity. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] WO / 2015 / 087724 [Patent Document 2] Patent Publication 2016-180615 [Patent Document 3] Patent Publication No. 2017-034488 Summary of the Invention [Problem to be solved by the invention]

[0007] This invention has been made to solve the above-mentioned problems, and has an object to provide an inexpensive magnetic wave transmitting device, a magnetic wave receiving device, and a magnetic wave communication system for providing power to other moving bodies, detecting the position of moving bodies or persons in distress, detecting obstacles, exploring for mineral resources, or achieving a combination of these, by performing contactless power supply, magnetic wave communication, information exchange, data exchange, and highly accurate measurement of direction and / or distance in the atmosphere, the earth, in materials where the propagation loss of electromagnetic wave signals is relatively large (including inside living bodies), in fresh water or seawater where the salinity exceeds 0% to 5%, or in a propagation path of a magnetic wave signal that is a combination of these. [Means for solving the problem]

[0008] The magnetic wave transmitting device and magnetic wave receiving device of this invention are a transmitting device and a receiving device for transmitting and receiving a magnetic wave signal that is inductively coupled by a fluctuating magnetic field in the atmosphere, the earth, in materials (including inside living bodies) where electromagnetic waves are highly attenuated, or in fresh water or seawater with a salinity concentration of 0% to 5%, and the transmitting device is equipped with at least a transmitting closed loop coil in a non-resonant state, an AC power source for supplying an excitation current to the transmitting closed loop coil in the non-resonant state, and a large-capacity capacitor for blocking DC current flowing through the transmitting closed loop coil, and both ends of the AC power source are connected to both ends of the transmitting closed loop coil via the large-capacity capacitor, and the excitation current is efficiently supplied to the transmitting closed loop coil in the non-resonant state.

[0009] In addition, the transmitting coil is composed of a closed loop coil and is configured around a core of high magnetic permeability such as a ferrite core or an amorphous core, and the output impedance when the AC power supply is conductive is set to a value that is sufficiently low compared with the impedance of the transmitting closed loop coil in the non-resonant state, so as to reliably put the transmitting closed loop coil into a non-resonant state. The AC power input stage also generates a pulse width modulated square wave signal, which is given a unique identifier and a digital signal for detecting or probing direction and / or distance. In addition, the output stage of the AC power supply is composed of SiC-MOSFET, or has low output resistance, or has an equivalent device structure, and a half-bridge inverter or a full-bridge inverter is configured to amplify the signal, thereby providing an effect of being able to supply a large amount of excitation current to the transmission coil in the non-resonant state.

[0010] Furthermore, in the configuration of the transmitting device, when the angular frequency of the excitation current supplied from the AC power supply is ω, the inductive reactance of the transmitting coil is ωL0, the impedance of the DC current blocking capacitor connected in series with the output of the AC power supply is close to 0Ω, and the output resistance of the AC power supply is R0, by making R0<<ωL0, the voltage across both ends of the transmitting closed loop coil ≒ the output voltage of the AC power supply, a non-resonant state is reached, the radiation of the electromagnetic wave signal is suppressed, and the magnetic wave signal can be efficiently radiated. This has been confirmed both theoretically and experimentally.

[0011] Meanwhile, in the receiving device, the magnetic wave signal radiated from the magnetic wave transmitting device is inductively coupled to a receiving closed loop coil in a non-resonant state, to a magnetic impedance effect element, or to a magnetic resistance element, and the output signal is amplified by a high-gain amplifier and output, or mixed with a receiving station signal, converted to an intermediate frequency signal and amplified, and / or demodulated to a pulse-width modulated digital signal and output.

[0012] Also, by measuring the output level (RSSI) of the directly amplified signal or the intermediate frequency signal, a distance detection function from the transmitting device can be added. In addition, contactless power supply is possible by inductively coupling a receiving closed loop coil in close proximity to the induction magnetic field radiated from the transmitting closed loop coil and rectifying the output to convert it into DC power.

[0013] In addition, the receiving device can be provided with multiple sets of induced magnetic field detection elements, which are a combination of the non-resonant closed loop coil, magnetic impedance effect element, or magnetic resistance element, arranged at intervals, and can be given a detection function for measuring the output level, timing, and / or phase of the multiple sets of output signals and detecting the direction and / or distance with high accuracy. In addition, the multiple sets of closed loop coils and / or multiple sets of magnetic impedance effect elements or magnetic resistance elements, and a detection device for detecting the direction and / or distance, can be carried by or equipped on a mobile body.

[0014] The magnetic wave transmitting device and the magnetic wave receiving device constitute a magnetic wave communication system. Also, the magnetic wave transmitting device is carried by or attached to a first moving body, and the magnetic wave receiving device is carried by or attached to a second moving body. Furthermore, the magnetic wave transmitting device and / or the magnetic wave receiving device are carried by a moving body or attached to the moving body.

[0015] The magnetic wave transmitting device and / or magnetic wave receiving device can also be used to detect or locate conductive and / or reflective objects, including explosives, with high accuracy to determine their location, orientation, and / or size. Furthermore, the conductive object and / or reflective object may be carried by or attached to a moving object, thereby enabling the moving object to be searched for and detected. In addition, the mobile body carrying the magnetic wave transmitting device may have a distress detection sensor for detecting a distress state, and upon detection of distress, the magnetic wave transmitting device may be started or stopped. Effect of the Invention

[0016] Traditionally, sound waves or ultrasound have been used exclusively for wireless communication in seawater, but in recent years, wireless communication in the deep sea using light waves has been put to practical use. However, electromagnetic waves have a propagation loss of 100 dB / m in the 1 MHz band, and at extremely low frequencies below a few tens of kHz, problems exist in that it can only be used for one-way wireless communication from land, requiring the installation of large antenna equipment on land. In addition, sound waves or ultrasonic waves have a slow propagation speed in seawater of 300 to 1000 m / sec, making rapid mutual communication difficult and susceptible to the effects of echoes or reflections from the sea surface.

[0017] The magnetic wave transmitting device, magnetic wave receiving device, and magnetic wave communication system of the present invention enable short- to medium-distance wireless communication in the atmosphere, the earth, in materials where electromagnetic waves are highly attenuated (including inside living organisms), or in fresh water or seawater with a salinity of 0% to 5%, and the propagation speed is 300 km / sec, which is similar to the propagation speed of magnetic storms radiated from the sun, which is 1 / 1000 of electromagnetic waves and 1 / 1000 of ultrasonic waves, and direction and / or distance can be measured with high accuracy, making it possible to detect the position of moving objects, detect obstacles, explore mineral resources, explore missing persons, or a combination of these at low cost. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a block diagram of a magnetic wave communication system 101 according to a first embodiment of the present invention. [Diagram 2] FIG. 1 is a configuration diagram of a magnetic wave transmission device according to a second embodiment of the present invention. [Diagram 3] FIG. 13 is a configuration diagram of a magnetic wave receiving device according to a third embodiment of the present invention. [Figure 4] FIG. 11 is a block diagram of a magnetic wave receiving device according to a fourth embodiment of the present invention. [Diagram 5] FIG. 13 is a configuration diagram of a magnetic wave communication system 102 according to a fifth embodiment of the present invention. [Figure 6] FIG. 13 is a block diagram of a magnetic wave communication system 103 according to a sixth embodiment of the present invention. [Figure 7] FIG. 13 is a block diagram of a magnetic wave communication system 104 according to a seventh embodiment of the present invention. [Figure 8](a) Measurement data of the propagation characteristics in seawater using the non-resonant closed loop coil of the present invention. (b) Example of the characteristics of the magnetoresistance element used in the present invention. (c) Simulation results of the propagation characteristics in seawater of the magnetic wave signal of the present invention. (d) Configuration diagram of the direction finding signal of the present invention. (e) Measurement data of the propagation speed of the magnetic wave signal of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. EXAMPLES

[0020] FIG. 1 is a configuration diagram of a magnetic wave communication system 101 in a first embodiment of the present invention, in which 30 is a transmitting device, 31 is a transmitting coil, 32a and 32b are connection terminals of the transmitting coil, 33 is a DC blocking capacitor, 34 is a power amplifying means, 35 is a pulse width modulating means, 36 is a digital signal generating means, 40 is a receiving device, 41 is a high permeability core, 42 is a receiving coil, 43 is a DC blocking capacitor, 44 is a buffer amplifying means, 45 is a filter, 46 is a low frequency amplifier, 47 is an output terminal, 101 is a magnetic wave communication system A, and 200 is an induced magnetic field signal (hereinafter referred to as a magnetic wave signal). Here, a digitally modulated excitation current is supplied to the transmitting coil 31 via a DC blocking capacitor 33 by a power amplifier means 34, a pulse width modulation means 35, and a digital signal generating means 36, and a digitally modulated magnetic wave signal is efficiently radiated toward the outside of the transmitting coil.

[0021] However, if electromagnetic waves are present in addition to the magnetic wave signal radiated from the transmitting coil, large propagation losses occur in the propagation path, such as in seawater. Therefore, it is essential that the output resistance of the power amplifying means 24 is low, and is less than one-tenth the impedance of the transmitting coil (for example, less than 1 Ω), so that the transmitting coil can be placed in a non-resonant state and excitation current can be supplied efficiently.

[0022] On the other hand, the magnetic wave signal 200 radiated from the transmitting coil 31 is inductively coupled to the receiving coil 42 based on Faraday's law of electromagnetic induction [∇×E=-∂B / ∂t], and the induced electromotive force is input to the low-frequency amplifier 43 via the DC blocking capacitor 43. Here, when the receiving coil 42, the DC blocking capacitor 43, and the buffer amplifier 44 are in a series or parallel resonant state, the magnetic wave signal becomes an electromagnetic wave and is re-radiated to the outside. Therefore, by adopting a high impedance input amplifier such as a source follower circuit for the low-frequency amplifier 44, the receiving coil 42 is put into a non-resonant state, and the re-radiation of the electromagnetic wave can be suppressed. In addition, the excitation current supplied to the transmission coil lags behind the applied voltage by 90° and becomes reactive power, so that only the resistance loss of the coil becomes the actual loss except during non-contact power supply.

[0023] On the other hand, the induced magnetic field 200 emitted from the transmitting coil 31 propagates through the atmosphere, the earth, substances that have a large attenuation of radio waves (including inside living bodies), or through fresh water or seawater with a salinity of 0% to 5%. If the receiving coil is a closed loop coil with multiple turns and is installed on a moving body horizontally facing the transmitting coil, and the voltage of the AC power supply 31 connected to the transmitting coil is Ein×Sin(ωt), then based on Faraday's law of electromagnetic induction [∇×E=-∂B / ∂t], the electromotive force Eout induced in the receiving coil is given by Eout=-dΦ / dt=[(Ein / 10)×((N2 / N1)×S2) / (D1^3)]Sin(ωt) - - -(1) This indicates that the amplitude of the above formula is independent of the frequency of the AC power supply and is therefore broadband.

[0024] Here, N1=the number of turns in the transmitting coil, N2=the number of turns in the receiving coil, S2=the area of ​​the receiving coil, and D1=the distance between the transmitting coil and the receiving coil. Also, according to the above formula (1), the electromotive force induced in the receiving coil increases in proportion to the voltage of the AC power supply, increases in proportion to the number of turns N2 and the area S2 of the receiving coil, and as shown in Fig. 7(a), decreases in inverse proportion to the cube of the distance D1 between the transmitting coil and the receiving coil, decreasing at 16 dB / oct, and decreasing by 60 dB when the distance becomes 10 times, and increases in inverse proportion to the number of turns of the transmitting coil, which is consistent with the experimental results.

[0025] In addition, the radiated induction magnetic field 200 is magnetically collected by the high-permeability core 41 of the receiving device 40, inductively coupled to the receiving coil 42 in a non-resonant state to generate an electromotive force. The electromotive force is connected to the buffer amplifier 44 of the source follower circuit via the DC blocking capacitor 43. After impedance conversion, the noise component including the harmonic component is removed by the filter 45, amplified by the low-frequency amplifier 46, output from the output terminal 47, and demodulated into a digital signal by the subsequent detection and amplifier. Also, when a closed-loop coil is used for the receiving coil, in order to improve the receiving sensitivity, it is necessary to use a large-sized high-permeability core, which is large and heavy. Therefore, either step-up with a transmission line transformer or, as described later, by using the magnetoresistive element (MI element), miniaturization and weight reduction can be achieved.

[0026] In addition, in the above configuration, when the angular frequency of the electromotive force induced in the receiving coil 42 is ω, the inductive reactance of the receiving coil 42 is ωL2, and since the DC blocking capacitor 43 connected to the receiving coil has a low impedance, when the input resistance of the buffer amplification means 44 is R2, from (ωL2) << R2, the receiving coil 42 is in a non-resonant state, suppressing the re-radiation of electromagnetic waves and increasing losses, and the magnetic wave signal can be efficiently received. For example, when the distance between the transmitting coil and the receiving coil is set to 0.5 m to 10 m and the distance is relatively short, the measurement data of the propagation loss of the magnetic wave signal in seawater is as shown in Figure 7(a). Although the propagation loss attenuates as the cube of the distance, this is compared to the 100 dB attenuation over 1 m when the electromagnetic wave is 1 MHz, which indicates that long-span contactless power supply is possible.

[0027] Therefore, when the receiving coil is located within 1 m of the transmitting coil, when the receiving coil is inductively coupled to the induced magnetic field emitted from the transmitting coil, the electromotive force induced in the receiving coil becomes large. Therefore, by converting the output to a DC voltage using a full-wave rectifier means with an extremely low input impedance instead of the buffer amplifier 46, the receiving coil becomes non-resonant, and contactless power supply becomes possible in the atmosphere, the ground, in materials where electromagnetic waves are highly attenuated, or in fresh water or seawater with a salinity of 0% to over 5%. EXAMPLES

[0028] FIG. 2 is another configuration diagram of a magnetic wave transmission device in Example 2 of the present invention, in which 32a and 32b are connection terminals of a transmission coil, 33 is a DC blocking capacitor, 34a is a transmission line transformer, 34b is a power amplifier, 35 is a pulse width modulation means, 36a is a clock signal generation means, and 36b is a digital signal generation means. Here, a step-up transformer with a turns ratio of 1:2 is shown as an example of the transmission-line transformer 34a, and a half-bridge inverter using two sets of switching elements is shown as an example of the power amplifying means 34b. For example, FIG. 7(a) shows measurement data of the propagation characteristics in seawater when a non-resonant closed loop coil is driven by a low-voltage inverter.

[0029] Furthermore, by configuring a half-bridge inverter or a full-bridge inverter in the output stage of the power amplifier means 34b, which is an SiC-MOSFET having a resistance value of 1 Ω or less when conductive, or has equivalent material characteristics, or has an equivalent device structure, and amplifying the signal to a high voltage, and supplying an excitation current to the non-resonant transmitting coil, according to a simulation result when driven at the high voltage, as shown in FIG. 7c, magnetic wave wireless communication over a long distance of more than 700 m in seawater is possible. In addition, by inputting the output of the triangular waveform clock signal generator 36a and the output of the transmission signal generating means 37 to the pulse width modulation means 36, a rectangular wave signal having a pulse width according to the input voltage of the transmission signal generating means 37 is input to the power amplifying means 34b. Furthermore, by adding a transmission line transformer 34a to the power amplifying means 34b, the output power can be boosted to an integral multiple of the power supply voltage. EXAMPLES

[0030] FIG. 3 is another configuration diagram of a magnetic wave receiving device in the third embodiment of the present invention, in which 50 is a receiving device, 51 is a local signal oscillator, 52 is a magnetic resistance element, 53 is a magnetic flux collecting element, 54 is a detection coil (receiving coil), 55 is a DC blocking capacitor, 56 is a buffer amplifier, 57 is a filter, 58 is an intermediate amplifier, 59 is a detection amplifier, and 200 is an induced magnetic field.

[0031] When a local oscillator signal is supplied to the magnetoresistance element 52, the impedance across both ends of the magnetoresistance element (MI element) changes in accordance with a second-order distortion curve as shown in FIG. 7(b), and therefore the frequency of the received local oscillator signal and the frequency of the magnetic wave signal are mixed and output to the detection coil 54 as a baseband signal or an intermediate frequency signal. The local signal is a continuous signal of a constant frequency, and the signal level is adjusted so that the magnetoresistive element operates within the region of secondary distortion.

[0032] Furthermore, if the local oscillator signal is represented as ASin(ω1t+φ1) and the magnetic wave signal is represented as BSin(ω2t+φ2), then [ASin(ω1t+φ1)+BSin(ω2t+φ2)]2 =[ASin(ω1t+φ1)]2+2AB[(Sin(ω1t+φ1))×(Sin(ω2t+φ2))]+[BSin(ω2t+φ2)]2 =[A2Sin(2ω1t+2φ1)]+AB[Cos(ω1t-ω2t+φ1-φ2)+Cos(ω1t+ω2t+φ1+φ2)]+[B2Sin(2ω2t+2φ2)] - - - (2) It becomes.

[0033] Therefore, from equation (2), when AB[Cos(ω1t-ω2t+φ1-φ2) is output from detection coil 54 as an intermediate frequency signal, amplified by buffer amplifier means 55, and selected by filter 56, an example of the characteristics of the magnetoresistance element (MI element) is shown in Figure 7(b), where the voltage (mV) output from the magnetoresistance element exhibits a square characteristic with respect to the strength (mT) of the magnetic field inductively coupled to magnetoresistance element 52, and when the strength of the inductively coupled magnetic field changes between ±0 and ±0.2 (mT), an output voltage of ±4V=±132dBμV is output from coupling coil 53, and the magnetoresistance element 52 operates as a mixer.

[0034] In addition, when the magnetic wave signal propagates through the guidance path, as shown in FIG. 7(a) in the atmosphere and / or seawater, the magnetic wave signal attenuates by 60 dB when the distance increases by 10 times, and the level fluctuation is large, so that the intermediate frequency amplifier must be provided with an AGC (automatic gain control) and / or an amplitude limiting means. For example, if the magnetic field strength at a point 1 m away from the position of the transmitting coil is 0.2 mT and the output voltage from the coupling coil 54 is 132 dBμV, the output voltage at a point 100 m away will be 12 dBμV, meaning that a magnetic wave signal can be received.

[0035] Also, when using the magnetic wave signal, when the distance between the transmitting device and the receiving device becomes 10 times, the signal level attenuates by 60 dB and the level fluctuation is large. Therefore, when using the level fluctuation for distance measurement, a merit can be obtained that the measurement error can be improved to 1 / 3 or less compared to the case of using electromagnetic waves.

[0036] Also, in the above configuration, when the angular frequency of the electromotive force induced in the detection coil 54 is ω, the inductive reactance of the detection coil is ωL2, the DC current blocking capacitor 55 connected in series with the detection coil, and the input resistance of the buffer amplification means 56 is R2, from (ωL2 << R2), the detection coil 54 becomes non-resonant, suppresses the re-radiation of electromagnetic waves, and can efficiently receive the magnetic wave signal.

Example

[0037] FIG. 4 is another configuration diagram of the magnetic wave receiving device in Embodiment 4 of the present invention, 50 is a receiving device, 51a is a local signal oscillator, 51b is a π / 2 phase shift means, 52a and 52b are magnetoresistive elements, 53a and 53b are magnetic flux concentrating elements, 54a and 54 are detection coils, 55a and 55b are DC current blocking capacitors, 56a and 56b are buffer amplification means, 57a and 57b are filters, 58a and 58b are intermediate amplification means, and 59a and 59b are quadrature detection means, and 200 is an induced magnetic field.

[0038] Here, the output of the local oscillator 51a is branched into the magnetoresistive element 52a and the magnetoresistive element 52b via the π / 2 phase shifter 51b, and supplies a continuous high-frequency signal of a certain frequency or a high-frequency signal whose frequency is swept. The magnetoresistive elements 52a and 52b are mixed with an induced magnetic field that is magnetically collected and inductively coupled by the external magnetic collection elements 53a and 53b, and an intermediate-frequency signal of the difference between the frequency of the received local oscillator signal and the frequency of the magnetic force wave signal is output from the detection coils 54a and 54b. When input to the buffer amplification means 56a and 56b (input resistance = R2) via a DC blocking capacitor connected in series with the detection coil, since (ωL2) << R2, the reception coils 54a and 54b are both non-resonant, suppressing the re-radiation of electromagnetic waves and increasing losses, and enabling efficient reception of the magnetic force wave signal.

[0039] Furthermore, the intermediate-frequency signal output from the detection coil 54a is buffer-amplified by the buffer amplification means 56a, the frequency band is selected by the filter 57a, amplified and detected by the intermediate-frequency amplification means 58a and the quadrature detection means 59a, and output as an "I signal". On the other hand, it is impedance-converted by the buffer amplification means 56b, the frequency band is selected by the filter 57b, amplified and detected by the intermediate-frequency amplification means 58b and the quadrature detection means 59b, and output as a "Q signal". The IQ signals contain accurate phase information and play an important role in the direction detection system of the present invention.

Example

[0040] FIG. 5 is a configuration diagram of a magnetic wave communication system 102 in a fifth embodiment of the present invention, in which 30 indicates a magnetic wave transmitting device, 50a and 50b indicate magnetic wave transmitting and receiving antennas, 60 indicates a direction finding device, 81 indicates the distance between the magnetic wave transmitting and receiving antennas 50a and 50b, 82 indicates the directivity of the direction finding device, 83 indicates the distance between the magnetic wave transmitting antenna and the magnetic wave receiving antenna, 84 indicates the deviation between the directivity of the direction finding device and the direction of the magnetic wave transmitting antenna, 85 indicates the difference in distance from the magnetic wave transmitting antenna to the magnetic wave receiving antennas 50a and 50b, 86 indicates the direction in which the magnetic wave transmitting device is located, and 102 indicates a magnetic wave communication system B.

[0041] Here, a digital signal consisting of a synchronization signal (Start Frame Delimiter) 61, a MAC (Medium Access Control) layer 62, and a direction finding measurement signal 63, as shown in FIG. 7(d), is transmitted intermittently at intervals of several to several tens of seconds from the magnetic wave transmitting device 30. The synchronization signal 61 is a multi-bit unique word for roughly matching the control timing between the magnetic wave transmitting device and the magnetic wave receiving device. The MAC layer 62 is an identification number of the magnetic wave transmitting device, a destination number, additional information, or a combination of these. The direction measurement signal 63 is for measuring with high accuracy the direction in which the magnetic wave transmitting device is located.

[0042] Also, as shown in Figure 7(e), a 440 kHz square wave signal is supplied from a magnetic wave transmitter 91 to a transmitting coil 92 to radiate a magnetic wave signal, the square wave signal is received by a receiving coil 93 and amplified by a buffer amplifier 94, the delay time (μs) from the time of transmission to the time of reception is measured by a logic analyzer 95, and the speed (km / s) at which the magnetic wave signal propagates through the atmosphere is calculated from the distance (cm) between the transmitting coil and the receiving coil.

[0043] As shown in the measurement results, the propagation speed of the magnetic wave signal was calculated to be approximately 305 km / s. This value is the same as the propagation speed of a magnetic storm emitted from the sun, is 1 / 1000 of the propagation speed of an electromagnetic wave, and is 1000 times faster than an ultrasonic wave. Therefore, it is an intermediate speed between that of an electromagnetic wave and an ultrasonic wave, making it possible to measure direction and / or distance with high accuracy. Furthermore, while the error in distance measurement when using electromagnetic wave signals was approximately 14 m, when magnetic wave signals are used the error is reduced to 1 / 1000, making it possible to measure distance with an error of approximately 1.4 cm. Alternatively, if the measurement accuracy of the propagation time between two points is the same when using electromagnetic wave signals and when using magnetic wave signals, the distance measurement error is improved to 1 / 1000 when using magnetic wave signals, resulting in higher accuracy due to the slower propagation speed.

[0044] From the above measurement results, it is found that the wavelength of a 2 MHz magnetic wave signal is approximately the same as that of a 2 GHz electromagnetic wave, and by using a 2 MHz magnetic wave signal, it is possible to detect distance and / or direction with high accuracy. Meanwhile, the output signals of the magnetic wave receiving antennas 50a and 50b are alternately connected to a direction finding device 60, which waits for a synchronization signal 61 and a MAC layer 62 transmitted from the magnetic wave transmitting device 30. If the received signal is a direction finding request signal, the output signals of the magnetic wave receiving antennas 50a and 50b are immediately switched while measuring the phase difference of the direction measurement signal 63.

[0045] For example, if the deviation of the magnetic wave transmitter from the directivity of the direction finder is α°, then α°=arcTan(D / L)=arcTan(ΔL / L) - - -(3) It becomes. Here, L(m) = distance 83 between the magnetic wave transmitting device and the magnetic wave receiving device, D(m) = deviation 84 between the directivity of the direction finding device and the direction of the magnetic wave transmitting device, and ΔL(m) = difference in distance 85 from the magnetic wave transmitting device to the magnetic wave receiving antennas 50a and 50b.

[0046] Alternatively, the output signals of the magnetic wave receiving antennas 50a and 50b are alternately or sequentially switched, and the phase difference before and after the switching is measured while the direction measurement signal 63 continues, and the result is (φA-φB); If (-90°<α°<+90°), then α°=arcSin(φA-φB) - - -(4) Thus, the deviation α° of the magnetic wave transmitter from the directivity of the direction finder can be measured with an accuracy of ±0.5°.

[0047] Furthermore, by providing a magnetic collecting element 53 in front of the magnetic resistance element 52, the directivity of the magnetic resistance element (particularly, the front-to-rear ratio) can be improved, thereby further improving the measurement accuracy of the direction in which the magnetic wave transmitting device is located. The magnetic wave transmitting device also has a distress detection sensor for detecting water pressure fluctuations, temperature fluctuations, acceleration fluctuations, avalanches, landslides, seawater reactions, cessation of biological reactions, when a mobile phone does not receive a control channel, emergency activation, and the like, or a combination of these, and intermittently transmits, activates, and / or stops a distress signal including the direction measurement signal 61.

[0048] The above explanation has been about using a single moving body to measure the direction and / or distance to which a magnetic wave transmission device is located, but it is also possible to measure distance in addition to direction by placing multiple moving bodies at intervals, or by moving a single moving body at intervals while measuring the direction to which the magnetic wave transmission device is located. Alternatively, it is possible to measure the distance by equipping a magnetic wave transmitting device and a magnetic wave receiving device on a first mobile body, and equipping a different magnetic wave transmitting device and a magnetic wave receiving device on a second mobile body, and communicating between them.

[0049] In addition, since it is possible to measure direction in the atmosphere, underground, in materials where the propagation loss of electromagnetic waves is relatively large, and in fresh water or seawater with a salinity of 0% to 5%, it can be used to search for meeting people, wanderers, victims of avalanches, victims of cliff collapses caused by floods or earthquakes, etc., and especially victims of drowning in seawater. The present invention can also be applied to RFID tags used for individual management or ecological surveys of fish in seawater, biotelemetry, and the like.

[0050] Furthermore, if the victim is wearing a conductive material and / or a reflective object on his / her clothing or cold weather gear, the magnetic wave transmitting device and the magnetic wave receiving device can be used to search for the victim with high accuracy. Furthermore, by equipping a mobile phone with the magnetic wave transmitting device and / or the magnetic wave receiving device, it can be used for everyday purposes other than when lost, such as searching for a meeting person, searching for a place to visit, or searching for an exhibit. In addition, the level, timing, and / or phase of the intermediate frequency signal from the magnetic wave receiving device can be measured to detect the direction and / or distance from which the received magnetic wave signal has arrived. EXAMPLES

[0051] FIG. 6 is a configuration diagram of a magnetic wave communication system 103 in Example 6 of the present invention, in which 91 is an output stage of a magnetic wave transmission device, 92 and 93 are DC blocking capacitors, 94 is a non-resonant transmitting closed loop coil, 95 is a non-resonant receiving closed loop coil, 96 is a DC blocking capacitor, 97 is a full-wave rectifier circuit, and 98 is a storage battery. Here, the output stage 91 of the magnetic wave transmission device has a low resistance of 1 Ω or less when conducting, and is, for example, a half-bridge or full-bridge DC / AC inverter using SiC trench MOSFETs, and supplies excitation current to a non-resonant transmission closed loop coil 94 via DC blocking capacitors 92, 93, and radiates an induced magnetic field to the outside.

[0052] An electromotive force is induced in the receiving closed loop coil 95, which is non-resonant and located close to the transmitting closed loop coil 94, according to Faraday's law. This electromotive force is connected to a rectifier circuit 97 via a DC blocking capacitor 96 and converted into a DC voltage, which can rapidly charge a storage battery 98, such as an electric double layer capacitor. Since both the transmitting closed loop coil and the receiving closed loop coil are non-resonant, non-contact power supply in seawater is possible. EXAMPLES

[0053] The basic configuration of remote exploration using drones that dive underwater is shown in Figure 7. Submersible drones 1 and 2 are each equipped with a wireless power supply device (WPT), a magnetic wave communication device (UWT), and a propulsion system (PCS), and they communicate with each other, and the distance between them is measured with high accuracy by communication between the magnetic wave communications (UWT), and it is possible to supply power between them and send and receive information as necessary. [Industrial Applicability]

[0054] Because the present invention is configured as described above, the magnetic wave transmitting device and / or magnetic wave receiving device can be mounted on self-propelled means, flying means, drilling means, or submersible means in the atmosphere, underground, fresh water, seawater, or on a guided path that is a combination of these, and can be used in a wide range of applications, such as short-range contactless power supply, short- to medium-range communication systems, ship collision prevention systems, marine resource exploration systems, biotelemetry, sensing networks, inter-personal voice communication devices for divers, RFID tag devices, communication, remote control, and docking control with flying boats, submarines, or underwater robots, detection devices for shipwrecked or stranded persons, depth sounders, seabed resource exploration devices, metal detectors, or communication between EVs and contactless power supply devices. [Explanation of symbols]

[0055] 30 Magnetic wave transmitter 31 Transmitting closed loop coil 32a, 32b Transmission closed loop coil connection terminals 33 DC blocking capacitor 34 Power Amplification Means 35 Pulse Width Modulation Means 36 Signal generation means

[0056] 40 Receiving device 41 High permeability core 42 Receiving closed loop coil 43 DC blocking capacitor 44 Buffer Amplification Means 45 Filter 46 Low Frequency Amplifier 47 Output Connector

[0057] 50 Magnetic wave receiving device 50a, 50b Receiving antenna 51, 51a Local signal oscillator 51b π / 2 phase shift means 52, 52a, 52b Magnetic impedance element or magnetic resistance element 53, 53a, 53b magnetic collecting element 54, 54a, 54b Detector coil 55, 55a, 55b DC blocking capacitors 56, 56a, 56b Buffer amplifier means 57, 57a, 57b Filters 58, 58a, 58b Intermediate frequency amplifier 59, 59a, 59b Detector amplifier

[0058] 60 direction finding device 61 Synchronization signal 62 MAC Layer 63 direction finding signal 81 Receiving antenna spacing 82 Directional Characteristics of Direction Finding Devices 83 Distance between magnetic wave receiving antenna and magnetic wave transmitting antenna 84 Deviation from direction finding device directionality 85 Distance difference between magnetic wave receiving antenna and magnetic wave transmitting antenna 86 Angle from the direction-finding device's directivity

[0059] 91 DC / AC inverter 92, 93 DC blocking capacitor 94 Transmitting closed loop coil 95 Receiving closed loop coil 96 DC Blocking Capacitor 97 AC / DC Converters 98 Quick Battery

Claims

1. A transmitting device for transmitting a magnetic wave signal that is inductively coupled by a fluctuating magnetic field in the atmosphere, the earth, a substance in which electromagnetic waves are significantly attenuated (including inside a living body), or in fresh water or seawater with a salinity of 0% to more than 5%, A transmitting coil; an AC power source for supplying an excitation current to the transmission coil; a large-capacity capacitor for blocking a direct current flowing through the transmission coil; connecting both ends of the AC power supply to both ends of the transmission coil via the large-capacity capacitor; The transmission coil is placed in a non-resonant state and the excitation current is supplied.

1. A magnetic wave transmitting device comprising:

2. The transmitting coil is constituted by a closed loop coil.

2. A magnetic wave transmitting device according to claim 1.

3. The transmitter coil may be air-core or may be constructed around a core of high magnetic permeability.

3. A magnetic wave transmitting device according to claim 1, wherein the magnetic wave transmitting device is a magnetic wave transmitting device.

4. The output impedance of the AC power supply when energized is smaller than the impedance of the transmission coil, and the transmission coil is placed in a non-resonant state.

4. A magnetic wave transmitting device according to claim 1, wherein the magnetic wave transmitting device is a magnetic wave transmitting device.

5. The output stage of the AC power supply is a SiC-MOSFET, or has a low resistance saturation characteristic, or has an equivalent device structure, constitutes a half-bridge inverter or a full-bridge inverter, and supplies an excitation current to the transmission coil in the non-resonant state.

5. A magnetic wave transmitting device according to claim 1, wherein the magnetic wave transmitting device is a magnetic wave transmitting device.

6. The AC power supply has a digital modulation means and outputs a pulse-width modulated rectangular wave signal.

6. A magnetic wave transmitting device according to claim 1, wherein the magnetic wave transmitting device is a magnetic wave transmitting device.

7. The AC power supply has a transmission line transformer and boosts the output voltage.

7. A magnetic wave transmitting device according to claim 1, wherein the magnetic wave transmitting device is a magnetic wave transmitting device.

8. The digital modulation means provides a unique identification code for direction and / or distance detection.

8. A magnetic wave transmitting device according to claim 1, wherein the magnetic wave transmitting device is a magnetic wave transmitting device.

9. The magnetic wave signal transmitted from the magnetic wave transmitter according to any one of claims 1 to 8 is received by inductively coupling it to a closed loop coil and / or a magneto-impedance effect element or a magneto-resistance element. A magnetic wave receiving device characterized by:

10. The electromotive force induced in the closed loop coil is rectified and smoothed, and then output as DC power.

10. A magnetic wave receiving device according to claim 9.

11. The electromotive force induced in the closed loop coil and / or the magneto-impedance effect element or magneto-resistance element is directly amplified or mixed with a separately generated receiving station signal and amplified as an intermediate frequency signal.

11. A magnetic wave receiving device according to claim 9, wherein the magnetic wave receiving device is a magnetic wave receiving device.

12. Detecting with high accuracy the level, timing, and / or phase of said received output.

12. A magnetic wave receiving device according to claim 9, wherein the magnetic wave receiving device is a magnetic wave receiving device.

13. A plurality of sets of the closed loop coil and / or the magnetic impedance effect element or the magnetic resistance element are provided and arranged at intervals to provide a plurality of sets of reception outputs.

13. A magnetic wave receiving device according to claim 9, wherein the magnetic wave receiving device is a magnetic wave receiving device.

14. Measuring the level, timing, and / or phase of the plurality of sets of intermediate frequency signals to detect the direction and / or distance from which the received magnetic wave signals arrive.

14. A magnetic wave receiving device according to claim 9, wherein the magnetic wave receiving device is a magnetic wave receiving device.

15. A magnetic wave transmitting device according to any one of claims 1 to 8 and a magnetic wave receiving device according to any one of claims 9 to 14. A magnetic wave communication system comprising:

16. The magnetic wave transmitting device and / or the magnetic wave receiving device are carried or attached to a moving object.

16. A magnetic wave communication system according to claim 15.

17. The magnetic wave transmitting device and / or the magnetic wave receiving device are carried or attached to a plurality of moving objects, and the directions and / or distances between the moving objects are detected.

17. A magnetic wave communication system according to claim 15, wherein the magnetic wave communication system is a magnetic wave communication system.

18. The magnetic wave transmitting device and the magnetic wave receiving device are used to search for or detect conductive objects and / or reflective objects.

18. A magnetic wave communication system according to claim 15, wherein the magnetic wave communication system is a magnetic wave communication system.

19. The conductive object and / or the reflective object are carried by or attached to the moving object.

19. A magnetic wave communication system according to claim 15, wherein the magnetic wave communication system is a magnetic wave communication system.

20. The magnetic wave transmitting device has a distress detection sensor, and the magnetic wave transmitting device is automatically activated to transmit a distress signal intermittently or continuously.

20. A magnetic wave communication system according to claim 15, wherein the magnetic wave communication system is a magnetic wave communication system.

21. The magnetic wave transmitting device and / or the magnetic wave receiving device are mounted on a self-propelled means, a flying means, a boring means, or a submersible means.

21. A magnetic wave communication system according to claim 15, wherein the magnetic wave communication system is a magnetic wave communication system.

Images