JP2009027734A - High frequency coupler and electric field signal radiation element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To transmit a high frequency of UWB or the like while utilizing electric field coupling due to an electrostatic field or an induction electric field between information devices disposed within a ultra short distance. <P>SOLUTION: A resonance stab is cut, respective forward and backward metal wires supporting a coupling electrode are connected to the resonance stab to be spread over the cut portion. In order to cause a current input from a transmission/reception circuit unit via a signal line to flow toward a distal end of the resonance stab, the current once flows through one metal wire to the coupling electrode and then flows through the other metal wire to the resonance stab behind the cut portion. Namely, since there is no current component that passes through the coupling electrode and flows in the resonance stab, characteristics of a high frequency coupler are improved. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a communication apparatus that performs data communication without interfering with other communication systems between information devices arranged at a short distance or receiving interference from radio waves coming from far away, and in particular, at a short distance. The present invention relates to a communication apparatus that performs large-capacity data communication without interference with other communication systems by using electric field coupling by an electrostatic field or induction field between arranged information devices.

  Recently, when moving data between small information devices such as exchanging data such as images and music with a personal computer, it is possible to use a general-purpose cable such as an AV (Audio Visual) cable or a USB (Universal Serial Bus) cable. The use of a wireless interface is increasing instead of a method using a medium such as a connected data communication or a memory card. According to the latter, it is not necessary to change the connector and route the cable every time data is transmitted, which is convenient for the user. Many information devices equipped with various cableless communication functions have also appeared.

  In this type of data exchange, it is assumed that communication devices that transmit and receive are arranged at a relatively short distance. Under the Radio Law in Japan, the field strength (the strength of radio waves) at a distance of 3 meters from the radio equipment is below a predetermined level, that is, a weak radio that is at a noise level for other radio systems in the vicinity. If so, there is no need to obtain a radio station license, and the development and manufacturing costs of the radio system can be reduced.

  However, many of the conventional wireless communication systems such as wireless LAN (Local Area Network) and Bluetooth (registered trademark) communication represented by IEEE802.11 generate a radiated electric field generated when a current flows through an antenna (antenna). It is a radio wave communication system that propagates a signal using it, and it is difficult to suppress the generated electric field to such a weak level.

  In the radio communication system of the radio communication system, radio waves are emitted from the transmitter side regardless of whether or not there is a communication partner. Further, since the antenna on the receiver side receives not only the desired wave from the transmitter but also a radio wave arriving from a distance, it is easily affected by the surrounding interfering radio waves and causes a decrease in reception sensitivity. Further, when there are a plurality of communication partners, it is necessary to perform complicated settings in order to select a desired communication partner. For example, when a plurality of sets of wireless devices perform wireless communication in a narrow range, it is necessary to perform communication by performing division multiplexing such as frequency selection in order to avoid mutual interference. In addition, since radio waves cannot communicate when their polarization directions are orthogonal, it is necessary for the antennas to have the same polarization direction between the transceivers.

  For example, when considering a contactless data communication system at a close distance of several millimeters to several centimeters, the transmitter / receiver is strongly coupled at a short distance, while a signal is transmitted to a long distance to avoid interference with other systems. It is preferable not to arrive. In addition, it is desirable that the devices that perform data communication do not depend on each other's posture (orientation) when they are brought close to each other, and that they are coupled, that is, have no directivity. In addition, in order to perform large-capacity data communication, it is desirable that broadband communication is possible.

  The wireless communication includes a non-contact communication method using an electrostatic field or an induction electric field in addition to the radio wave communication using the radiated electric field. For example, in an existing non-contact communication system mainly used for RFID (Radio Frequency IDentification), an electric field coupling method or a magnetic field coupling method is applied. The static electric field and the induction electric field are attenuated steeply in inverse proportion to the third and second power of the distance to the distance from the source, so the electric field strength (radio wave strength) at a distance of 3 meters from the radio equipment. Is possible, and there is no need to obtain a radio station license. Also, this type of non-contact communication system does not interfere with other communication systems because no coupling relationship occurs when there is no communication partner nearby, and no electric field is radiated. Further, even when radio waves arrive from a distance, the coupler (coupler) does not receive radio waves, so that it is not necessary to receive interference from other communication systems. That is, it can be said that non-contact / ultra-short distance communication using electric field coupling by an electrostatic field or an induction electric field is suitable for realizing weak wireless.

  A contactless communication system using electric field coupling has several advantages over a normal wireless communication system. For example, when wireless signals are exchanged between devices that are relatively distant from each other, the quality of signals in the wireless section will decrease depending on the presence of surrounding reflectors and the expansion of the communication distance. Therefore, there is no dependence on the surrounding environment, and high quality transmission with a low error rate is possible using a high transmission rate. Further, in the non-contact communication system, there is no room for unauthorized devices to intercept transmission data, and it is not necessary to consider prevention of hacking and ensuring confidentiality on the transmission path.

  Further, in radio wave communication, since the antenna needs to have a size that is about one-half or one-fourth of the wavelength λ used, the apparatus inevitably increases in size. On the other hand, there is no such restriction in a non-contact communication system using electric field coupling by an induced electric field or an electrostatic field.

  For example, by forming a communication auxiliary body set in which RFID tags are positioned between a plurality of communication auxiliary bodies, and arranging RFID tags attached to a plurality of products so as to be sandwiched between the communication auxiliary bodies, RFID There has been proposed an RFID tag system that enables stable reading / writing of information even when tags are overlapped (see, for example, Patent Document 1).

  In addition to the apparatus main body and a mounting means for mounting the apparatus main body on the body, the antenna coil and data communication means for performing data communication in a non-contact manner with an external communication device via the antenna coil are provided. A data communication device using an induction magnetic field in which an antenna coil and data communication means are arranged in an outer case provided in the upper part of the device body has been proposed (see, for example, Patent Document 2). .

  In addition, an antenna coil for data communication with an external device is mounted on a memory card inserted into the portable information device, and an RFID antenna coil is disposed outside the memory card insertion slot of the portable information device. A proposal has been made on a mobile phone having an RFID that secures a communication distance without impairing portability (see, for example, Patent Document 3).

  Here, a conventional RFID system using an electrostatic field or an induction electric field uses a low frequency signal, and therefore has a low communication speed and is not suitable for a large amount of data transmission. In the case of a communication method using an induction magnetic field by an antenna / coil, if there is a metal plate on the back of the coil, communication cannot be performed, and a large area is required on the plane on which the coil is arranged. There are also implementation issues. Further, the loss in the transmission path is large, and the signal transmission efficiency is not good.

  On the other hand, the present inventors believe that a non-contact communication system capable of high-speed data transmission can be realized by propagating a broadband high-frequency signal by electric field coupling. Even in such a contactless communication system designed for speeding up, of course, since it is a weak electric field, it is not necessary to obtain a license as a radio station, and confidentiality is sufficiently ensured.

  In the radio communication system, “ultra-wide band (UWB)” is known as a wireless communication technique for realizing large-capacity data transmission by widening the bandwidth. The UWB communication system uses a very wide frequency band of 3.1 GHz to 10.6 GHz and is said to have a data transmission capacity of about 100 Mbps in spite of a short distance. Incidentally, UWB communication by radio wave communication has a communication distance of about 10 m from the relationship of transmission power, and a short-distance wireless communication system such as PAN (Personal Area Network) is assumed. For example, in IEEE 802.15.3, a data transmission system having a packet structure including a preamble has been devised as an access control system for UWB communication. In addition, Intel Corporation is considering a wireless version of USB (Universal Serial Bus), which is widely used as a general-purpose interface for personal computers, as a UWB application.

  In addition, UWB communication allows data transmission exceeding 100 Mbps without occupying a transmission band of 3.1 GHz to 10.6 GHz, and considering the ease of making an RF circuit, 3.1-4. A transmission system using a 9 GHz UWB low band is also actively developed.

  By applying this UWB low band to a contactless communication system using electric field coupling or the like, for example, in a near-field area such as an ultra-high-speed near-field DAN (Storage Area Network) including a storage device, for example, It is considered that a large amount of data such as moving images and music data for one CD can be transferred at high speed in a short time.

  Here, in the conventional RFID system, it is general that the electrodes (couplers) of the transmitter and the receiver are in close contact with each other, which is not convenient for the user. For this reason, it is considered that a form in which short distance communication is performed with the electrodes separated by about 3 cm is preferable.

  In the capacitive coupling method using a signal in a relatively low frequency band, the distance between the transmitter and receiver electrodes of 3 cm is negligible compared to the wavelength, so the propagation loss between the transmitter and receiver is It won't be a big problem. However, considering transmission of a high-frequency broadband signal such as a UWB signal, a distance of 3 cm corresponds to about a half wavelength for the used frequency band of 4 GHz. Since a propagation loss occurs according to the size of the propagation distance with respect to the wavelength, the distance between the electrodes of the transmitter and the receiver is a length that cannot be ignored compared with the wavelength. For this reason, when transmitting a UWB signal by electrostatic coupling, it is necessary to suppress the propagation loss sufficiently low.

  In addition, a frequency spreading method such as DSSS (Direct Sequence Spread Spectrum) is also applied to an ultra short-range communication system that transmits a UWB communication signal using electric field coupling by an electrostatic field or an induction electric field. In some cases, it is necessary not only to generate electric field coupling in the high frequency band between the couplers of the transceiver, but also to design the coupler to operate effectively in a wide band. When the coupler is housed in the housing of the device, it is assumed that the center frequency is shifted due to the influence of the surrounding metal parts, and from this point of view, the coupler for electric field coupling operates effectively at a wide frequency in advance. Need to design.

JP 2006-60283 A JP 2004-214879 A JP 2005-18671 A

  An object of the present invention is to provide an excellent communication apparatus capable of performing data communication without interfering with other communication systems between information devices arranged at a short distance or receiving interference from radio waves coming from a distance. Is to provide.

  A further object of the present invention is to make it possible to perform large-capacity data communication without interference with other communication systems by utilizing electric field coupling by an electrostatic field or an induction electric field between information devices arranged at a short distance. The object is to provide an excellent communication device.

  A further object of the present invention is to provide an excellent communication device capable of transmitting a high-frequency signal such as UWB between information devices arranged at a short distance by using electric field coupling by an electrostatic field or an induction electric field. is there.

The present invention has been made in consideration of the above problems, and a communication circuit unit for processing a high-frequency signal for transmitting data;
A high-frequency coupler connected to the communication circuit unit via a signal line for transmitting a high-frequency signal, and for electric field coupling with a communication partner facing each other at a short distance;
The high-frequency coupler includes a coupling electrode, a resonance unit including a distributed constant circuit for strengthening electrical coupling between the coupling electrodes, and a first unit that supports the coupling electrode with respect to the resonance unit. And a second metal wire,
Transmitting the high-frequency signal by electric field coupling of an electrostatic field or an induction electric field with a high-frequency coupler on the communication partner side,
It is a communication apparatus characterized by this.

  Many wireless communication systems typified by wireless LANs use a radiated electric field that is generated when a current is passed through an antenna, so that radio waves are emitted regardless of whether there is a communication partner. In addition, the radiated electric field attenuates gently in inverse proportion to the distance from the antenna, so that the signal reaches a relatively far distance and becomes a source of disturbing radio waves to nearby communication systems, and the antenna on the receiver side also surrounds it. The reception sensitivity decreases due to the effects of interference. In short, in the radio wave communication system, it is difficult to realize wireless communication limited to a communication partner at a short distance.

  On the other hand, in a non-contact communication system including a transmitter that generates high-frequency signals such as UWB that transmits data and a receiver that receives and processes high-frequency signals, using electric field coupling by an electrostatic field or an induction electric field. When there is no communication partner nearby, the connection relationship does not occur. In addition, the electric field strengths of the induction electric field and the electrostatic field are steeply attenuated in inverse proportion to the square and the cube of the distance, respectively. That is, since the electric field does not reach far, other communication systems are not disturbed. Further, even when radio waves arrive from a distance, the coupling electrode does not receive radio waves, so that it is not necessary to receive interference from other communication systems. Therefore, weak radio that does not require a radio station license is possible, and it is not necessary to consider prevention of hacking and ensuring confidentiality on the transmission path. In addition, since it is a broadband communication using high-frequency signals such as UWB, it is possible to perform a large-capacity communication over a very short distance. For example, a large amount of data such as a moving image or music data for one CD can be transmitted at high speed in a short time. Can be transferred.

  Here, in the high frequency circuit, a propagation loss occurs according to the propagation distance with respect to the wavelength. Therefore, when transmitting a high frequency signal such as UWB by electric field coupling, it is necessary to suppress the propagation loss sufficiently low.

  Therefore, in the electric field coupling type non-contact communication system using the high frequency signal, the high frequency coupler of the transmitter and the receiver includes a resonance unit and an impedance matching unit. While the electric field coupling is strengthened by the mutual resonance parts, the impedance matching part can match the impedance between the electrodes of the transmitter and the receiver, that is, the coupling part, and suppress the reflected wave. In other words, the pair of high frequency couplers of the transmitter and the receiver are configured to operate as a band pass filter that passes a desired high frequency band.

  The impedance matching unit and the resonance unit can be configured by a lumped constant circuit in which a series inductor and a parallel inductor are connected to a high-frequency signal transmission path, for example. However, since the lumped constant circuit determines constants such as inductance L and capacitance C based on the center frequency, impedance matching is not achieved in a band outside the assumed center frequency, and the operation as designed is do not do. In other words, it works effectively only in a narrow band. Particularly in the high frequency band, the resonance frequency is influenced by the fine structure of the lumped constant circuit portion and the variation of inductors and capacitors having a small value, so that it is difficult to adjust the frequency. In addition, when the impedance matching part and the resonance part are configured with lumped constants, if a small chip inductor is used as the inductor, there is a loss inside the chip inductor, and the propagation loss between the high frequency couplers becomes large. is there. Also, when the coupler is housed in the housing of the device, the center frequency is assumed to be shifted due to the influence of surrounding metal parts, so the coupler is designed to operate effectively at a wide frequency beforehand. There is a need.

  Therefore, the high-frequency coupler includes a coupling electrode and an impedance matching unit or a resonance unit for matching impedance between the coupling electrodes, but the resonance unit is configured by replacing the lumped constant circuit with the distributed constant circuit. By doing so, a wide band can be realized.

  The high-frequency coupler is mounted on a printed circuit board as one of the mounting components, similarly to the circuit module constituting the communication circuit unit that processes the high-frequency signal for transmitting data. In such a case, the distributed constant circuit as the resonance unit can be formed as a stub of a microstrip line or a coplanar waveguide on a dielectric substrate such as a so-called printed circuit board together with a signal line output from the communication circuit unit. .

  A ground is formed on the other surface of the printed circuit board on which the high-frequency coupler is mounted, but the front end portion of the stub may be an open end or through the through hole in the printed circuit board. It may be connected to a short circuit end.

  The high-frequency coupler is configured by attaching a coupling electrode on a stub as a distributed constant circuit. Since the mechanical strength is low when the coupling electrode is supported by a single metal wire, it may be supported by an insulating spacer. However, in this case, the component cost and weight increase, and because of the dielectric loss due to the spacer, the high frequency coupler is used. There is a problem that the propagation loss of the above becomes worse. On the other hand, if the coupling electrode is supported by a plurality of metal wires, the mechanical strength increases, but the current input to the resonance stub does not easily flow into the coupling electrode. Rather, the target characteristics deteriorate.

  Therefore, in the present invention, the resonance stub is cut into two, a first resonance stub on the tip end side and a second resonance stub on the input end side, and two metals before and after supporting the coupling electrode. A configuration is adopted in which the wire is connected to the resonance stub so as to straddle the cut portion, so that the current passing through the resonance stub without flowing through the coupling electrode is suppressed. In such a case, in order for the current input from the transmission / reception circuit unit to flow toward the tip of the resonance stub, the current once flows to the coupling electrode through one metal wire and then passes through the other metal wire. It flows into the resonance stub after the cut portion. That is, since there is no current component flowing through the resonance stub through the coupling electrode, the characteristics of the high frequency coupler can be improved by increasing the amount of current input to the resonance stub.

  Here, the signal input from the transmission / reception circuit via the signal line is reflected at the tip of the resonance stub, and a standing wave is generated in the resonance stub. The electrical characteristics of the high-frequency coupler are excellent by connecting the coupling electrode to the position where the amplitude of the voltage standing wave is large (that is, the position of the “antinode” of the voltage standing wave) via a metal wire. Can be.

  Here, the tip portion of the first resonance stub may be either an open end or a short-circuit end, but the standing wave is different depending on whether it is an open end or a short-circuit end, and the voltage standing The position where the wave amplitude is large, i.e. the appropriate position to attach the coupling electrode, is different.

  When the first resonance stub is an open end, if the entire length including the resonance stub, the metal wire, and the coupling electrode is approximately 360 degrees as the phase length of the resonance frequency, it is approximately at the center. Since the amplitude of the voltage standing wave becomes large in FIG. 2, the resonance stub is cut into the first and second resonance stubs at approximately the center, and the cut portion is connected by two metal wires. It is preferable to attach.

  On the other hand, when the first resonance stub is short-circuited, the total length including the resonance stub, the metal wire, and the coupling electrode is approximately 270 degrees as the phase length of the resonance frequency. Since the amplitude of the voltage standing wave increases at a position one third from the front end of one resonance stub (or two thirds from the input end), the resonance stub is placed at the first and second positions at the position. It is preferable to cut the second resonance stub and attach the coupling electrode so that the cut portion is connected by two metal wires. Actually, in consideration of the phase transition inside the metal wire and the coupling electrode, the first and second positions at a predetermined position that is slightly closer to the front end than a third from the short-circuited end of the first resonance stub. It is preferable to provide a cutting part that divides the second resonance stub.

  Further, when the coupling electrode is supported by a single metal wire, there is a concern that an unnecessary radio wave is generated due to current flowing through the metal wire. On the other hand, when the coupling electrode is supported by two metal wires, the currents cancel each other if the coupling electrodes are installed at positions where currents flowing in opposite directions flow in the respective metal wires. In combination, unnecessary radio wave radiation can be reduced.

  If the high-frequency coupler that transmits a high-frequency signal is designed ideally, generation of unnecessary radio waves can be suppressed and reception of external radio waves can be prevented when coupled with a communication partner. However, since there is a high impedance in a no-load state that is not coupled with the communication partner, there is a problem that a reflected wave is generated at the coupling electrode serving as a termination, and a standing wave is generated in the circuit. If the standing wave causes the signal line or the ground to operate like an antenna and emits unnecessary radio waves, it may affect external electronic devices.

  Therefore, the communication device according to the present invention has a high-frequency coupler that has a large impedance in the no-load state and can be regarded as the open end, and a reflected wave from the end of the high-frequency coupler that occurs in the no-load state. A load resistor for suppressing the impedance may be provided, and as a result, impedance matching on the high frequency coupler side as viewed from the transmission / reception circuit side may be obtained.

  In such a case, impedance matching is achieved when viewed from the transmission / reception circuit side even in a no-load state where the high-frequency couplers are not close to each other, and no reflected wave is generated at the terminal electrode. The wave can be suppressed. As a result, unnecessary radio wave radiation is suppressed and the influence on external electronic devices is small. In addition, the RF filter and the like operate normally, and signal distortion and spurious can be prevented.

  The load resistor is preferably connected to a position where the voltage amplitude of the standing wave is maximized, such as the input end of the resonance stub.

  Further, as one design theory for flexibly generating electric field coupling between transceivers, a configuration in which a plurality of high-frequency couplers are arranged in a single transceiver can be considered. For example, a plurality of high-frequency couplers can be connected in parallel to one signal line connected to the transmission / reception circuit unit. At this time, it is configured so that the no-load high-frequency coupler is handled as an open end, in other words, each high-frequency coupler can be connected so as to branch at a position where the voltage standing wave at the time of no-load becomes large. It is the most efficient. For this purpose, when the tip of the first resonance stub is an open end, the length from the tip is configured to be connected to the signal line at a position that is approximately an integral multiple of one-half wavelength of the resonance frequency. Good.

  The high frequency coupler according to the present invention can control the propagation loss and the ratio band by the width of the resonance stub. Specifically, the loss is small when the stub width is large. Moreover, the smaller the stub width, the wider the specific band.

  Further, the coupling electrode of the high-frequency coupler according to the present invention can be easily and inexpensively manufactured by sheet metal processing, for example. As the sheet metal, for example, a phosphor bronze sheet whose surface is plated with gold can be used. Specifically, the sheet metal is first punched to form a portion to be a coupling electrode and a portion to be two metal wires for connecting the coupling electrode and the high-frequency signal line. Subsequently, a bending process is performed to bend a leg portion serving as a metal wire substantially perpendicularly to the coupling electrode portion to form a desired height. Then, the coupling electrode thus completed is positioned such that the cut portion of the first and second resonance stubs straddles the two leg portions at a corresponding place on the printed circuit board, for example, a jig, etc. After fixing with, reflow solder or the like may be used.

  Advantageous Effects of Invention According to the present invention, an excellent communication device capable of performing data communication without interfering with other communication systems between information devices arranged at a short distance or receiving interference from radio waves arriving from a distance. Can be provided.

  In addition, according to the present invention, high-capacity data communication is performed without interference with other communication systems by high-frequency signal transmission using electric field coupling by an electrostatic field or an induction electric field between information devices arranged at a short distance. It is possible to provide an excellent communication device.

  The communication device according to the present invention includes a coupling electrode, a resonance unit for strengthening electric field coupling with a communication partner, and an impedance matching unit that suppresses reflected waves at the coupling part by matching impedance with the communication partner side. The data transmission can be performed using the electric field coupling by the electrostatic field or the induction electric field with the high frequency coupling on the communication partner side.

  The resonance part of the high-frequency coupler is formed by a resonance stub such as a microstrip line or a coplanar waveguide on a printed circuit board, and can function as a distributed constant circuit to achieve a wide band. Further, the resonance stub is cut at an appropriate position, and the coupling electrode is supported by two metal wires straddling the cut portion, so that the mechanical strength is higher than that in the case of supporting by one metal wire. Can be increased. Further, since the current flowing from the resonance stub to the coupling electrode is increased by supporting with two metal wires, the communication efficiency can be improved, and the propagation loss compared with the case of supporting with one metal wire. Does not get worse.

  The coupling electrode having two metal wires to be supported is formed integrally with the two metal wires by, for example, sheet metal processing, and is mounted on the surface of the printed circuit board by reflow soldering or the like, thereby increasing the mechanical strength. Since an insulating spacer for supporting the coupling electrode is not required, the component cost and weight are reduced, and propagation loss due to dielectric loss does not occur. Therefore, the characteristics as a high frequency coupler are excellent.

  Also, if the coupling electrodes are arranged so that currents flowing in opposite directions flow through the two metal wires, the currents flowing through the two metal wires cancel each other, reducing the emission of unwanted radio waves in the lateral direction. Can do.

  Other objects, features, and advantages of the present invention will become apparent from more detailed description based on embodiments of the present invention described later and the accompanying drawings.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  The present invention relates to a communication system that performs data transmission between information devices using electric field coupling of an electrostatic field or an induction electric field. According to a communication method based on an electrostatic field or an induced electric field, when there is no communication partner nearby, there is no coupling relationship and no radio waves are emitted, so that other communication systems are not disturbed. Further, even when radio waves arrive from a distance, the coupler does not receive radio waves, so that it is not necessary to receive interference from other communication systems.

  In the conventional radio communication using an antenna, the electric field strength of the radiated electric field is inversely proportional to the distance, whereas in the induced electric field, the electric field strength is inversely proportional to the distance squared, and in the static electric field, the electric field strength is inversely proportional to the cube of the distance. Therefore, according to the communication method based on electric field coupling, it is possible to configure a weak radio having a noise level for other radio systems in the vicinity, and it is not necessary to obtain a license from the radio station.

  An electrostatic field that varies with time may be referred to as a “quasi-electrostatic field”. In this specification, however, the electrostatic field is collectively referred to as an “electrostatic field”.

  Conventional communication using an electrostatic field or an induction field uses a low-frequency signal and is not suitable for transmitting a large amount of data. On the other hand, in the communication system according to the present invention, high-capacity transmission is possible by transmitting a high-frequency signal by electric field coupling. Specifically, by applying a communication method using a high frequency and a wide band, such as UWB communication, to electric field coupling, it is possible to realize weak data and large capacity data communication.

  UWB communication uses a very wide frequency band of 3.1 GHz to 10.6 GHz, and can realize high-capacity wireless data transmission of about 100 Mbps despite a short distance. In addition, UWB communication allows data transmission exceeding 100 Mbps without occupying a transmission band of 3.1 GHz to 10.6 GHz, and considering the ease of making an RF circuit, 3.1-4. A transmission system using a 9 GHz UWB low band is also actively developed.

  The present inventors consider that a data transmission system using UWB low band is one of effective wireless communication technologies installed in mobile devices. For example, it is possible to realize high-speed data transmission in a short-distance area such as an ultra-high-speed short-range DAN (Device Area Network) including a storage device. According to a UWB communication system using electric field coupling such as an electrostatic field and an induction field, data communication by a weak electric field is possible and, for example, a large amount of data such as a moving image or music data for one CD can be quickly and quickly. I think it can be transferred with.

  FIG. 1 shows a configuration example of a non-contact communication system using electric field coupling by an electrostatic field or an induction electric field. The illustrated communication system includes a transmitter 10 that transmits data and a receiver 20 that receives data. As shown in the figure, when the high-frequency couplers of the transceivers are arranged face to face, the two electrodes operate as one capacitor, and as a whole operate like a band-pass filter, the two high-frequency couplers High-frequency signals can be efficiently transmitted between the two. In the communication system shown in the figure, in order to suitably form a transmission path by electric field coupling, sufficient impedance matching is achieved between the high-frequency couplers of the transmitter and receiver, and it operates effectively in a high frequency band and in a wide band. It is necessary to.

  The transmitter / receiver electrodes 14 and 24 of the transmitter 10 and the receiver 20 are disposed to face each other with a spacing of, for example, about 3 cm, and can be coupled to each other. The transmission circuit unit 11 on the transmitter side generates a high-frequency transmission signal such as a UWB signal based on transmission data when a transmission request is generated from a higher-level application, and the signal propagates from the transmission electrode 14 to the reception electrode 24. Then, the receiving circuit unit 21 on the receiver 20 side demodulates and decodes the received high-frequency signal and passes the reproduced data to the upper application.

  According to a communication method using a high frequency and a wide band like UWB communication, it is possible to realize ultrahigh-speed data transmission of about 100 Mbps at a short distance. In addition, when UWB communication is performed by electric field coupling instead of radio wave communication, the electric field strength is inversely proportional to the cube of the distance or the square of the distance, so the electric field strength (radio wave strength) at a distance of 3 meters from the radio equipment is By suppressing the frequency to a predetermined level or less, it is possible to obtain a weak radio that does not require a radio station license, and a communication system can be configured at low cost. In addition, when data communication is performed at an extremely short distance by the electric field coupling method, the signal quality is not deteriorated by the reflecting objects present in the vicinity, and it is not necessary to consider the prevention of hacking and ensuring the confidentiality on the transmission line. There are advantages such as.

  On the other hand, since the propagation loss increases according to the propagation distance with respect to the wavelength, it is necessary to sufficiently suppress the propagation loss when a high-frequency signal is propagated by electric field coupling. In a communication system that transmits high-frequency broadband signals such as UWB signals by electric field coupling, even ultra-short-distance communication of about 3 cm is equivalent to about one-half wavelength for the used frequency band of 4 GHz, so it is ignored. It is a length that cannot be done. In particular, the problem of characteristic impedance is more serious in a high-frequency circuit than in a low-frequency circuit, and the influence of impedance mismatch becomes apparent at the coupling point between the electrodes of the transceiver.

In communication using frequencies in the kHz or MHz band, the propagation loss in space is small, so that the transmitter and receiver have a coupler consisting only of electrodes as shown in FIG. 2, and the coupling part is simply a parallel plate capacitor. Even in the case of operating as, it is possible to perform desired data transmission. However, in communication using high frequency in the GHz band, since propagation loss in space is large, it is necessary to suppress signal reflection and improve transmission efficiency. As shown in FIG. 3, even if the high-frequency signal transmission path is adjusted to a predetermined characteristic impedance Z ₀ in each of the transmitter and the receiver, impedance matching is performed at the coupling portion only by coupling with a parallel plate capacitor. I can't take it. For this reason, in the impedance mismatching part in a coupling part, a signal is reflected, a propagation loss arises, and efficiency falls. For example, even if the high-frequency signal transmission line connecting the transmission circuit unit 11 and the transmission electrode 14 is a coaxial line with 50Ω impedance matching, the impedance at the coupling portion between the transmission electrode 14 and the reception electrode 24 is low. If they are mismatched, the signal is reflected to cause a propagation loss.

  Therefore, as shown in FIG. 4, the high-frequency couplers disposed in the transmitter 10 and the receiver 20 are connected to the plate-like electrodes 14 and 24, the series inductors 12 and 22, and the parallel inductors 13 and 23, respectively. Connected to the transmission line. When such a high-frequency coupler is disposed facing each other as shown in FIG. 5, the two electrodes operate as one capacitor and operate like a band-pass filter as a whole. High-frequency signals can be efficiently transmitted between the two. Here, the high-frequency signal transmission line indicates a coaxial cable, a microstrip line, a coplanar line, or the like.

  Here, if the purpose is simply to perform impedance matching between the electrodes of the transmitter 10 and the receiver 20, that is, the coupling portion, to suppress the reflected wave, each coupler is connected as shown in FIG. 6A. It is not necessary to configure the flat electrodes 14 and 24, the series inductors 12 and 22 and the parallel inductors 13 and 23 to be connected to the high-frequency signal transmission path, and each coupler is formed as a flat electrode 14 as shown in FIG. 6B. , 24 and a series inductor may be connected to a high-frequency signal transmission line. That is, even when a series inductor is inserted on the high-frequency signal transmission line, when there is a coupler on the receiver side at a very short distance facing the coupler on the transmitter side, the impedance at the coupling portion becomes continuous. It is possible to design as such.

However, in the configuration example shown in FIG. 6B, there is no change in the characteristic impedance before and after the coupling portion, so the magnitude of the current does not change. On the other hand, as shown in FIG. 6A, when connected to the ground via the parallel inductance before the electrode at the end of the high-frequency signal transmission path, the coupler alone has the characteristic impedance Z ₀ on the near side of the coupler. On the other hand, the characteristic impedance Z _{1 at} the end of the coupler is reduced (that is, Z ₀ > Z ₁ ), so that it has a function as an impedance conversion circuit, and the output current of the coupler with respect to the input current I ₀ to the coupler. I ₁ can be amplified (ie, I ₀ <I ₁ ).

  7A and 7B show a state in which an electric field is induced by electric field coupling between electrodes in each of the couplers with and without the parallel inductance. From this figure, it can be understood that the coupler is provided with a parallel inductor in addition to the series inductor, thereby inducing a larger electric field and causing strong coupling between the electrodes. When a large electric field is induced near the electric field as shown in FIG. 7A, the generated electric field propagates in the front direction of the electrode surface as a longitudinal wave that vibrates in the traveling direction. This electric wave makes it possible to propagate a signal between the electrodes even when the distance between the electrodes is relatively large.

  Therefore, in a communication system that transmits high-frequency signals such as UWB signals by electric field coupling, the essential conditions for a high-frequency coupler are as follows.

(1) There is an electrode for coupling by an electric field.
(2) There is a parallel inductor for coupling with a stronger electric field.
(3) In the frequency band used for communication, the inductor and capacitor constants are set so that impedance matching can be achieved when the coupler is placed face to face.

As shown in FIG. 5, the band-pass filter comprising a pair of high-frequency couplers whose electrodes face each other has its pass frequency f ₀ determined by the inductance of the series inductor and the parallel inductor and the capacitance of the capacitor constituted by the electrodes. can do. FIG. 8 shows an equivalent circuit of a bandpass filter composed of a set of high-frequency couplers. If the characteristic impedance R [Ω], the center frequency f ₀ [Hz], the phase difference between the input signal and the passing signal is α [radian] (π <α <2π), and the capacitance of the capacitor constituted by the electrodes is C / 2. The constants L ₁ and L ₂ of the parallel and series inductances constituting the band pass filter can be obtained by the following equations according to the operating frequency f ₀ .

Further, when the coupler functions as an impedance conversion circuit as a single unit, the equivalent circuit is as shown in FIG. In the illustrated circuit diagram, an impedance conversion circuit that converts the characteristic impedance from R ₁ to R ₂ by selecting the parallel inductance L ₁ and the series inductance L ₂ in accordance with the operating frequency f ₀ so as to satisfy the following equation. Can be configured.

  As described above, in the non-contact communication system shown in FIG. 1, a communication device that performs UWB communication uses the high-frequency coupler shown in FIG. 4 instead of using an antenna in a conventional radio communication device of radio wave communication system. As a result, it is possible to realize ultra-short distance data transmission having unprecedented characteristics.

  As shown in FIG. 5, the two high-frequency couplers whose electrodes face each other with a very short distance operate as a band-pass filter that passes a signal in a desired frequency band, and a single high-frequency coupler. Acts as an impedance conversion circuit that amplifies the current. On the other hand, when the high-frequency coupler is placed alone in free space, the input impedance of the high-frequency coupler does not match the characteristic impedance of the high-frequency signal transmission path, so that the signal entering from the high-frequency signal transmission path is reflected in the high-frequency coupler. Not radiated outside.

  Therefore, in the non-contact communication system shown in FIG. 1, when there is no partner to communicate with on the transmitter side, radio waves do not flow like an antenna, and the partner to communicate with approaches each electrode. Only when a capacitor is formed, high-frequency signals are transmitted by impedance matching as shown in FIG.

Here, consider the electromagnetic field generated in the coupling electrode on the transmitter side. FIG. 10 shows an electromagnetic field generated by a minute dipole. As shown in the figure, the electromagnetic field is roughly divided into an electric field component (transverse wave component) E _θ that vibrates in a direction perpendicular to the propagation direction and an electric field component (longitudinal wave component) E _R that vibrates in a direction parallel to the propagation direction. . In addition, a magnetic field _Hφ is generated around the minute dipole. The following equation represents the electromagnetic field due to a small dipole, but since an arbitrary current distribution can be considered as a continuous collection of such small dipoles, the electromagnetic field induced thereby has similar properties (for example, (See Yasunori Mushiaki, “Antenna / Radio Wave Propagation” (Corona, pages 16-18, first published on February 28, 1961)).

As can be seen from the above equation, the transverse wave component of the electric field includes a component that is inversely proportional to the distance (radiated electric field), a component that is inversely proportional to the square of the distance (induced electric field), and a component that is inversely proportional to the cube of the distance (electrostatic field). ). Further, the longitudinal wave component of the electric field is composed only of a component that is inversely proportional to the square of the distance (inductive electric field) and a component that is inversely proportional to the cube of the distance (electrostatic field), and does not include the component of the radiation electric field. Further, the electric field E _R becomes maximum in the direction in which | cos θ | = 1, that is, in the direction of the arrow in FIG.

In the radio communications are widely used in wireless communication, radio wave emitted from an antenna is a transverse wave E _theta oscillating in the perpendicular direction its traveling direction, the radio wave can not communicate with the direction of polarization is orthogonal. In contrast, electromagnetic waves emitted from the coupling electrode in a communication system utilizing an electrostatic field or an induced electric field, in addition to the transverse wave E _theta, including longitudinal wave E _R which oscillates in the traveling direction. The longitudinal wave E _R is also called “surface wave”. Incidentally, a surface wave can also propagate through the inside of a medium such as a conductor, a dielectric material, or a magnetic material.

  Of the transmission waves using an electromagnetic field, those having a phase velocity v smaller than the light velocity c are called slow waves, and those having a larger phase velocity v are called fast waves. The surface wave corresponds to the former slow wave.

In a non-contact communication system, a signal can be transmitted via any component of a radiated electric field, an electrostatic field, and an induced electric field. However, a radiated electric field that is inversely proportional to distance can cause interference to other systems that are relatively far away. Therefore, to suppress the component of the radiation field, in other words, while suppressing the transverse wave E _theta comprising the components of the radiation field, the non-contact communication is preferred utilizing longitudinal wave E _R not containing component of the radiation field.

From the viewpoint described above, the high frequency coupler according to the present embodiment is devised as follows. First, it can be seen from the above-described three equations showing the electromagnetic field that E _θ = 0 and the E _R component takes a maximum value when θ = 0 °. That is, E _θ is maximized in a direction perpendicular to the direction of current flow, and E _R is maximized in a direction parallel to the direction of current flow. Therefore, to maximize E _R perpendicular front direction with respect to the electrode surface, it is desirable to increase the vertical direction of the current component to the electrode. On the other hand, when the feeding point is offset from the center of the electrode, the current component in the direction parallel to the electrode increases due to this offset. Then, the front direction of the E _theta component of the electrode according to the current component is increased. Therefore, in the high-frequency coupler according to the present embodiment, the feeding point provided as close as possible to the center position of the electrode is the E _R component is set to be maximum.

Of course, not only the radiated electric field but also the static electric field and the induced electric field are generated in the conventional antenna, and the electric field coupling occurs when the transmitting and receiving antennas are brought close to each other. However, most of the energy is emitted as the radiated electric field, which is efficient for contactless communication In addition, there are concerns about the adverse effects of unnecessary radio waves on nearby electronic devices. In contrast, the high-frequency coupler shown in Fig. 4, so as to increase the transmission efficiency create a stronger electric field E _R at a predetermined frequency, the electrode and the resonance unit for coupling is formed. In addition, by using a wave absorber made of magnetic loss material in the vicinity of the coupling electrode, it is possible to reduce the effects of unnecessary radio waves and external interference waves while stabilizing the electric field coupling between the transmitter and receiver at a short distance. suppress.

When the high-frequency coupler shown in FIG. 4 is used alone on the transmitter side, a longitudinal wave electric field component E _R is generated on the surface of the coupling electrode, but the transverse wave component E _θ including the radiation electric field is changed to E _R. Since it is relatively small, almost no radio waves are emitted. That is, no disturbing wave to other neighboring systems is generated. Also, most of the signal input to the high frequency coupler is reflected by the electrode and returns to the input end.

On the other hand, when one set of high-frequency couplers is used, that is, when the high-frequency couplers are arranged at a short distance between the transmitter and the receiver, the coupling electrodes are coupled mainly by a quasi-electrostatic field component to form one capacitor. It works like a bandpass filter and is in a state where impedance matching is achieved. Therefore, most of the signal / power is transmitted to the other party in the passing frequency band, and the reflection to the input end is small. The “short distance” here is defined by the wavelength λ, and corresponds to the distance d between the coupling electrodes being d << λ / 2π. For example, when the use frequency f ₀ is 4 GHz, the distance between the electrodes is 10 mm or less.

Also, when placing the EFC medium distance between the transmitter and the receiver are on the periphery of the coupling electrode of the transmitter, the electrostatic field is attenuated, the longitudinal wave electric field E _R mainly composed of an induced electric field is generated . Longitudinal wave electric field E _R is received by the coupling electrode of the receiver, the signal is transmitted. However, in comparison with the case where both couplers are arranged at a short distance, in the high frequency coupler on the transmitter side, the ratio of the input signal reflected by the electrode and returning to the input end becomes higher. The “medium distance” here is defined by the wavelength λ, the distance d between the coupling electrodes is about 1 to several times larger than λ / 2π, and the distance between the electrodes is 10 to 40 mm when the use frequency f ₀ is 4 GHz. At the time.

As described above, in the high-frequency coupler shown in FIG. 4, the operating frequency f ₀ of the impedance matching unit is determined by the constants L ₁ and L ₂ of the parallel inductor and the series inductor. It is a general circuit manufacturing method to configure these series inductors 12 and 22 and parallel inductors 13 and 23 with circuit elements that are regarded as lumped constant circuits. However, it is known that a lumped constant circuit has a narrower band than a distributed constant circuit in a high-frequency circuit, and the inductor constant becomes small when the frequency is high, so that there is a problem that the resonance frequency shifts due to variations in the constant.

  In view of this, a high frequency coupler is configured by replacing the lumped constant circuit with the distributed constant circuit for the impedance matching section and the resonance section, thereby realizing a wide band. FIG. 11 shows a configuration example of a high-frequency coupler using a distributed constant circuit for the impedance matching unit and the resonance unit.

  In the illustrated example, a high-frequency coupler is disposed on a printed circuit board 101 having a ground conductor 102 formed on the lower surface and a printed pattern formed on the upper surface. Instead of a parallel inductor and a series inductor, a microstrip line or a coplanar waveguide, that is, a stub 103 is formed as an impedance matching unit and a resonance unit of a high frequency coupler, and a transmission / reception circuit is connected via a signal line pattern 104. The module 105 is connected. The stub 103 is connected to the ground 102 on the lower surface via a through hole 106 penetrating the printed circuit board 101 at the tip, and is short-circuited, and is connected to the coupling electrode 108 via a metal wire 107 near the center of the stub 103. Is done.

  The “stub” in the technical field of electronics is a general term for electric wires with one end connected and the other end not connected or connected to the ground, and is used for adjustment, measurement, impedance matching, filters, etc. Provided on the way.

  A signal input from the transmission / reception circuit via the signal line is reflected at the tip of the stub 103, and a standing wave is generated in the stub 103. The length of the stub 103 is about a half wavelength of the high frequency signal, and the signal line 104 and the stub 103 are formed by a microstrip line, a coplanar line, or the like on the printed circuit board 101. When the length of the stub 103 is a half wavelength and the tip is short-circuited, the voltage amplitude of the standing wave generated in the stub 103 becomes 0 at the tip of the stub, and from the center of the stub, that is, from the tip of the stub 103. It is maximum at a quarter wavelength (see FIG. 12). By connecting the coupling electrode 108 with the metal wire 107 at the center of the stub 103 where the voltage amplitude of the standing wave is maximized, a high-frequency coupler with good propagation efficiency can be made.

  Since the impedance matching section is composed of a stub 103, that is, a distributed constant circuit composed of a microstrip line or a coplanar waveguide on the printed circuit board 101, uniform characteristics can be obtained over a wide band. Therefore, the communication system shown in FIG. On the other hand, it is possible to apply a modulation scheme that spreads a frequency to a wideband signal such as DSSS and OFDM (Orthogonal Frequency Division Multiplexing). The stub 103 is a microstrip line or a coplanar waveguide on the printed circuit board 101, and since its direct current resistance is small, there is little loss even for a high-frequency signal, and propagation loss between high-frequency couplers can be reduced.

  Since the size of the stub 103 constituting the distributed constant circuit is as large as about a half wavelength of a high-frequency signal, the dimensional error due to manufacturing tolerances is very small compared to the overall length, resulting in variations in characteristics. Hateful.

  FIG. 13 shows a comparison of frequency characteristics of the high-frequency coupler when the impedance matching unit is composed of a lumped constant circuit and a distributed constant circuit. However, the high-frequency coupler in which the impedance matching unit is configured by a lumped constant circuit, as shown in FIG. 14, a coupling electrode is disposed at the tip of the signal line pattern on the printed circuit board via a metal wire, and the signal line It is assumed that a parallel inductor component is mounted at the tip of the pattern, and the other end of the parallel inductor is connected to a ground conductor through a through hole in the printed circuit board. Moreover, as shown in FIG. 15, the high frequency coupler which comprised the impedance matching part with the distributed constant circuit has a metal wire in the center of the stub formed on the printed circuit board and having a length of a half wavelength. It is assumed that a coupling electrode is provided and the stub is connected to the ground conductor at the tip thereof through a through hole in the printed circuit board. It is assumed that each high frequency coupler is adjusted so that the operating frequency is around 3.8 GHz. 14 and 15, a high frequency signal is transmitted from the port 1 to the port 2 by the microstrip line, and each high frequency coupler is disposed in the middle of the microstrip line. The frequency characteristic is measured as a transfer characteristic from port 1 to port 2 and the result is shown in FIG.

Since the high-frequency coupler can be regarded as an open end when it is not coupled with other high-frequency couplers, the high-frequency signal input from the port 1 is not supplied to the high-frequency coupler but is transmitted to the port 2 as it is. Therefore, in the vicinity of 3.8 GHz, which is the operating frequency of the high frequency coupler, the propagation loss S ₂₁ representing the signal intensity transmitted from the port 1 to the port 2 is a large value in either high frequency coupler. However, in the case of the high frequency coupler shown in FIG. 14, the value of S ₂₁ is greatly reduced at a frequency deviating back and forth from the operating frequency. On the other hand, it can be seen that the high frequency coupler shown in FIG. 15 maintains good characteristics with a large value of S ₂₁ over a wide frequency band centered on the operating frequency. That is, it can be said that the high-frequency coupler operates effectively in a wide band by configuring the impedance matching unit with a distributed constant circuit.

  In the vicinity of the center of the stub 103, the coupling electrode 108 is connected via the metal wire 107, and it is preferable that the metal wire is connected at the approximate center of the coupling electrode 108. This is because, by connecting a high-frequency transmission line to the center of the coupling electrode, current flows evenly in the electrode, and unnecessary radio waves are not emitted in the direction substantially perpendicular to the electrode surface in front of the electrode (see FIG. 16A). For example, if a high-frequency transmission line is connected at a position offset from the center of the coupling electrode, an unequal current flows in the termination electrode and operates like a microstrip antenna, radiating unnecessary radio waves. (See FIG. 16B).

  Also, in the field of radio wave communication, as shown in FIG. 17, a “capacitance loaded type” antenna is widely known in which a metal is attached to the tip of an antenna element to provide a capacitance, and the height of the antenna is shortened. At first glance, the structure is similar to the coupler shown in FIG. Here, the difference between the coupler used in the transceiver in this embodiment and the capacity loaded antenna will be described.

The capacitively loaded antenna shown in FIG. 17 emits radio waves in the directions B ₁ and B ₂ around the radiating element of the antenna, but the A direction is a null point that does not radiate radio waves. When the electric field generated around the antenna is examined in detail, the radiation electric field attenuated in inverse proportion to the distance from the antenna, the induced electric field attenuated in inverse proportion to the square of the distance from the antenna, and the distance from the antenna 3 An electrostatic field that decays in inverse proportion to the power is generated. Since the induced electric field and the electrostatic field are attenuated more rapidly depending on the distance than the radiated electric field, only the radiated electric field is discussed in a normal wireless system, and the induced electric field and the electrostatic field are often ignored. Therefore, even the capacitively loaded antenna shown in FIG. 17 generates an induction electric field and an electrostatic field in the direction A, but since it attenuates quickly in the air, it is actively used in radio communication. Absent.

  An actual configuration example of the high-frequency coupler will be described with reference to FIGS. FIG. 18 shows a high-frequency coupler in which the stub 103 is bent under the coupling electrode 108. In order to operate as a high frequency coupler, the length of the stub 103 need only be about one-half wavelength, and the stub 103 does not necessarily have to be a straight line. Therefore, by folding as shown in FIG. The overall dimensions of the vessel can be reduced.

  As described above, from the viewpoint of avoiding electric field coupling between the ground conductor 102 and the coupling electrode 108, the height from the circuit mounting surface of the printed circuit board 101 to the coupling electrode 108 is important.

  For example, as shown in FIG. 19, a coupling electrode 108 is disposed on the upper surface of a spacer 109 having an appropriate height, and is connected to the central portion of the stub 103 via a through hole 110 penetrating the spacer 109. It is configured as follows. The spacer 109 is made of an insulator and has a role of supporting the coupling electrode 108 at a desired height. After a through hole is formed in a columnar dielectric having a desired height, a conductor 109 is filled in the through hole, and a conductor pattern to be a coupling electrode is deposited on the upper end surface, thereby producing a spacer 109. can do. The spacer 109 on which the coupling electrode is formed is mounted on the printed circuit board 101 by a process such as reflow soldering.

  FIG. 20 shows a state in which the spacer 109 in which the coupling electrode 108 and the through hole 109 as the metal wire are formed is mounted on the printed circuit board 101 as a surface mount component.

  In the illustrated example, the coupling electrode 108 and the folded stub 103 are formed on the upper and lower surfaces of the spacer 109 made of an insulator. For example, after a through hole is formed in a columnar dielectric having a desired height, the conductor is filled in the through hole, and the conductor pattern of the coupling electrode 108 and the stub 103 is formed on the upper and lower sides of the dielectric by a plating technique. The spacer 109 can be manufactured by vapor-depositing on each end face. At this time, the coupling electrode 108 on the upper end surface is connected to the central portion of the stub 103 on the lower end surface side through a through hole 110 penetrating the spacer 109.

  On the printed circuit board 101, conductor patterns 111 and 112 such as a microstrip line or a coplanar waveguide that are joined to both ends of the spacer 109 are formed. One conductor pattern 111 is a signal line drawn from the transmission / reception circuit module 105, and the other conductor pattern 112 is connected to the ground conductor 102 through a through hole 106 that penetrates the printed circuit board 101. The spacer 109 on which the coupling electrode and the folded stub are formed is mounted on the printed circuit board 101 by a process such as reflow soldering.

  In the example shown in FIG. 20, the coupling electrode 108 and the stub 103 are deposited on the upper end surface and the lower end surface of the spacer 109 respectively. As a modification, only the coupling electrode 108 is deposited on the spacer 109. The stub 103 is formed as a microstrip line or a coplanar waveguide on the printed circuit board 101 so that when the spacer 109 is surface-mounted, the coupling electrode 108 and the stub 103 are connected through the through hole 110 in the spacer 109. It can also be configured.

  In the configuration example of the high frequency coupler shown in FIGS. 19 and 20, the spacer 109 is made of an insulator (described above). However, when a material having a high dielectric constant is used, the wavelength is substantially reduced due to the wavelength shortening effect. Therefore, the dimensions of the stub 103 and the coupling electrode 108 can be reduced.

  The high-frequency coupler shown in FIG. 18 has a problem in that the coupling electrode is supported by a single metal wire at the approximate center, and the mechanical strength is not sufficient. On the other hand, in the high-frequency coupler shown in FIG. 19 or 20, a dielectric is provided between the coupling electrode and the printed circuit board provided with the resonance stub in order to fix the coupling electrode and increase the mechanical strength. The spacer which consists of is arrange | positioned. Also in the latter high-frequency coupler, the resonance stub is composed of a “short stub” having a length that is approximately one half of the wavelength λ of the resonance frequency, with its tip short-circuited, and a metal wire at approximately the center thereof. A coupling electrode is connected.

  However, in the high-frequency coupler shown in FIG. 19 or FIG. 20, the arrangement of the spacer increases the component cost and the apparatus weight. In addition, the dielectric loss inside the spacer causes a problem that the propagation loss deteriorates (dielectrics have a delay caused by a change in the high-frequency electric field caused by a dipole that provides dielectric properties, or a current in phase with the electric field flows, causing electromagnetic waves to flow. Dielectric loss is caused by converting energy into heat, and generation of an electric field is suppressed at that time).

  On the other hand, in the configuration in which the spacer is not disposed, since the electrical characteristics are not deteriorated due to dielectric loss, the characteristics as a high-frequency coupler are excellent. However, as shown in FIG. The structure of supporting it is not enough for mechanical strength and is not suitable for mass production.

  Therefore, the present inventors have provided a plurality of metal wires supporting the coupling electrode on the resonance stub, so that sufficient mechanical strength can be ensured without a spacer, and electrical characteristics can be obtained by not interposing a spacer. Removed the factors that make it worse.

  Here, the difference in electrical characteristics between the case where the coupling electrode is connected to the resonance stub with one metal wire and the case where the coupling electrode is supported with two metal wires will be considered. FIG. 21 shows a high-frequency coupler in which the coupling electrode is supported by a spacer made of a dielectric, and the coupling electrode is connected to the resonance stub by one metal wire penetrating the through hole of the spacer. A cross-sectional configuration is shown. FIG. 22 shows a cross-sectional configuration of a high-frequency coupler in which a coupling electrode is supported by two metal wires on a resonance stub.

  The current input from the transmission / reception circuit section through the signal line flows toward the ground through the resonance stub and the through hole at the tip, and at that time, more current is coupled via the metal line. When flowing into the electrode side, it is considered that the transmission signal intensity of the high-frequency coupler increases. As a result of the experiment, the two metal wires from the resonance stub in FIG. 22 are larger than the current (arrows 1 and 2 in FIG. 21) flowing from the resonance stub into the coupling electrode through one metal wire in FIG. It was found that the current (arrows 4 and 5 in the figure) flowing into the coupling electrode through the electrode becomes smaller. This is because by using two metal wires connecting the coupling electrode to the resonance stub, the current passing through the resonance stub without flowing into the coupling electrode (arrow 6 in FIG. 22) This is because the current increases more than the current passing through the resonance stub when there is one line (arrow 3 in FIG. 22). As a result, the current hardly flows to the coupling electrode side, and the efficiency of the high-frequency coupler is reduced. Getting worse.

  Therefore, as shown in FIG. 23, in order to suppress the current passing through the resonance stub without flowing through the coupling electrode, the resonance stub is cut and the metal wires before and after supporting the coupling electrode are connected to each other. It was made to connect to the resonance stub so as to straddle the cut portion. Hereinafter, the distal end side of the cut resonance stub is referred to as a “first resonance stub”, and the input end side of the other signal line is referred to as a “second resonance stub”.

  According to the configuration shown in FIG. 23, in order for the current input from the transmission / reception circuit section to flow through the signal line toward the tip of the resonance stub, one side is once shown as shown by the arrow 7 in FIG. After flowing into the coupling electrode via the metal wire, as shown by the arrow 8 in the figure, it flows into the resonance stub after the cut portion via the other metal wire. That is, as shown by the arrow 6 in FIG. 22, there is no current component flowing through the resonance stub through the coupling electrode. Therefore, if the amount of current indicated by the arrows 7 and 8 in FIG. The characteristics of the coupler are improved.

  Next, consider the attachment position of the coupling electrode or the cutting position of the resonance stub.

  A signal input from the transmission / reception circuit via the signal line is reflected at the tip of the resonance stub, and a standing wave is generated in the resonance stub. As already described with reference to FIG. 12, the position of the voltage standing wave is large (ie, the position of the “antinode” of the voltage standing wave) without connecting the coupling electrode via the metal wire. By connecting the coupling electrode, the electrical characteristics of the high-frequency coupler can be improved.

  As described above, in the high-frequency coupler having a configuration in which the resonance stub is cut and the two metal wires before and after supporting the coupling electrode are connected to the resonance stub across the cut portion, Similarly, it is desirable that the coupling electrode is disposed near a position where the amplitude of the voltage standing wave is large.

  Here, a ground is formed on the other surface of the printed circuit board on which the high-frequency coupler is mounted. The front end portion of the resonance stub may be an open end, or may be connected to the ground via a through hole in the printed circuit board to be a short-circuit end. However, standing of the standing wave differs depending on whether the leading end portion of the resonance stub, that is, the first resonance stub is the open end or the short-circuit end, and the position where the amplitude of the voltage standing wave is large, that is, the coupling electrode The appropriate position for mounting is different.

  FIG. 24 shows the respective amplitudes of the voltage standing wave and the current standing wave inside the resonance stub when the first resonance stub is at the open end. In this case, as shown in the figure, a voltage standing wave is generated at each of the open end on the first resonance stub side and the input end on the second resonance stub side, and the current standing wave is Has a phase difference of π / 4 with respect to a large voltage standing wave. Therefore, if the total length of the resonance stub, the metal wire, and the coupling electrode is about 360 degrees as the phase length of the resonance frequency as shown in the figure, the amplitude of the voltage standing wave is large at about the center. Therefore, it is preferable to cut the resonance stub into the first and second resonance stubs at approximately the center, and attach the coupling electrode so that the cut portion is connected by two metal wires.

  FIG. 25 shows the amplitudes of the voltage standing wave and current standing wave inside the resonance stub when the first resonance stub is short-circuited. In this case, as shown in the figure, the voltage standing wave has an amplitude of 0 at the short-circuited end on the first resonance stub side and a voltage constant that maximizes at each of the input ends on the second resonance stub side. A standing wave stands and the current standing wave has a phase difference of π / 4 with respect to such a voltage standing wave. Therefore, if the total length of the resonance stub, the metal wire, and the coupling electrode is about 270 degrees as the phase length of the resonance frequency as shown in the drawing, it is 3 minutes before the tip of the first resonance stub. Since the amplitude of the voltage standing wave becomes large at the position 1 (or the position two thirds from the input end), the resonance stub is cut into the first and second resonance stubs at the position, and It is preferable to attach a coupling electrode so that the cut portion is connected by two metal wires. Actually, in consideration of the phase transition inside the metal wire and the coupling electrode, the first and second positions at a predetermined position that is slightly closer to the front end than a third from the short-circuited end of the first resonance stub. It is preferable to provide a cutting part that divides the second resonance stub.

  It should be well understood that in both configurations of FIGS. 24 and 25, the amount of charge on the coupling electrode is large and the electrical characteristics of the high frequency coupler are good.

  Further, when the coupling electrode is supported by a single metal wire, there is a concern that an unnecessary radio wave is generated due to current flowing through the metal wire. On the other hand, when the coupling electrode is supported by two metal wires, the currents cancel each other if the coupling electrodes are installed at positions where currents flowing in opposite directions flow in the respective metal wires. In combination, unnecessary radio wave radiation can be reduced.

  In an electric field coupling type non-contact communication system that is coupled by an electrostatic field or an induction electric field as described above, if a high frequency coupler is ideally designed, generation of unnecessary radio waves is suppressed when coupled with a communication partner. It is possible to prevent the reception of external radio waves. However, the high-frequency coupler has a high impedance in a no-load state that is not coupled with the communication partner, so that there is a problem that a reflected wave is generated in the coupling electrode serving as a termination and a standing wave is generated in the circuit. . When the signal line or the ground operates like an antenna due to the standing wave, unnecessary radio waves may be radiated to affect external electronic devices.

  FIG. 11 shows a high-frequency coupler in which an impedance matching portion and a resonance portion are formed by stubs to achieve a wide band. When the high frequency coupler is in a load state, that is, when the high frequency coupler on the communication counterpart side is in a close position, impedance matching is achieved as described above, and the transmission signal is efficiently radiated. On the other hand, when there is no load, that is, when the high frequency coupler on the communication partner side does not exist in the close position, the entrance portion of the high frequency coupler (the start point of the pattern to be a stub shown by the point A in FIG. 11) is Since it is in a high impedance state, the transmission signal flowing in from the circuit part is reflected at this entrance part and returns to the transmission circuit side.

  As shown in FIG. 26, a standing wave is generated when a wave traveling in the circuit and a wave reflected in the opposite direction simultaneously exist. In general, it is known that standing waves become a source of unnecessary radio noise. Also, the RF filter (not shown) in the transmission / reception circuit is usually designed so that its performance can be exhibited when both the input and output sides are 50 Ω, that is, when impedance matching is achieved and there is no reflected wave. However, if there is a reflected wave, normal operation is hindered, and spurious may occur or the signal may be distorted.

  Therefore, the communication device according to the present invention has a high-frequency coupler that has a large impedance in an unloaded state, in addition to configuring the impedance matching section and the resonance section of the high-frequency coupler by a distributed constant circuit to increase the bandwidth. It can be regarded as the end, and has a load resistance to suppress the reflected wave from the end of the high-frequency coupler that occurs in the no-load state. As a result, the high-frequency coupler side when viewed from the transmission / reception circuit side The impedance matching can be achieved.

  In such a case, impedance matching is achieved when viewed from the transmission / reception circuit side even in a no-load state where the high-frequency couplers are not close to each other, and no reflected wave is generated at the terminal electrode. The wave can be suppressed. As a result, unnecessary radio wave radiation is suppressed and the influence on external electronic devices is small. Further, it is possible to suppress the occurrence of signal distortion and spurious due to the normal operation of the RF filter and the like.

  FIG. 27 shows the configuration of an equivalent circuit of a high-frequency coupler having a load resistor connected to the input end. As shown in the figure, when a load resistor is connected to the input end of the high frequency coupler, when the high frequency coupler on the communication partner side is not in a close position, the terminal is simply grounded via the load resistor. Since the signal flowing in through the line is consumed by the load resistance, no reflected wave is generated. At this time, when viewed from the transmission / reception circuit side, the high-frequency coupler is matched to 50Ω, so that the transmission signal is not reflected by the high-frequency coupler, and unnecessary radio waves are generated from standing waves in the circuit. This can prevent the characteristics of the RF filter and the like from deviating from the design.

  Further, FIG. 28 shows two metal wires that are cut into two, ie, the first resonance stub on the front end side and the second resonance stub on the input end side as described above, and support the coupling electrode. The state where the load resistance is attached to the input end of the high frequency coupler to which the coupling electrode is attached so as to straddle the cut portion is shown.

  In the illustrated example, the resonance stub is an open end, and a voltage standing wave that is maximum at each of the open end on the first resonance stub side and the input end on the second resonance stub side is generated, The current standing wave has a phase difference of π / 4 with respect to such a voltage standing wave. Then, if the length of the entire resonance stub is approximately 360 degrees as the phase length of the resonance frequency, the amplitude of the voltage standing wave increases substantially at the center thereof. When there is no communication partner nearby, the signal reflected in the high frequency coupler is consumed by the load resistance and does not affect the subsequent circuits. The load resistance is preferably connected to a position where the voltage amplitude becomes maximum, such as the input end of the resonance stub.

  Here, in the communication method using the electric field coupling by the electrostatic field or the induction electric field, in order to generate the electric field coupling between the coupling electrodes, it is necessary to delicately align the coupling electrodes between the transceivers. However, it is often difficult for the user to know in which part of the device the coupling electrode is arranged and which part should be contacted, and thus there is a possibility that the maximum communication speed cannot be obtained. As a solution to this type of problem, a configuration in which a plurality of high frequency couplers are arranged in a single transceiver can be considered.

  In the case of radio wave communication, if multiple transmission antennas are provided in parallel, the transmission power is distributed to each antenna and the output of each antenna is reduced, so antennas that do not contribute to communication waste transmission power. End up. On the other hand, in the communication system using electric field coupling, only those having a coupling relationship with other high-frequency couplers can transmit high-frequency signals, and other high-frequency couplers can be designed to be regarded as almost open ends. . That is, even if a plurality of high-frequency couplers are arranged in an array, for example, the problem that a high-frequency coupler that does not perform electric field coupling with the high-frequency coupler on the communication partner side wastes transmission power is not serious.

  FIG. 29 shows an example in which a plurality of (two in the illustrated example) high-frequency couplers are connected in parallel to one signal line connected to the transmission / reception circuit unit. At this time, it is configured so that the no-load high-frequency coupler is handled as an open end, in other words, the high-frequency couplers are connected so that each high-frequency coupler branches at a position where the amplitude of the voltage standing wave at the time of no load increases. Is the most efficient. For this purpose, as shown in the figure, when the tip of the first resonance stub is an open end, the signal line is located at a position where the length from the tip is an integral multiple of one-half wavelength of the resonance frequency. It is good to comprise so that it may be connected to.

  The high-frequency coupler as shown in FIG. 24 or FIG. 25 can control the propagation loss and the specific band according to the width of the resonance stub. That is, the voltage amplitude is maximized at the position where the second resonance stub is connected to the signal line, and at the same time, by changing the width of the resonance stub (that is, the impedance of the resonance stub), Impedance conversion is performed by the stub, and the amount of current flowing through the coupling electrode can be controlled. Here, as shown in FIG. 24, the propagation loss and the specific band are measured when the high frequency couplers having the first resonance stubs configured as open ends are arranged facing each other as shown in FIG. I tried to.

Here, the propagation loss refers to the insertion loss when one high frequency coupler is connected to port 1 of the network analyzer and the other high frequency coupler is connected to port 2, that is, the value of the S parameter (S ₂₁ ). That is. The ratio band refers to the ratio of the frequency range in which the amount of decrease in the value of S ₂₁ is within 3 dB to the value of the propagation loss S ₂₁ at the resonance frequency with respect to the resonance frequency. In the measurement, the distance between the coupling electrodes is 20 mm, the size of the coupling electrode of each high-frequency coupler is 10 mm × 10 mm, the height is 3 mm, and the lengths of the first resonance stub and the second resonance stub are respectively The widths of the first and second resonance stubs were changed under the conditions of 16 mm, the dielectric constant of the substrate was 3.4, and the thickness was 0.8 mm.

  FIG. 31A and FIG. 31B show the measurement results of the propagation loss and the specific band at this time, respectively. From each figure, there is little loss when the stub width is large. It can also be seen that the smaller the stub width, the wider the specific bandwidth.

  Further, the coupling electrode of the high-frequency coupler can be easily and inexpensively manufactured by integrally forming with two metal wires by, for example, sheet metal processing. As the sheet metal, for example, a phosphor bronze sheet whose surface is plated with gold can be used. 32 and 33 illustrate the manufacturing method.

  In each figure, a sheet metal made of a phosphor bronze plate or the like is first punched to form a portion to be a coupling electrode and a portion to be two metal wires for connecting the coupling electrode and the high-frequency signal line. .

  Subsequently, the punched sheet metal is subjected to a bending process, and a leg portion serving as a metal wire is bent substantially perpendicularly to the coupling electrode portion to form a desired height. The desired height referred to here corresponds to a dimension capable of having a role of avoiding coupling between the coupling electrode portion and the ground and a role of the leg portion forming a series inductor.

  The coupling electrode thus completed is positioned such that the cut portion of the first and second resonance stubs straddles the two legs at a corresponding location on the printed circuit board, for example, and a jig (not shown) ) Etc. and then attached by reflow soldering. FIG. 34 shows a state where the coupling electrode shown in FIG. 32 is attached to a resonance stub formed as a microstrip line or a coplanar waveguide on a printed board.

  34 does not depict the transmission / reception circuit unit, it may be provided on the same substrate, or may be provided on a separate substrate via a high-frequency connector or a coaxial cable, respectively, at the optimum position of the radio. It may be placed apart.

So far, a mechanism for transmitting signals between a pair of high-frequency couplers in an electric field coupling type non-contact communication system has been described. Here, when a signal is transmitted between two devices, energy transfer is inevitably involved. Therefore, this type of communication system can be applied to power transmission. As described above, the electric field E _R generated by the EFC antenna of the transmitter is the air propagates as a surface wave, power can be taken out by rectifying and stabilizing a signal received by the EFC at the receiver .

  FIG. 35 shows a configuration example when a communication system using a high-frequency coupler is applied to power transmission.

  In the illustrated system, a charger connected to an AC power source and a wireless communication device are brought close to each other, so that power is transmitted and charged to the wireless communication device in a non-contact manner via a high-frequency coupler built in them. However, the high frequency coupler is used only for power transmission.

  When the receiving high-frequency coupler is not near the transmitting high-frequency coupler, most of the power input to the transmitting high-frequency coupler is reflected and returns to the DC / AC inverter side. Radiation can be suppressed.

  Moreover, although the example which performs charge to a radio | wireless communication apparatus was given in the figure, you may make it perform the non-contact electric power transmission not only to a radio | wireless machine but the music player or a digital camera, for example.

  FIG. 36 shows another configuration example in which a communication system using a high-frequency coupler is applied to power transmission. The illustrated system is configured to use a high-frequency coupler and a surface wave transmission line for both power transmission and communication.

  Switching of timing for performing communication and power transmission is performed by a communication / transmission (reception) switching signal sent from the transmission circuit unit. For example, communication and power transmission may be switched at a predetermined cycle. At this time, the power transmission output can be kept optimal by adding the charging state to the communication signal and feeding back to the charger side. For example, when charging is completed, the information may be sent to the charger side, and the power transmission output may be set to zero.

  In the system shown in the figure, the charger is connected to an AC power supply. However, for example, the battery can be used to distribute power from another mobile phone to a mobile phone with a low battery. It may be used.

  The present invention has been described in detail above with reference to specific embodiments. However, it is obvious that those skilled in the art can make modifications and substitutions of the embodiment without departing from the gist of the present invention.

  In the present specification, the embodiment applied to a communication system in which a UWB signal is data-transmitted by electric field coupling in a cableless manner has been mainly described, but the gist of the present invention is not limited to this. For example, the present invention can be similarly applied to a communication system that uses a high-frequency signal other than the UWB communication method and a communication system that performs data transmission by electric field coupling using a relatively low frequency signal.

  In the present specification, the embodiment in which the present invention is applied to a system that performs data communication between a pair of high-frequency couplers has been mainly described. However, when a signal is transmitted between two devices, it is inevitable. It is naturally possible to apply this type of communication system to power transmission because it involves energy transfer.

  In short, the present invention has been disclosed in the form of exemplification, and the description of the present specification should not be interpreted in a limited manner. In order to determine the gist of the present invention, the claims should be taken into consideration.

FIG. 1 is a diagram illustrating a configuration example of a non-contact communication system using electric field coupling by an electrostatic field or an induction electric field. FIG. 2 is a diagram showing a configuration example in which a transmitter and a receiver include a coupler composed only of electrodes in a communication using frequencies in the kHz or MHz band, and the coupling portion simply operates as a parallel plate capacitor. . FIG. 3 is a diagram illustrating a state in which a propagation loss occurs due to reflection of a signal in an impedance mismatching portion in a coupling portion in communication using a high frequency in the GHz band. FIG. 4 is a diagram showing an equivalent circuit of a high-frequency coupling circuit in which an impedance matching unit and a resonance unit are configured by a lumped constant circuit. FIG. 5 is a diagram illustrating a state in which the electrodes of the high-frequency coupler illustrated in FIG. 4 are arranged to face each other. FIG. 6A is a diagram for explaining the characteristics of the high-frequency coupler shown in FIG. 4 alone. FIG. 6B is a diagram for explaining the characteristics of the high-frequency coupler shown in FIG. 4 alone. FIG. 7A is a diagram illustrating a state in which the high frequency coupler induces an electric field by the function as an impedance converter. FIG. 7B is a diagram illustrating a state in which the high frequency coupler induces an electric field by the function as an impedance converter. FIG. 8 is a diagram showing an equivalent circuit of a bandpass filter configured by arranging the two high-frequency couplers shown in FIG. 4 to face each other. FIG. 9 is a diagram showing an equivalent circuit of an impedance conversion circuit configured as a single high-frequency coupler. FIG. 10 is a diagram showing an electromagnetic field generated by a minute dipole. FIG. 11 is a diagram illustrating a configuration example of a high-frequency coupler using a distributed constant circuit for the impedance matching unit and the resonance unit. FIG. 12 is a diagram illustrating a state in which a standing wave is generated in the stub 103. FIG. 13 is a diagram showing a comparison of the frequency characteristics of the high-frequency coupler when the impedance matching unit is composed of a lumped constant circuit and a distributed constant circuit. FIG. 14 is a diagram illustrating a high-frequency coupler in which an impedance matching unit is configured by a lumped constant circuit. FIG. 15 is a diagram illustrating a high-frequency coupler in which an impedance matching unit is configured by a distributed constant circuit. FIG. 16A is a diagram illustrating a state in which a high-frequency transmission line is connected to the center of the coupling electrode. FIG. 16B is a diagram illustrating a state in which a high-frequency transmission line is connected to a position having an offset from the center of the coupling electrode, and an unequal current flows in the conclusion electrode. FIG. 17 is a diagram showing a configuration example of a “capacitance loaded type” antenna in which a metal is attached to the tip of the antenna element to give a capacitance and the height of the antenna is shortened. FIG. 18 is a view showing a high-frequency coupler in which the stub 103 is bent under the coupling electrode 108. FIG. 19 is a diagram showing a state in which the coupling electrode 108 is supported using the spacer 109. FIG. 20 is a diagram illustrating an example in which the spacer 109 is configured as a surface-mounted component of the printed circuit board 101. FIG. 21 shows a cross section of a high-frequency coupler in which the coupling electrode is supported by a spacer made of a dielectric, and the coupling electrode is connected to the resonance stub by one metal wire penetrating the through hole of the spacer. It is the figure which showed the structure. FIG. 22 is a diagram showing a cross-sectional configuration of a high-frequency coupler in which a coupling electrode is supported by two metal wires on a resonance stub. FIG. 23 is a diagram showing a cross-sectional configuration of a high-frequency coupler in which a resonance stub is cut and metal wires before and after supporting a coupling electrode are connected to the resonance stub so as to straddle the cut portion. FIG. 24 is a diagram illustrating the amplitudes of the voltage standing wave and the current standing wave when the first resonance stub is at the open end. FIG. 25 is a diagram illustrating amplitudes of the voltage standing wave and the current standing wave when the first resonance stub is the short-circuited end. FIG. 26 is a diagram illustrating a state in which a standing wave is generated when a wave traveling in the circuit and a wave reflected in the opposite direction simultaneously exist. FIG. 27 is a diagram showing a configuration of an equivalent circuit of a high-frequency coupler having a load resistor connected to the input end. In FIG. 28, the first resonance stub on the front end side and the second resonance stub on the input end side are cut into two, and the cut portion is crossed by two metal wires supporting the coupling electrode. It is the figure which showed a mode that the load resistance was attached to the input terminal of the high frequency coupler with which the electrode for coupling | bonding was attached. FIG. 29 is a diagram illustrating an example in which a plurality of high frequency couplers are connected in parallel to one signal line connected to the transmission / reception circuit unit. FIG. 30 is a diagram illustrating a state in which the high-frequency couplers illustrated in FIG. 24 are arranged to face each other. FIG. 31A is a diagram showing a propagation loss measured when two high-frequency couplers are arranged to face each other as shown in FIG. FIG. 31B is a diagram showing a ratio band measured when two high-frequency couplers are arranged to face each other as shown in FIG. FIG. 32 is a diagram showing an example of a coupling electrode manufactured by sheet metal processing. FIG. 33 is a diagram showing an example of a coupling electrode manufactured by sheet metal processing. FIG. 34 is a diagram illustrating a state in which the coupling electrode illustrated in FIG. 32 is attached to the resonance stub on the printed circuit board. FIG. 35 is a diagram illustrating a configuration example when a communication system using a high-frequency coupler is applied to power transmission. FIG. 36 is a diagram showing another configuration example in which a communication system using a high-frequency coupler is applied to power transmission.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 ... Printed circuit board 102 ... Ground 103 ... Stub 104 ... Signal line 105 ... Transmission / reception circuit 106 ... Through hole 107 ... Metal wire 108 ... Coupling electrode 109 ... Spacer 110 ... Through hole 111, 112 ... Microstrip line or coplanar waveguide

Claims (3)

  A high-frequency coupler comprising a coupling electrode, a resonance part for strengthening electrical coupling between the coupling electrodes, and first and second metal wires that support the coupling electrode with respect to the resonance part . A high-frequency signal transmission line is connected, and a coupling electrode and a ground arranged to form an electric dipole;
A resonance unit for generating a stronger electric field by increasing a current flowing into the coupling electrode;
Comprising
Generating a longitudinal wave of an electric field oscillating in a direction parallel to a propagation direction in the direction of the coupling electrode as viewed from the ground by the electric dipole, and emitting the high-frequency signal to a communication partner side by the longitudinal wave of the electric field;
The high frequency coupler according to claim 1. An electric field signal radiating element comprising a coupling electrode used in a high-frequency coupler and first and second metal wires supporting the coupling electrode.