JP2012065104A - Antenna device and communication apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna device having a structure advantageous for downsizing a coupling electrode while enabling both excellent communication property and mechanical strength to be achieved.SOLUTION: The antenna device comprises a coupling electrode 18 including wiring 12a, 12b respectively formed on both faces 11a, 11b of a dielectric substrate 11 with one ends connected with each other via a connection through hole 14a, and electromagnetically coupled to an electrode of another antenna device disposed at a position facing the own antenna device to be communicable with the other antenna device. The wiring 12a, 12b connected with each other via the connection through hole 14a has a length approximately the same as a communication wavelength. Positions at a distance of 1/4 of the communication wavelength from respective end parts of the wiring 12a, 12b not connected to the connection through hole 14a are facing each other across the dielectric substrate 11.

Description

  The present invention relates to an antenna device that performs information communication by electromagnetic field coupling between a pair of electrodes facing each other at a predetermined communication wavelength, and a communication device in which the antenna device is incorporated.

  In recent years, a system has been developed in which data such as music and images is transmitted wirelessly between electronic devices such as computers and small portable terminals without using cables or media. Some of such wireless transmission systems are capable of high-speed transfer of up to about 560 Mbps at a short distance of several centimeters. Among such transmission systems capable of high-speed transfer, TransferJet (registered trademark) is advantageous in that the communication distance is short but the possibility of eavesdropping is low and the transmission speed is high.

  TransferJet (registered trademark) can be achieved by electromagnetic field coupling of corresponding high frequency couplers at very short distances, and the signal quality depends on the performance of the high frequency coupler. For example, as shown in FIG. 14, a high-frequency coupler described in Patent Document 1 has a printed circuit board 201 in which a ground 202 is formed on one surface and a microstrip structure formed on the other surface of the printed circuit board 201. The stub 203 includes a coupling electrode 208 and a metal wire 207 that connects the coupling electrode 208 and the stub 203. In the high frequency coupler described in Patent Document 1, a transmission / reception circuit 205 is also formed on the printed circuit board 201. Further, in Patent Document 1, as a modified example in which the transmission / reception circuit 205 is not formed on the printed circuit board 201, a printed circuit board 201 in which a ground 202 is formed on one surface as shown in FIG. A configuration including a microstrip structure stub 203 formed on the other surface, a coupling electrode 208, and a metal wire 207 connecting the coupling electrode 208 and the stub 203 is described.

JP 2008-31816 A

  However, as shown in FIG. 14, the high-frequency coupler described in Patent Document 1 needs to increase the area of the plate-like coupling electrode 208 in order to perform good communication. This is because a certain length depending on the communication wavelength is necessary, and in order to increase the coupling strength, the coupling electrode 208 must be enlarged. In addition, since the metal wire 207 needs to connect the coupling electrode 208 and the stub 203 at a predetermined position, there is a problem in process such that alignment accuracy is required at the time of manufacture.

  The present invention has been proposed in view of such circumstances, and an antenna device having a structure advantageous for downsizing of a coupling electrode while realizing both good communication characteristics and mechanical strength can be realized. The purpose is to provide. Another object of the present invention is to provide a communication device in which this antenna device is incorporated.

  As a means for solving the above-described problem, an antenna device according to the present invention is an antenna device that performs information communication by electromagnetic coupling between a pair of electrodes facing each other at a predetermined communication wavelength. One end of the wiring formed on both sides of the substrate is connected through a through hole, and is provided with a coupling electrode that is electromagnetically coupled to an electrode of another antenna device disposed at an opposite position so that communication is possible. The wiring connected through the hole has a wiring length that is substantially the same as the communication wavelength, and each position that is a quarter of the communication wavelength away from the end of the wiring that is not connected to the through-hole, Opposing each other across the dielectric substrate.

  The communication device according to the present invention is a communication device that performs information communication by electromagnetic coupling between electrodes of other communication devices arranged at opposite positions at a predetermined communication wavelength, and includes a dielectric substrate One end of the wiring formed on both sides is connected through a through-hole, and connected to the through-hole through a coupling electrode that can be electromagnetically coupled to an electrode of another antenna device arranged at the opposite position and communicated And a transmission / reception processing unit for performing signal transmission / reception processing, which is electrically connected via a connection terminal formed at an end of the wiring that is not connected, and the wiring connected through the through hole has its wiring length However, the length is substantially the same as the communication wavelength, and the respective positions separated from the connection terminal by a quarter of the communication wavelength are opposed to each other with the dielectric substrate interposed therebetween.

  In the present invention, the coupling electrode is connected to one end of the wiring formed on both surfaces of the dielectric substrate through the through-holes, thereby realizing good mechanical strength and downsizing of the entire antenna device. can do. Further, according to the present invention, each position that is 1/4 of the communication wavelength from the end of the wiring that is not connected to the through hole is opposed to each other with the dielectric substrate interposed therebetween. Coupling with other coupling electrodes arranged at opposite positions by efficiently emitting a longitudinal wave of an electric field in the thickness direction of the substrate by having a high signal level with opposite polarities The strength is increased and good communication characteristics can be realized.

  As described above, according to the present invention, it is possible to reduce the size of the entire apparatus while realizing both good communication characteristics and mechanical strength.

It is a figure which shows the structure of the communication system with which the antenna device to which this invention was applied is integrated. It is a figure which shows the structure of the high frequency coupler which concerns on 1st Embodiment which is an antenna device to which this invention was applied. It is a perspective view which shows the communication state between high frequency couplers in the high frequency coupler which concerns on 1st Embodiment. It is an electric field distribution map which shows the electric field analysis result in the central section in the high frequency coupler concerning a 1st embodiment. It is an electric field distribution diagram which shows the electric field analysis result in 1 mm on the electrode surface of the high frequency coupler concerning a 1st embodiment. It is a frequency characteristic figure which shows the analysis result of the coupling strength between the high frequency coupler concerning a 1st embodiment, and a standard coupler. It is a figure which shows the structure of the high frequency coupler which concerns on 2nd Embodiment which is an antenna apparatus with which this invention was applied. It is a figure which shows the structure of the high frequency coupler which concerns on 2nd Embodiment which is an antenna apparatus with which this invention was applied. It is a perspective view which shows the communication state between high frequency couplers in the high frequency coupler which concerns on 2nd Embodiment. It is a perspective view which shows the analysis cross section of the electric field vector in the high frequency coupler which concerns on 2nd Embodiment. It is an electric field distribution map which shows the electric field analysis result in the central section in the high frequency coupler concerning a 2nd embodiment. It is an electric field distribution diagram which shows the electric field analysis result in 1 mm on the electrode surface of the high frequency coupler concerning a 2nd embodiment. It is a frequency characteristic figure which shows the analysis result of the coupling strength between the high frequency coupler concerning a 2nd embodiment, and a standard coupler. It is a figure which shows the structure of the high frequency coupler which concerns on a prior art example. It is a figure which shows the structure of the high frequency coupler which concerns on a prior art example.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. It should be noted that the present invention is not limited to the following embodiments, and various modifications can be made without departing from the scope of the present invention.

<Communication system>
An antenna device to which the present invention is applied is a device that performs information communication by electromagnetic coupling between a pair of opposed electrodes, and is a communication system that enables high-speed transfer of about 560 Mbps, for example, as shown in FIG. 100 is used by being incorporated.

  The communication system 100 includes communication devices 101 and 105 that perform two data communications. Here, the communication apparatus 101 includes a high-frequency coupler 102 having a coupling electrode 103 and a transmission / reception circuit unit 104. In addition, the communication device 105 includes a high-frequency coupler 106 having a coupling electrode 107 and a transmission / reception circuit unit 108.

  As shown in FIG. 1, when the high-frequency couplers 102 and 106 provided in each of the communication devices 101 and 105 are arranged to face each other, the two coupling electrodes 103 and 107 operate as one capacitor, and the band-pass filter as a whole. By operating in this way, a high-frequency signal in the 4 to 5 GHz band for realizing high-speed transfer of, for example, about 560 Mbps can be efficiently transmitted between the two high-frequency couplers 102 and 106.

  Here, the transmitting and receiving coupling electrodes 103 and 107 included in the high-frequency couplers 102 and 106 are arranged to face each other with a distance of, for example, about 3 cm, and can be coupled to each other.

  In the communication system 100, for example, the transmission / reception circuit unit 104 connected to the high-frequency coupler 102 generates a high-frequency transmission signal based on the transmission data when a transmission request is generated from a higher-level application, and the coupling electrode 103 generates a coupling electrode. The signal is propagated to 107. Then, the transmission / reception circuit unit 108 connected to the reception-side high-frequency coupler 106 demodulates and decodes the received high-frequency signal, and passes the reproduced data to the higher-level application.

  The antenna device to which the present invention is applied is not limited to the above-described one that transmits a high frequency signal in the 4 to 5 GHz band, and can be applied to signal transmission in other frequency bands. A high frequency signal in the 4 to 5 GHz band will be described as a transmission target.

<First Embodiment>
As an antenna device incorporated in such a communication system 100, a high-frequency coupler 1 according to the first embodiment as shown in FIG. 2 will be described.

  In FIG. 2, the dielectric substrate 11 is shown in a transparent manner for easy understanding of the connection state of the wirings 12 a and 12 b.

  As shown in FIG. 2, the high-frequency coupler 1 includes wirings 12a and 12b each having a plurality of folded portions on the upper and lower surfaces 11a and 11b of the dielectric substrate 11, that is, so-called ninety-nine folds or meanders. The structure is formed. One end of each of the meander-shaped wirings 12a and 12b is electrically connected via a connection through hole 14a formed in the thickness direction of the dielectric substrate 11, and is connected to another antenna device disposed at an opposing position. It functions as a coupling electrode 18 that is electromagnetically coupled to the electrode and can communicate.

  The coupling electrode 18 includes an end 19a of the wiring 12a that is not connected to the connecting through hole 14a and the other end of the wiring 12b that is not connected to the connecting through hole 14a. A connecting terminal portion 19 is formed on the same surface 11b. The connecting terminal portion 19 includes an end portion 19b extending to the surface 11b.

  The connection terminal portion 19 is a terminal for connection with the above-described transmission / reception circuit portion 104. For example, the connection terminal portion 19 is connected by a flexible printed board via an anisotropic conductive film, or by a thin coaxial cable via a surface mount receptacle. It becomes connection means such as connection. For this reason, the shape of the connection terminal portion 19 is adjusted, and depending on the connection method, the connection through hole 14b is omitted, and the end portions 19a and 19b are arranged on both surfaces of the dielectric substrate 11, respectively. The configuration described above may be adopted.

  The coupling electrode 18 is configured by connecting meander-shaped wirings 12a and 12b formed on both surfaces of the dielectric substrate 11, and is a wiring length connecting the wirings 12a and 12b, that is, a coupling electrode. The length of 18 is adjusted to be approximately one wavelength of the communication frequency. Furthermore, the coupling electrode 18 is opposed to the end of the wirings 12a and 12b that are not connected to the connection through hole 14a by a distance of 1/4 of the communication wavelength from the ends 19a and 19b with the dielectric substrate 11 in between. ing.

  As a specific example, in the coupling electrode 18, the positions apart from the ends 19 a and 19 b of the wirings 12 a and 12 b that are not connected to the connection through-hole 14 a by ¼ of the communication wavelength are the center portions of the surfaces 11 a and 11 b, respectively. 15a and 15b.

  In this way, in the coupling electrode 18, as is apparent from the following evaluation, the center is separated from the ends 19 a and 19 b of the wirings 12 a and 12 b not connected to the connection through-hole 14 a by ¼ of the communication wavelength. Since the parts 15a and 15b are opposed to each other with the dielectric substrate 11 in between, the polarities are opposite and the signal levels are high at these opposed positions, and function as an electric dipole. Therefore, the coupling electrode 18 can efficiently emit a longitudinal wave of the electric field in the thickness direction of the substrate, and as a result, the coupling strength between the coupling electrodes disposed at the opposing positions is high. Thus, good communication characteristics can be realized.

  The high-frequency coupler 1 having such a configuration is manufactured by the following manufacturing process. First, with respect to the double-sided copper foil substrate in which copper foil is pasted as a conductive layer on both surfaces of the dielectric substrate 11, a part of the copper foil is removed by etching treatment, and a meander-shaped wiring 12a having a plurality of folded portions, 12b is formed. Next, a hole is formed by drilling or laser processing at one end of the wiring 12a, a portion where the one end of the wiring 12b overlaps, and the other end of the wiring 12b, and the hole is plated or conductive such as a conductive paste. By filling the conductive material, the connecting through holes 14a and 14b are completed.

  Through the above steps, the wiring 12a formed on the surface 11a of the dielectric substrate 11 and the wiring 12b on the other surface 11b are electrically connected to function as the coupling electrode 18, and both ends of the coupling electrode 18 are connected. The parts 19 a and 19 b function as the connection terminal part 19.

  Thus, the high-frequency coupler 1 is excellent in that the coupling electrode 18 is connected to the ends of the wirings 12a and 12b formed on both surfaces of the dielectric substrate 11 via the connection through holes 14a. Mechanical strength and downsizing of the entire high-frequency coupler 1 can be realized. Moreover, the high frequency coupler 1 can be easily manufactured by patterning a single double-sided copper foil substrate by the above process.

  Thus, the mechanical strength is high on the dielectric substrate 11 without using the metal wire 207 that may be deformed by an external force as compared with the high frequency coupler according to the conventional example as shown in FIG. This is because the coupling electrode 18 is mounted. Moreover, the overall size of the high-frequency coupler can be reduced because the coupling strength can be increased by adjusting the length of the wiring 15 without necessarily increasing the area of the electrode.

  In the high-frequency coupler 1, as a material for the dielectric substrate 11, glass, a paper base material, or a glass fiber woven fabric is hardened with an epoxy resin, a phenol resin, or the like, for example, a glass epoxy, a glass composite substrate, Dielectric constant polyimide, liquid crystal polymer, polytetrafluoroethylene, polystyrene, polyethylene, polypropylene, or the like, or a material obtained by making them porous can be used. In particular, the dielectric substrate 11 is preferably made of a low dielectric constant material in terms of electrical characteristics.

  In the manufacturing process described above, in the high-frequency coupler 1, the wirings 12a and 12b are formed by etching using a double-sided substrate to which a copper foil is attached, but the both surfaces 11a and 11b of the dielectric substrate 11 are plated. Alternatively, it may be formed directly by a masking state by a vacuum deposition method or by performing a patterning process such as etching after the formation.

  In addition to copper, a good conductor such as aluminum, gold, or silver can be used as the material for the wirings 12a and 12b. However, the material is not limited to these materials, and any conductor having a high conductivity can be used. be able to.

  Further, since the coupling electrode 18 has the wirings 12a and 12b formed in a meander shape having a plurality of folded portions, the space of each surface 11a and 11b of the dielectric substrate 11 can be effectively utilized. The size of the coupling electrode 18 itself can be reduced.

  As will be described later, the length of the coupling electrode 18 is approximately one wavelength of the communication frequency. However, the formation space of the coupling electrode 18 can be reduced by forming these wirings so as to be closely packed. This is because the area of the high-frequency coupler 1 can be reduced.

  As described above, the wiring patterns of the wirings 12a and 12b in the coupling electrode 18 are formed by connecting a plurality of meander-shaped patterns having folded portions having different shapes from the viewpoint of effectively using the space of the dielectric substrate 11. Alternatively, an L-shaped or arc-shaped repetitive pattern may be used.

  Next, in order to investigate the performance of the high-frequency coupler 1, the coupling strength was analyzed using a three-dimensional electromagnetic field simulator HFSS manufactured by Ansoft. Here, an analysis model of the high-frequency coupler 1 was used under the following conditions. That is, polytetrafluoroethylene was set as the material of the dielectric substrate 11, and copper was set as the conductive material of the coupling electrode 18. The size of the high-frequency coupler 1 was 6.5 mm × 6.5 mm on the surface on which the wiring pattern was formed, and the substrate thickness was 1.67 mm.

  The coupling strength is evaluated by the transmission characteristic S21 of the S parameter used for evaluating the high-frequency transmission characteristics, and the input port is connected between both ends 19a and 19b of the connection terminal 19 serving as the signal input / output terminal of the high-frequency coupler. As a result, the coupling strength S21 between the ports of the pair of high frequency couplers was calculated. FIG. 3 shows a relative arrangement between the high-frequency couplers 1 and 150 used for the analysis of the coupling strength S21. Here, the coupling strength S21 is set in a state where the wiring 12a of the coupling electrode 18 of the high-frequency coupler 1 and the electrode 150a of the high-frequency coupler 150 are opposed to each other so that the central axes thereof coincide with each other and are spaced by 15 mm and 100 mm. The frequency characteristics were investigated. In this example, one high frequency coupler 150 has a plate-like electrode 150a, and a reference high frequency coupler which is a reference machine for evaluation is used.

  In addition, in order to see the generation state of the electric field in the high frequency coupler 1, the electric field vector distribution in the vicinity of the high frequency coupler 1 was also examined.

  FIG. 4 is an analysis of the electric field distribution at 4.5 GHz of the high-frequency coupler 1, and shows the electric field distribution in a cross section obtained by dividing the dotted line Y-Y ′ in FIG. 2 in the thickness direction. As is apparent from FIG. 4, a strong electric field distribution is observed between the meander-shaped wirings 12 a and 12 b on both surfaces 11 a and 11 b of the dielectric substrate 11 constituting the coupling electrode 18, and the outer side from the coupling electrode 18. An electric field is distributed on the circular arc toward.

  FIG. 5 shows the electric field distribution on a surface 1 mm away in the vertical direction from the surface 11 a on which the wiring 12 a of the high-frequency coupler 1 is formed. As apparent from FIG. 5, the electric field is distributed substantially concentrically from the central portions 15 a and 15 b of the coupling electrode 18. For this reason, a longitudinal wave of a strong electric field is radiated in the thickness direction of the high-frequency coupler 1 during resonance.

  This is because the length of the coupling electrode 18 is approximately one wavelength, and therefore, there is a potential difference between the end portion of the coupling electrode 18 and the central portion 15a of the wiring 12a corresponding to the portion of the wavelength ¼. Because it becomes the maximum. Thus, it was confirmed by analysis that the high-frequency coupler 1 generates a strong electric field around the center of the substrate surface.

  FIG. 6 shows an analysis result of the coupling strength S21 between the high-frequency coupler 1 and the reference high-frequency coupler 150, and has a coupling strength of −25 dB near 4.5 GHz at a communication distance of 15 mm facing distance. A broadband characteristic of 0.86 GHz was obtained in the -3 dB bandwidth, which is a frequency band indicating the intensity attenuated by 3 dB from the maximum intensity. For example, TransferJet (registered trademark) requires a bandwidth of 560 MHz. Generally, the center frequency shifts due to variations in high frequency couplers and impedance matching with the circuit board. Since the bandwidth is 1.5 times, good communication can be performed without being affected by these variations. In addition, a communication interruption of -60 dB or less is obtained at a non-communication distance of 100 mm facing distance.

  As described above, in the high-frequency coupler 1 according to the first embodiment, as is apparent from the above simulation, it is possible to realize good communication characteristics and further achieve coexistence with mechanical strength. The entire apparatus can be reduced in size.

<Second Embodiment>
Next, as an antenna device incorporated in the communication system 100, a high-frequency coupler 2 according to a second embodiment as shown in FIGS. 7 and 8 will be described.

  FIGS. 7 and 8 show the high-frequency coupler 2 from different viewpoints, and show the winding state of the coil 28 described later through the dielectric substrates 21, 22a, and 22b for easy understanding. .

  As shown in FIGS. 7 and 8, the high-frequency coupler 2 includes dielectric substrates 21, 22a, and 22b, and a coil 28 having a length substantially equal to the communication wavelength. A connection terminal portion 29 is formed for connection.

  The dielectric substrates 22a and 22b are dielectric members that are laminated on both surfaces of the dielectric substrate 21 by, for example, a bonding process described later. The dielectric substrates 21, 22a, and 22b are made of glass, paper base material, or glass fiber woven fabric hardened with epoxy resin, phenol resin, or the like, for example, glass epoxy, glass composite substrate, or low dielectric Rate polyimide, liquid crystal polymer, polytetrafluoroethylene, polystyrene, polyethylene, polypropylene, and the like, and materials obtained by making them porous. In particular, the dielectric substrates 21, 22a, and 22b are preferably made of a low dielectric constant material in terms of electrical characteristics.

  The connection terminal unit 29 is a terminal for connection with the above-described transmission / reception circuit unit 104, for example, connection with a flexible printed circuit board through an anisotropic conductive film, or a thin coaxial cable through a surface mount receptacle. It becomes connection means such as connection. For this reason, the shape of the connection terminal portion 29 is adjusted. Depending on the connection method, a connection through hole 25a, which will be described later, is omitted, and the terminals are arranged on both surfaces of the dielectric substrate 21, respectively. May be adopted.

  The coil 28 functions as a coupling electrode that is electromagnetically coupled to an electrode of another antenna device disposed at an opposing position so as to be communicable. The coil 28 is configured by connecting an upper surface coil 27a and a lower surface coil 27b, which will be described later, and the wiring length connecting the upper surface coil 27a and the lower surface coil 27b, that is, the length of the coil 28 is determined by the communication frequency. It is adjusted to be approximately one wavelength. Further, the coil 28 has a dielectric substrate at a position away from the connection terminal portion 29 that is an end portion of the upper surface coil 27a and the lower surface coil 27b that are not connected to the connection through-hole 25b described later. Opposing 21, 22a and 22b.

  As a specific example, in the coil 28, positions that are a quarter of the communication wavelength away from the two end portions of the connection terminal portion 29 are the center portions 26 a and 26 b of the dielectric substrates 21, 22 a, and 22 b, respectively.

  As described above, in the coil 28, as is clear from the following evaluation, a position that is a quarter of the communication wavelength away from the two ends of the connection terminal portion 29 sandwiches the dielectric substrates 21, 22 a, and 22 b. Since they are opposed to each other, at these opposed positions, the polarities are opposite to each other and the signal levels are high, so that they function as electric dipoles. Therefore, in the coil 28, the longitudinal wave of the electric field can be efficiently emitted in the thickness direction of the substrate, and as a result, the coupling strength between the other coupling electrodes arranged at the opposing positions is increased, Good communication characteristics can be realized.

  The high-frequency coupler 2 having such a configuration is manufactured by the following manufacturing process. First, a plurality of upper surface lines 23a and lower surface lines 23b made of a conductive metal such as copper or aluminum are formed on both surfaces of the dielectric substrate 22a, one end of the upper surface line 23a is one end of the lower surface line 23b, and the upper surface line 23a. The other one end of the other is adjacent to the lower surface line 23b adjacent to each other with the dielectric substrate 22a interposed therebetween.

  The plurality of upper surface lines 23a and lower surface lines 23b may be formed by plating, vapor deposition or the like on both surfaces of the dielectric substrate 22a, or etching using the dielectric substrate 22a covered with double-sided copper foil. It may be formed by processing.

  A plurality of through holes 24 are formed by drills, lasers, or the like at positions where the upper surface line 23a and the lower surface line 23b overlap the dielectric substrate 22a on which the upper surface line 23a and the lower surface line 23b are formed. By filling these through holes 24 with a metal plating process or a conductive paste, all the upper surface lines 23a and lower surface lines 23b formed on both surfaces of the dielectric substrate 22a are electrically connected via the through holes 24, and solenoids A shaped upper coil 27a is completed. Similarly to the upper surface coil 27a, the lower surface coil 27b is formed on the dielectric substrate 22b. Note that one end of the upper surface coil 27a is also connected to one of the connection terminal portions 29 through the through hole 24 in the above process.

  Next, connection through holes 25 a and 25 b are formed in the dielectric substrate 21. This is formed by embedding a metal plating process or a conductive paste or a metal rod in a portion opened by a drill or a laser. The dielectric substrate 22a is bonded to both surfaces of the dielectric substrate 21 so that one end of the upper surface coil 27a overlaps the connection through hole 25b, and one end of the lower surface coil 27b is connected to the connection through hole 25b and the lower surface coil 27b. They are bonded and electrically connected so that one end overlaps the connection through hole 25a. As a result, all the metal portions are connected, and one coil 28 having the connection terminal portions 29 at both ends is formed in the dielectric substrates 21, 22a, and 22b.

  As described above, the substrates can be bonded to each other depending on the material of the dielectric substrate, but it is preferable to use an adhesive from the viewpoint of preventing deformation and the like. If both ends of the connection through holes 25a and 25b that require electrical connection are convex with respect to the dielectric substrate 21, the adhesive penetrates the adhesive and reliably connects with the upper surface coil 27a and the lower surface coil 27b. be able to. Furthermore, in order to ensure the connection, it is preferable to omit an adhesive around the connection portion or use an anisotropic conductive film containing anisotropic conductive particles.

  Further, the following method may be used for connection between the upper surface coil 27a formed on the dielectric substrate 22a and the lower surface coil 27b formed on the dielectric substrate 22b. First, the dielectric substrate 22a on which the upper surface coil 27a is formed and the dielectric substrate 22b on which the lower surface coil 27b is formed are attached to both surfaces of the dielectric substrate 21 with an adhesive or the like. Thereafter, holes are formed on both ends of the upper surface coil 27a and the lower surface coil 27b with a drill or the like, one end of the upper surface coil 27a and the lower surface coil 27b is connected by the connection through hole 25b, and the other end of the lower surface coil 27b is connected through. The coil 28 can be formed by connecting to the connection terminal portion 29 that has been prepared in advance at the time of forming the upper surface line 23a through the hole 25a. The coil 28 functions as a coupling electrode that is electromagnetically coupled to an electrode of another antenna device disposed at an opposing position to enable communication.

  In this manner, the coil 28 is wound around the upper and lower surfaces of the dielectric substrates 22a and 22b laminated on both surfaces of the dielectric substrate 21 in a coil shape through the through holes 24, so that the dielectric substrates 22a and 22b Since one end of the wiring wound on both surfaces is connected via the connection through hole 25b, it is possible to realize good mechanical strength and downsizing of the entire high-frequency coupler 1.

  As described above, the mechanical strength is high on the dielectric substrate 21 without using the metal wire 207 that may be deformed by an external force as compared with the high frequency coupler according to the conventional example as shown in FIG. This is because the coil 28 that functions as a coupling electrode is mounted. Further, the overall size of the high-frequency coupler can be reduced because the coupling strength can be increased by adjusting the overall length of the coil 28 without necessarily increasing the area of the electrode.

  Next, in order to investigate the performance of the high-frequency coupler 2, the coupling strength was analyzed using a three-dimensional electromagnetic field simulator HFSS manufactured by Ansoft. Here, an analysis model of the high frequency coupler 2 was used under the following conditions. That is, as the dielectric material, polytetrafluoroethylene is set for the dielectric substrate 21, and liquid crystal polymer is set for the dielectric substrates 22a and 22b. The material of the coil 28 was set to copper. The size of the high-frequency coupler 2 was 6.5 mm × 6.5 mm on the surface on which the wiring pattern was formed, and the substrate thickness was 2 mm.

  The coupling strength is evaluated by the S-parameter transmission characteristic S21 used for evaluating the high-frequency transmission characteristic, and the power input port is between both ends of the connection terminal portion 29 serving as the signal input / output terminal of the high-frequency coupler. FIG. 9 shows a relative arrangement between the high-frequency couplers using the coupling strength S21 for analysis. Here, the frequency characteristic of the coupling strength S21 is examined with the upper surface coil 27a of the high-frequency coupler 2 and the electrode 250a of the high-frequency coupler 250 facing each other so that the central axes thereof are coincident with each other and spaced by 15 mm and 100 mm. It was. In this example, one high-frequency coupler 250 is a reference high-frequency coupler that has a plate-like electrode 250a and is a reference machine for evaluation.

  Further, in order to see the electric field generation state in the high frequency coupler 2, the electric field vector distribution in the vicinity of the high frequency coupler 2 was also examined.

  FIG. 10 shows an analysis portion of the electric field vector distribution, and passes through the portion indicated by the dotted line XX ′ in the drawing, that is, the central portions 26a and 26b of the high-frequency coupler 2, and the XY axis that is the width direction of the substrate. The plane extending in the Z axis, which is the thickness direction, is the analysis plane. Here, the direction from the center toward the connection terminal portion 29 with respect to the rectangular parallelepiped high-frequency coupler 2 is a Y axis that is the length direction.

  11 and 12 show the analysis results of the electric field vector distribution at 4.5 GHz, which is the resonance frequency of the high-frequency coupler 2 on the YZ plane and the XY plane, respectively. Here, FIG. 12 shows an electric field distribution on a surface 1 mm away in the vertical direction from the surface on which the upper surface coil 27a of the high frequency coupler 2 is formed. As is apparent from these two figures, electrodes having different polarities are formed on the upper coil 27a and the lower coil 27b, and a strong electric field distribution is generated therebetween. For this reason, a longitudinal wave of a strong electric field at the time of resonance is radiated in the Z-axis direction, which is the thickness direction of the high-frequency coupler 2.

  FIG. 13 shows an analysis result of the coupling strength S21 between the high-frequency coupler 2 and the reference high-frequency coupler 250, and has a coupling strength of −25 dB near 4.5 GHz at a communication distance of 15 mm facing, A wide band characteristic of 1.1 GHz or more was obtained in the −3 dB bandwidth. For example, TransferJet (registered trademark) requires a bandwidth of 560 MHz. Generally, the center frequency shifts due to variations in high frequency couplers and impedance matching with the circuit board. Since the bandwidth is doubled, good communication can be performed without being affected by these variations. In addition, a communication blocking property of −47 dB or less is obtained at a non-communication distance of an opposing distance of 100 mm.

  As described above, in the high-frequency coupler 2 according to the second embodiment, as is clear from the above simulation, it is possible to realize good communication characteristics and further achieve coexistence with mechanical strength. The entire apparatus can be reduced in size.

  1, 2, 102, 106, 150, 250 High frequency coupler, 11, 21, 22a, 22b Dielectric substrate, 11a, 11b surface, 12a, 12b Wiring, 14a, 14b, 25a, 25b Connecting through hole, 15a, 15b, 26a, 26b Center part, 18, 103, 107, 208 Coupling electrode, 19, 29 Connection terminal part, 19a, 19b End part, 23a, 27a Upper surface line, 23b, 27b Lower surface line, 24 Through hole, 28 Coil , 100 communication system, 101, 105 communication device, 104, 108 transmission / reception circuit unit, 150a, 250a electrode, 201 printed circuit board, 202 ground, 203 stub, 205 transmission / reception circuit, 207 metal wire,

Claims (4)

In an antenna device that performs information communication by electromagnetic field coupling between a pair of opposed electrodes at a predetermined communication wavelength,
One end of the wiring formed on both surfaces of the dielectric substrate is connected through a through hole, and includes a coupling electrode that is electromagnetically coupled to an electrode of another antenna device disposed at an opposing position to enable communication ,
The wiring connected through the through hole has a wiring length that is substantially the same as the communication wavelength, and is separated from the end of the wiring not connected to the through hole by a quarter of the communication wavelength. Each antenna device is opposed to each other with the dielectric substrate interposed therebetween.   2. The antenna device according to claim 1, wherein the coupling electrode is formed by connecting one end of a meander-shaped wiring having a plurality of folded portions to both surfaces of the dielectric substrate through a through hole. First and second dielectric layers are laminated on both surfaces of the dielectric substrate,
The coupling electrode is wound in a coil shape on the upper and lower surfaces of the first and second dielectric layers laminated on both surfaces of the dielectric substrate via through holes, and is wound on both surfaces of the dielectric substrate. The antenna device according to claim 2, wherein one ends of the formed wirings are connected to each other through a through hole. In a communication device that performs information communication by electromagnetic coupling between electrodes of other communication devices arranged at opposite positions with a predetermined communication wavelength,
One end of wiring formed on both surfaces of the dielectric substrate is connected through a through hole, and a coupling electrode that is electromagnetically coupled to an electrode of another antenna device disposed at an opposing position to enable communication,
A transmission / reception processing unit that is electrically connected via a connection terminal formed at an end of the wiring that is not connected to the through hole, and that performs signal transmission / reception processing;
The wiring connected through the through hole has a wiring length that is substantially the same as the communication wavelength, and each position that is a quarter of the communication wavelength away from the connection terminal is the dielectric substrate. A communication device characterized by facing each other with a gap therebetween.

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