Wireless communication system

Abstract

To provide a wireless communication system that can suppress malfunctions caused by overheating. [Solution] The wireless communication system has a first transmission line, a second transmission line, a third transmission line, and a fourth transmission line, the first and second transmission lines are arranged in series with respect to each other, the third and fourth transmission lines are arranged in parallel with respect to each other, the third and fourth transmission lines are movable relative to the first and second transmission lines, the third and fourth transmission lines communicate with the first and / or second transmission lines by electric field coupling, magnetic field coupling, or both electric field coupling and magnetic field coupling, the first and second transmission lines transmit signals in opposite directions with respect to each other, or the third and fourth transmission lines transmit signals in opposite directions with respect to each other.

Description

Technical Field

[0001] The present disclosure relates to a wireless communication system.

Background Art

[0002] In recent years, technologies for controlling devices having rotatable parts such as robot hands and network cameras through communication via a network or the like have been developing. In order to solve problems such as cables getting entangled with a shaft when rotating the rotatable part of such a device, it can be configured to enable data communication through the rotating part.

[0003] Further, Patent Document 1 discloses a system that performs bidirectional data communication between a fixed first transmission line and a second transmission line that moves relative to the first transmission line.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Here, when performing transmission in a wireless communication system, it is necessary to communicate within the band where the coupler operates as an antenna resonator. On the other hand, when attempting to perform wide - band data transmission without treating the coupler as a resonator, impedance matching cannot be achieved over the entire band with respect to the output impedance of the buffer (for example, 50Ω), and it is necessary to have a configuration with a high impedance.

[0006] As a result, impedance mismatch occurs at the connection point between the coupler and the transmit buffer, causing much of the input signal energy to be reflected, preventing proper communication. Furthermore, if the reflected signal energy returns to the transmit buffer, it can overheat and increase the likelihood of failure, which is undesirable.

[0007] This disclosure aims to provide a wireless communication system that can suppress failures caused by overheating. [Means for solving the problem]

[0008] The wireless communication system includes a first transmission line, a second transmission line, a third transmission line, and a fourth transmission line, wherein the first and second transmission lines are arranged in series with respect to each other, the third and fourth transmission lines are arranged in parallel with respect to each other, the third and fourth transmission lines are movable relative to the first and second transmission lines, the third and fourth transmission lines communicate with the first and / or second transmission lines by electric field coupling, magnetic field coupling, or both electric field coupling and magnetic field coupling, the first and second transmission lines transmit signals in opposite directions with respect to each other, or the third and fourth transmission lines transmit signals in opposite directions with respect to each other. [Effects of the Invention]

[0009] According to this disclosure, it is possible to realize a wireless communication system that can suppress failures caused by overheating. [Brief explanation of the drawing]

[0010] [Figure 1] This figure shows an example configuration of a wireless communication system according to the first embodiment of this disclosure. [Figure 2] This is a diagram illustrating the operating principle of a wireless communication system. [Figure 3] This figure shows the results of a simulation of the operation of a wireless communication system according to the first embodiment of this disclosure. [Figure 4]This figure shows the results of a simulation of the operation of a wireless communication system according to the first embodiment of this disclosure. [Figure 5] This figure shows an example configuration of a wireless communication system according to the first embodiment of this disclosure. [Figure 6] This figure shows an example configuration of a wireless communication system according to the second embodiment of this disclosure. [Figure 7] This figure shows the results of a simulation of the operation of a wireless communication system according to the second embodiment of this disclosure. [Figure 8] This figure shows the results of a simulation of the operation of a wireless communication system according to the second embodiment of this disclosure. [Figure 9] This figure shows an example configuration of a wireless communication system according to the third embodiment of this disclosure. [Modes for carrying out the invention]

[0011] Hereinafter, preferred embodiments to which the present invention can be applied will be described in detail with reference to the drawings. In the following description, components common to multiple drawings are denoted by the same reference numerals. Therefore, the common components will be described by referring to multiple drawings together, and the description of components denoted by the same reference numerals will be omitted as appropriate.

[0012] Figure 2 is a diagram illustrating the operating principle of the wireless communication system 20, and is a schematic representation of the part where signals are transmitted from a short coupler to a bidirectional transmission path.

[0013] As shown in Figure 2, the wireless communication system 20 includes couplers 101, 102, 211, terminators 103, 104, 107, 108, comparator 105, combiner 106, signal source 115, and transmit buffer 116. Terminators 103 and 107 provide matched termination to the respective ends of coupler 101. Terminators 104 and 108 provide matched termination to the respective ends of coupler 102. Couplers 101 and 102 are positioned close together, with one end connected to terminators 107 and 108 facing each other.

[0014] The combiner 106 is connected to the approximate centers of the combiners 101 and 102 with electrically approximately equal lengths. The signal source 115 is connected to the transmission buffer 116. The transmission buffer 116 is connected to the approximate center of the combiner 211.

[0015] Note that, in order to perform bidirectional communication, the configuration when using the combiners 101 and 102 as signal transmission combiners and the combiner 211 as a signal reception combiner is omitted.

[0016] In the wireless communication system 20, impedance mismatch occurs at the connection between the combiner 211 and the transmission buffer 116, and most of the input signal energy is reflected, making it impossible to perform proper communication. Furthermore, when the reflected signal energy returns to the transmission buffer, the transmission buffer 116 generates heat and the possibility of failure increases, which is not preferable. Therefore, the configuration of a wireless communication system with less reflection is shown below.

[0017] (First Embodiment) First, the first embodiment of the present disclosure will be described.

[0018] FIG. 1 is a diagram showing a configuration example of a wireless communication system 10 according to the first embodiment of the present disclosure. As shown in FIG. 1, the wireless communication system 10 includes combiners 101, 102, 111, 112, terminators 103, 104, 113, 114, a comparator 105, a synthesizer 106, a signal source 115, and transmission buffers 116, 117.

[0019] The combiners 101 and 102 are each composed of the same transmission line. The combiners 111 and 112 are each composed of the same transmission line. The combiners 101 and 102 are electromagnetically coupled to the combiners 111 and 112 to perform wireless communication.

[0020] The terminators 103 and 104 are respectively connected to one ends of the combiners 101 and 102 to impedance-match the combiners 101 and 102. The terminators 113 and 114 are respectively connected to one ends of the combiners 111 and 112 to impedance-match the combiners 111 and 112.

[0021] The combiner 106 is connected to the opposite end of the couplers 101 and 102, from the end to which the terminators 103 and 104 are connected. The combiner 106 combines the signals received by the couplers 101 and 102 and outputs the result. The couplers 101 and 102 and the combiner 106 are electrically connected by approximately equal lengths.

[0022] The comparator 105 is connected to the combiner 106 and detects the rising and falling edges of the signal output from the combiner 106.

[0023] The signal source 115 is connected to the transmit buffers 116 and 117, and the same signal is input to the transmit buffers 116 and 117 at the same time. A signal distribution device, such as a resistor divider, may also be connected between the signal source 115 and the transmit buffers 116 and 117.

[0024] Transmit buffers 116 and 117 are connected to the opposite end of couplers 111 and 112 from the end to which terminators 113 and 114 are connected. Transmit buffers 116 and 117 input signals from signal source 115 to couplers 111 and 112 at the same time. Couplers 111 and 112 and transmit buffers 116 and 117 are electrically connected by approximately equal lengths.

[0025] Couplers 101 and 102 are positioned close together with one end facing the other that connects to the combiner 106. Alternatively, couplers 101 and 102 may be positioned close together with one end facing the other that connects to the terminals 103 and 104, or both ends that connect to the combiner 106 and the ends that connect to the terminals 103 and 104 may be positioned close together.

[0026] Couplers 111 and 112 have means to move relative to coupler 101 or 102 while maintaining a distance from it, and perform wireless communication while moving. Couplers 111 and 112 are arranged to move parallel to each other along the direction of movement while maintaining approximately equal levels of electromagnetic field coupling with coupler 101 or 102.

[0027] For example, couplers 101 and 102 are formed on a first substrate. Couplers 111 and 112 are formed on a second substrate. Couplers 111 and 112 are movable in the horizontal direction of Figure 1 while facing couplers 101 and / or 102.

[0028] Next, the operation of the wireless communication system 10 according to the first embodiment will be described.

[0029] The signal input from signal source 115 is input to couplers 111 and 112 via transmit buffers 116 and 117. The signals input to couplers 111 and 112 are transmitted to couplers 101 and 102 by electromagnetic field coupling.

[0030] At this time, couplers 111 and 112 receive signals in opposite directions, so the signal transmitted to couplers 101 and 102 is a combined signal of two signals with opposite characteristics. Therefore, the combiner 106 always receives signals with opposite characteristics from couplers 101 and 102. The signal output from this combiner 106 has the characteristic that even if couplers 111 and 112 move, the intensity will always be approximately equal within a certain frequency range.

[0031] As a result, even if the couplers 111 and 112 move along the coupler 101 or 102, spanning adjacent parts of the couplers 101 and 102, there is always a signal transmitted to the comparator 105 with approximately constant strength, enabling data communication even while moving.

[0032] Since terminators 113 and 114 mutually terminate couplers 111 and 112, respectively, the energy of the signals input to couplers 111 and 112 from transmit buffers 116 and 117 is almost entirely absorbed and consumed by terminators 113 and 114. As a result, only a small amount of energy is reflected back from couplers 111 and 112 to transmit buffers 116 and 117, preventing heat generation and failure due to reflection in transmit buffers 116 and 117.

[0033] Figure 3 shows the characteristics obtained when an electromagnetic field simulation is performed on the wireless communication system 10 according to the first embodiment, and the energy transferred from couplers 111 and 112 to couplers 101 and 102 is obtained as the output of the combiner 106. Figure 3 shows the change in characteristics when couplers 111 and 112 move along couplers 101 and 102 from the coupler 101 side to the coupler 102 side.

[0034] As shown in Figure 3, the output characteristics of the combiner 106 show little change due to movement below 5 GHz, and large change above 5 GHz. Here, when the combiner 106 is in a position that almost overlaps with either the couplers 111, 112 or the other couplers 101, 102, the characteristics have a peak around 4.2 GHz. As the couplers 111, 112 approach the ends of the couplers 101, 102 that connect to the combiner 106, the characteristics become continuously larger as the frequency increases. The frequency at which the first peak occurs in the characteristics obtained as the output of the combiner 106 is determined by the length of the couplers 111, 112 in the direction of movement. Figure 3 shows that stable communication is possible even while moving at frequencies around 5 GHz and below.

[0035] Figure 4 shows the results of an electromagnetic field simulation of the wireless communication system 10 according to the first embodiment, showing the waveform input from the signal source 115 and the waveforms output from the comparators 105 at the positions of the couplers 111 and 112. As shown in Figure 4, the waveform input from the signal source 115 can always be correctly reproduced as the output of the comparator 105.

[0036] From the above results, it was found that by using the wireless communication system 10 of this embodiment, data can be transmitted from a moving coupler to a coupler positioned in close proximity in the direction of movement.

[0037] Figure 4 shows the simulation results for 15 Gbps data transmission. As shown in Figure 3, the characteristics obtained as the output of the combiner 106 reach their first peak around 4.3 GHz and their minimum value around 8.6 GHz. 8.6 GHz is the frequency band of the fundamental wave at 17.2 Gbps, but the transmittable frequency band decreases depending on the frequency characteristics of the couplers 111 and 112, and in the coupler of this embodiment, the limit is 15 Gbps, which has a frequency band with a peak frequency reduced by about 8 dB. In other words, the wireless communication system 10 is preferably used at a frequency or lower that is about 8 dB lower than the first peak of the narrowest frequency characteristics obtained as the output of the combiner 106, which is determined by the length of the couplers 111 and 112 in the direction of movement.

[0038] The example shown uses the wireless communication system 10, with the mobile couplers 111 and 112 used as transmitting couplers and couplers 101 and 102 used as receiving couplers. Data transmission is possible even if the transmitting and receiving couplers are swapped.

[0039] As described above, the wireless communication system 10 has couplers 101, 102, 111, and 112. Couplers 101, 102, 111, and 112 are examples of transmission lines. Couplers 101 and 102 are arranged in series with respect to each other. Couplers 111 and 112 are arranged in parallel with respect to each other.

[0040] Couplers 111 and 112 are movable relative to couplers 101 and 102. Couplers 111 and 112 communicate with coupler 101 and / or coupler 102 by electric field coupling, magnetic field coupling, or both electric field coupling and magnetic field coupling.

[0041] The couplers 111 and 112 are approximately the same size as each other. The longitudinal lengths of couplers 111 and 112 are shorter than the longitudinal lengths of couplers 101 and 102. Couplers 101 and 102 are formed on a first substrate. Couplers 111 and 112 are formed on a second substrate.

[0042] The transmitting circuit has a signal source 115 and transmit buffers 116 and 117, which supply signals to couplers 111 and 112. Couplers 111 and 112 transmit signals in opposite directions to each other. The receiving circuit has a comparator 105 and a combiner 106, which receive signals from coupler 101 and coupler 102.

[0043] Coupler 101 has a left end and a right end. Coupler 102 has a left end and a right end. Coupler 111 has a left end and a right end. Coupler 112 has a left end and a right end.

[0044] The transmit buffer 117 supplies a signal to the right end of the coupler 111, and the transmit buffer 116 supplies a signal to the left end of the coupler 112.

[0045] The combiner 106 receives the signal from the right end of the coupler 101 and the signal from the left end of the coupler 102. The right end of coupler 101 is connected to the terminator 103. The right end of coupler 102 is connected to the terminator 104. The right end of coupler 111 is connected to the terminator 113. The right end of coupler 112 is connected to the terminator 114.

[0046] The signal source 115 outputs a signal. The transmit buffer 117 receives the output signal from the signal source 115 and supplies the signal to the right end of the coupler 111. The transmit buffer 116 receives the output signal from the signal source 115 and supplies the signal to the left end of the coupler 112. Transmit buffers 117 and 116 supply equivalent signals to the right end of the coupler 111 and the left end of the coupler 112.

[0047] The combiner 106 combines the signal at the right end of the coupler 101 with the signal at the left end of the coupler 102. The comparator 105 detects the rising and falling edges of the signal combined by the combiner 106.

[0048] The right end of coupler 101 and the left end of coupler 102 face each other. Alternatively, the left end of coupler 101 and the right end of coupler 102 may also face each other. For example, couplers 101 and 102 are arranged in series on a straight line relative to each other.

[0049] Alternatively, the lengths of couplers 101 and 102 may be approximately equal, with the right end of coupler 101 and the left end of coupler 102 facing each other, and the left end of coupler 101 and the right end of coupler 102 facing each other. For example, couplers 101 and 102 may be arranged in series in a circular shape.

[0050] As shown in Figure 3, communication takes place at or below the higher of two frequencies that drop 8 dB from the peak of the narrowest frequency response among the frequency characteristics of the output signal of the combiner 106, which changes depending on the movement positions of the couplers 111 and 112.

[0051] Figure 5 shows an example configuration of a wireless communication system 50 obtained by replacing the coupler for transmitting and receiving signals with that of the wireless communication system 10 shown in Figure 1. Components in Figure 5 that have the same function as those in Figure 1 are denoted by the same reference numerals, and their detailed explanations are omitted.

[0052] As shown in Figure 5, the wireless communication system 50 includes couplers 101, 102, 111, 112, terminators 103, 104, 113, 114, comparator 105, combiner 106, signal source 115, and transmit buffers 116, 117.

[0053] The combiner 106 is connected to the opposite end of the couplers 111 and 112, from the end to which the terminators 113 and 114 are connected. The combiner 106 combines the signals received by the couplers 111 and 112 and outputs them. The couplers 111 and 112 and the combiner 106 are electrically connected by approximately equal lengths.

[0054] Transmit buffers 116 and 117 are connected to the opposite end of couplers 101 and 102 from the end to which terminators 103 and 104 are connected. Transmit buffers 116 and 117 input signals from signal source 115 to couplers 101 and 102 at the same time. Couplers 101 and 102 and transmit buffers 116 and 117 are electrically connected by approximately equal lengths.

[0055] The characteristics obtained as the output of the combiner 106 in the wireless communication system 50 are substantially the same as the characteristics obtained as the output of the combiner 106 in the wireless communication system 10. Therefore, similar to the wireless communication system 10, data transmission is possible even if the couplers 111 and 112 move along couplers 101 and 102 from the coupler 101 side to the coupler 102 side.

[0056] As described above, the transmit buffer 116 supplies a signal to the right end of the coupler 101, and the transmit buffer 117 supplies a signal to the left end of the coupler 102. Couplers 101 and 102 transmit signals in opposite directions to each other. The combiner 106 receives the signal from the right end of coupler 111 and the signal from the left end of coupler 112.

[0057] The left end of coupler 101 is connected to terminator 103. The right end of coupler 102 is connected to terminator 104. The left end of coupler 111 is connected to terminator 113. The right end of coupler 112 is connected to terminator 114.

[0058] According to the first embodiment of this disclosure, a wireless communication system is realized that enables bidirectional data transmission between a moving coupler and a coupler positioned in close proximity in the direction of movement, and which has a low probability of transmission buffer overheating and failure.

[0059] (Second embodiment) Next, a second embodiment of the present disclosure will be described. In the first embodiment, a case was described in which the moving coupler consists of two substantially equal transmission paths that run parallel to the direction of movement and transmit signals in opposite directions. In the second embodiment, another example of a moving coupler will be shown.

[0060] Figure 6 shows an example configuration of the wireless communication system 60 in a second embodiment of this disclosure. Components in Figure 6 that have the same functions as those in Figure 1 are denoted by the same reference numerals, and their detailed descriptions are omitted.

[0061] As shown in Figure 6, the wireless communication system 60 includes couplers 101, 102, 111, 112, terminators 103, 104, 114, comparator 105, combiner 106, signal source 115, transmit buffer 116, and connection section 618.

[0062] The connection section 618 connects one end of the coupler 111 of the wireless communication system 10 in the first embodiment to the terminator 113, and the other end to the coupler 112 to the transmit buffer, in some way. Preferably, the connection section 618 connects the couplers 111 and 112 by means of minimizing loss and reflection and delay.

[0063] Next, the operation of the wireless communication system 60 according to the second embodiment will be described.

[0064] The signal input from the transmit buffer 116 to the coupler 111 is continuously transmitted to the coupler 111, the connector 618, and the coupler 112. As a result, couplers 111 and 112 transmit the same signal in opposite directions to each other.

[0065] Since the terminator 114 provides matched termination to the coupler 112, the signal input to the coupler 111 from the transmit buffer 116 is transmitted to the junction 618 and the coupler 112, and then absorbed or consumed by the terminator 114. Therefore, no energy is reflected from the coupler back to the transmit buffer 116. As a result, the transmit buffer 116 does not overheat or fail due to reflection.

[0066] Figure 7 shows the characteristics obtained when an electromagnetic field simulation is performed on the wireless communication system 60 according to the second embodiment, and the energy transferred from couplers 111 and 112 to couplers 101 and 102 is obtained as the output of the combiner 106. Figure 7 shows the change in characteristics when couplers 111 and 112 move along couplers 101 and 102 from the coupler 101 side to the coupler 102 side.

[0067] Here, the direction of the signals input to the couplers 111 and 112 is the same as in the first embodiment, when signals are input to the couplers 111 and 112 from the transmit buffers 116 and 117. However, the signal input to coupler 112 is delayed by the amount transmitted between coupler 111 and the connector 618 compared to the first embodiment. Therefore, unlike the wireless communication systems 10 and 50 in the first embodiment, the wireless communication system 60 has a wide communication bandwidth when couplers 111 and 112 are positioned facing one of couplers 101 and 102, and a narrow communication bandwidth when couplers 111 and 112 are positioned facing both couplers 101 and 102.

[0068] As shown in Figure 7, the output characteristics of the combiner 106 show little change due to movement below 5 GHz, and large change above 5 GHz. As shown in Figure 7, when the combiner 106 is in a position that almost overlaps with either the couplers 111, 112 or the couplers 101, 102, the characteristics increase continuously as the frequency increases. As the couplers 111, 112 approach the ends of the couplers 101, 102 that connect to the combiner 106, the characteristics have a peak around 5 GHz. The frequency at which the first peak occurs in the characteristics obtained as the output of the combiner 106 is determined by the length of movement of the couplers 111, 112.

[0069] Here, when couplers 111 and 112 face only coupler 101, the longer the distance from the ends of couplers 101 and 102, the more the propagation characteristics become wavy at lower frequencies and above. This is a characteristic not seen in the first embodiment. Due to this characteristic, the bandwidth is narrowest when the centers of couplers 111 and 112 are in the center of couplers 101 and 102, but only signals with a data rate of 13 Gbps or less can be transmitted, having a frequency bandwidth of 6.5 GHz at a frequency 1 dB lower than the peak frequency at this time.

[0070] Figure 8 shows the waveform input from the signal source 115 and the waveform output from the comparator 105, obtained by performing an electromagnetic field simulation for the wireless communication system 60 according to the second embodiment. Here, a 13 Gbps signal is input from the signal source 115. Figure 8 shows the change in characteristics when couplers 111 and 112 move along couplers 101 and 102 from the coupler 101 side to the coupler 102 side. As shown in Figure 8, the waveform input from the signal source 115 can always be correctly reproduced as the output of the comparator 105.

[0071] From the results above, it can be seen that the wireless communication system 60, like the wireless communication system 10, is capable of transmitting data from a moving coupler to a coupler positioned close in the direction of movement. Furthermore, when the transmitting coupler and receiving coupler of the wireless communication system 60 are swapped, it operates in the same manner as the wireless communication system 50. Therefore, it is also capable of transmitting data from a fixed coupler positioned close in the direction of movement to a moving coupler.

[0072] As described above, the wireless communication system 60 has a connection section 618. The connection section 618 connects the left end of coupler 111 and the left end of coupler 112. The transmit buffer 116 supplies a signal to the right end of coupler 111. The combiner 106 receives the signal from the right end of coupler 101 and the signal from the left end of coupler 102.

[0073] The left end of coupler 101 is connected to terminator 103. The right end of coupler 102 is connected to terminator 104. The right end of coupler 112 is connected to terminator 114.

[0074] The combiner 106 combines the signal from the right end of the coupler 101 with the signal from the left end of the coupler 102.

[0075] As shown in Figure 7, communication takes place at or below the higher of two frequencies that drop by 1 dB from the peak of the narrowest frequency response among the frequency characteristics of the output signal of the combiner 106, which changes depending on the movement positions of the couplers 111 and 112.

[0076] As described above, according to the second embodiment of this disclosure, a communication system is realized that enables bidirectional data transmission between a moving coupler and a coupler positioned in close proximity in the direction of movement, without the possibility of heat generation or failure of the transmission buffer due to reflection.

[0077] (Third embodiment) Next, a third embodiment of the present disclosure will be described. In the first embodiment, the case in which the coupler is configured as a single-ended transmission line was described. In the third embodiment, the case in which the coupler is configured as a differential transmission line will be described.

[0078] Figure 9 shows an example configuration of a wireless communication system 90 in a third embodiment of this disclosure. Components in Figure 9 that have the same functions as those in Figure 1 are denoted by the same reference numerals, and their detailed descriptions are omitted.

[0079] As shown in Figure 9, the wireless communication system 90 includes couplers 901, 901', 902, 902', 911, 911', 912, 912', differential terminators 903, 904, 913, 914, comparator 905, combiner 106, 106', signal source 115, differential transmit buffer 916, and 917.

[0080] Couplers 901 and 901' are composed of transmission lines forming a differential line. Couplers 902 and 902' are composed of transmission lines forming a differential line similar to couplers 901 and 901'. Couplers 911 and 911' are composed of transmission lines forming a differential line. Couplers 912 and 912' are composed of transmission lines forming a differential line similar to couplers 911 and 911'. Couplers 901, 901', 902, and 902' are electromagnetically coupled with couplers 911, 911', 912, and 912' to perform wireless communication.

[0081] The differential terminators 903, 904, 913, and 914 are connected to one end of the couplers 901, 901', 902, 902', 911, 911', 912, and 912', respectively, to match-terminate the couplers. Note that in Figure 9, the differential terminators are represented by single resistors, but this is not the only representation.

[0082] The combiner 106 is connected to the opposite end of the couplers 901 and 902 to which the differential terminators 903 and 904 are connected. The combiner 106 combines the signals received by the couplers 901 and 902 and outputs them. The combiner 106' is connected to the opposite end of the couplers 901' and 902' to which the differential terminators 903 and 904 are connected. The combiner 106' combines the signals received by the couplers 901' and 902' and outputs them. The couplers 901 and 902 are connected to the combiner 106, and the couplers 901' and 902' are connected to the combiner 106', each with approximately equal electrical lengths.

[0083] Comparator 905 is connected to combiners 106 and 106' and detects the rising and falling edges of the differential signals output from combiners 106 and 106'.

[0084] The signal source 115 is connected to differential transmit buffers 916 and 917, and the same signal is input to differential transmit buffers 916 and 917 at the same time. A signal distribution device, such as a resistor divider, may also be connected between the signal source 115 and the differential transmit buffers 916 and 917.

[0085] The differential transmit buffer 916 is connected to the other end of the couplers 911 and 911', which is not connected to the differential terminator 913. The differential transmit buffer 917 is connected to the other end of the couplers 912 and 912', which is not connected to the differential terminator 914.

[0086] The differential transmit buffers 916 and 917 input differential signals to the couplers 911, 911', 912, and 912' at the same time. The couplers 911, 911', 912, and 912' and the differential transmit buffers 916 and 917 are electrically connected by approximately equal lengths.

[0087] Couplers 901, 901' and couplers 902, 902' are positioned close together with one end facing the other that connects to combiners 106, 106'. Alternatively, couplers 901, 901' and couplers 902, 902' may be positioned close together with one end facing the other that connects to differential terminators 903, 904, or both the ends connected to combiners 106, 106' and the ends connected to differential terminators 903, 904 may be positioned close together.

[0088] Couplers 911, 911', 912, and 912' have means to move relative to couplers 901, 901', or 902, 902' while maintaining a distance from them, and perform wireless communication while moving. Couplers 911 and 912 are arranged to move parallel to each other along the direction of movement while maintaining approximately equal electromagnetic field coupling with coupler 901 or 902. Couplers 911' and 912' are arranged to move parallel to each other along the direction of movement while maintaining approximately equal electromagnetic field coupling with coupler 901' or 902'.

[0089] Next, the operation of the wireless communication system 90 according to the third embodiment will be described.

[0090] The operation in which the signal input from the signal source 115 is transmitted from couplers 911, 911', 912, 912' to couplers 901, 901', 902, 902' is the same as the operation in the wireless communication system 10 shown in the first embodiment in which the signal is transmitted from couplers 111, 112 to couplers 101, 102. Therefore, the characteristics of the signals output from combiners 106, 106' are also the same, and even if couplers 911, 911', 912, 912' move, the system has a frequency characteristic that allows communication according to the length of couplers 911, 911', 912, 912'.

[0091] As a result, even if the couplers 911, 911', 912, and 912' move along the couplers 901, 901', or the couplers 902, 902', across adjacent couplers, there is always a signal to be transmitted to the comparator 905 at a predetermined strength or higher, enabling data communication even while moving.

[0092] Since the differential terminators 913 and 914 provide matched termination to the couplers 911, 911', 912, and 912', the signals input from the differential transmit buffers 916 and 917 are transmitted by the couplers 911, 911', 912, and 912', and then absorbed or consumed by the differential terminators 913 and 914. Therefore, no energy is reflected from the couplers back to the differential transmit buffers 916 and 917. Consequently, heat generation and failure of the differential transmit buffers 916 and 917 due to reflection do not occur.

[0093] Here, the couplers 911, 911' and couplers 912, 912' may be connected by means that minimize loss and reflection and delay, as in the second embodiment.

[0094] As described above, the wireless communication system 90, like the wireless communication system 10, can transmit data from a moving coupler to a coupler positioned close in the direction of movement. Furthermore, the wireless communication system 90 operates similarly to the wireless communication system 90 when the transmitting coupler and receiving coupler are swapped. Therefore, it can also transmit data from a fixed coupler positioned close in the direction of movement to a moving coupler.

[0095] In the first and second embodiments, the couplers 101, 102, 111, and 112 are each single-ended transmission lines.

[0096] In the third embodiment, the couplers 901, 901', 902, 902', 911, 911', 912, and 912' are each differential transmission lines.

[0097] As described above, according to the third embodiment of this disclosure, a communication system is realized in which data can be transmitted bidirectionally using differential signals between a moving coupler and a coupler positioned in close proximity in the direction of movement, and in which the transmission buffer is less likely to overheat or fail.

[0098] Furthermore, the embodiments described above are merely examples illustrating how to implement this disclosure, and they should not be interpreted as limiting the technical scope of this disclosure. In other words, this disclosure can be implemented in various ways without departing from its technical concept or its main features.

[0099] This embodiment includes the following configuration. (Item 1) The first transmission line and The second transmission line, The third transmission line, It has a fourth transmission line, The first transmission line and the second transmission line are arranged in series with respect to each other. The third transmission line and the fourth transmission line are arranged in parallel with each other. The third transmission path and the fourth transmission path are movable relative to the first transmission path and the second transmission path. The third transmission line and the fourth transmission line communicate with the first transmission line and / or the second transmission line by electric field coupling, magnetic field coupling, or both electric field coupling and magnetic field coupling. A wireless communication system characterized in that the first transmission line and the second transmission line transmit signals in opposite directions to each other, or the third transmission line and the fourth transmission line transmit signals in opposite directions to each other. (Item 2) The wireless communication system according to item 1, characterized in that the third transmission line and the fourth transmission line are substantially the same size. (Item 3) The wireless communication system according to item 2, characterized in that the longitudinal lengths of the third transmission line and the fourth transmission line are shorter than the longitudinal lengths of the first transmission line and the second transmission line. (Item 4) The first transmission line and the second transmission line are formed on the first substrate. The wireless communication system according to any one of items 1 to 3, characterized in that the third transmission line and the fourth transmission line are formed on the second substrate. (Item 5) The third transmission path and the fourth transmission path transmit signals in opposite directions to each other. A transmitting circuit that supplies signals to the third transmission line and the fourth transmission line, The wireless communication system according to any one of items 1 to 4, further comprising a receiving circuit that inputs the signal of the first transmission line and the signal of the second transmission line. (Item 6) The first transmission line has a first end and a second end, The second transmission line has a third end and a fourth end, The third transmission line has a fifth end and a sixth end, The fourth transmission line has a seventh end and an eighth end, The transmitting circuit supplies signals to the sixth end and the seventh end, The receiving circuit receives the signal from the second end and the signal from the third end, The first end is connected to the first terminator, The fourth end is connected to the second terminator. The fifth end is connected to the third terminator. The wireless communication system according to item 5, characterized in that the eighth end is connected to a fourth terminator. (Item 7) The wireless communication system according to item 6, characterized in that the transmitting circuit supplies equivalent signals to the sixth end and the seventh end. (Item 8) The wireless communication system according to item 6 or 7, characterized in that the receiving circuit has a combiner that combines the signal from the second end and the signal from the third end. (Item 9) The wireless communication system according to item 8, characterized in that the receiving circuit further includes a comparator for detecting the rising edge and falling edge of the signal synthesized by the combiner. (Item 10) The aforementioned transmitting circuit is A signal source that outputs a signal, A first transmit buffer that receives the output signal of the signal source and supplies the signal to the sixth end, A wireless communication system according to any one of items 6 to 9, characterized by having a second transmit buffer that receives the output signal of the signal source and supplies the signal to the seventh end. (Item 11) The wireless communication system according to any one of items 6 to 10, characterized in that the second end and the third end are facing each other. (Item 12) The wireless communication system according to any one of items 6 to 10, characterized in that the first end and the fourth end are facing each other. (Item 13) The second end and the third end face each other, The wireless communication system according to any one of items 6 to 10, characterized in that the first end and the fourth end are facing each other. (Item 14) The wireless communication system according to item 11 or 12, characterized in that the first transmission line and the second transmission line are arranged in series on a straight line with respect to each other. (Item 15) The wireless communication system according to item 13, characterized in that the first transmission line and the second transmission line are arranged in series in a circular shape with respect to each other. (Item 16) The wireless communication system according to item 8 or 9, characterized in that the communication is performed at a frequency below the higher of two frequencies that drop by 8 dB from the peak of the narrowest frequency characteristic among the frequency characteristics of the output signal of the combiner, which changes depending on the moving positions of the third transmission path and the fourth transmission path. (Item 17) The first transmission path and the second transmission path transmit signals in opposite directions to each other. A transmitting circuit that supplies signals to the first transmission line and the second transmission line, The wireless communication system according to any one of items 1 to 4, further comprising a receiving circuit that inputs the signal of the third transmission line and the signal of the fourth transmission line. (Item 18) The first transmission line has a first end and a second end, The second transmission line has a third end and a fourth end, The third transmission line has a fifth end and a sixth end, The fourth transmission line has a seventh end and an eighth end, The transmitting circuit supplies signals to the second end and the third end, The receiving circuit receives the signal from the sixth end and the signal from the seventh end, The first end is connected to the first terminator, The fourth end is connected to the second terminator. The fifth end is connected to the third terminator. The wireless communication system according to item 17, characterized in that the eighth end is connected to a fourth terminator. (Item 19) The first transmission line has a first end and a second end, The second transmission line has a third end and a fourth end, The third transmission line has a fifth end and a sixth end, The fourth transmission line has a seventh end and an eighth end, The wireless communication system further includes a connecting portion that connects the fifth end and the seventh end, The transmitting circuit supplies a signal to the sixth end, The receiving circuit receives the signal from the second end and the signal from the third end, The first end is connected to the first terminator, The fourth end is connected to the second terminator. The wireless communication system according to item 5, characterized in that the eighth end is connected to a fourth terminator. (Item 20) The wireless communication system according to item 19, characterized in that the receiving circuit has a combiner that combines the signal from the second end and the signal from the third end. (Item 21) The wireless communication system according to item 20, characterized in that the communication is performed at a frequency below the higher of two frequencies that drop by 1 dB from the peak of the narrowest frequency characteristic among the frequency characteristics of the output signal of the combiner, which changes depending on the moving positions of the third transmission line and the fourth transmission line. (Item 22) The wireless communication system according to any one of items 1 to 21, characterized in that the first transmission line, the second transmission line, the third transmission line, and the fourth transmission line are each single-ended transmission lines. (Item 23) The wireless communication system according to any one of items 1 to 21, characterized in that the first transmission line, the second transmission line, the third transmission line, and the fourth transmission line are each differential transmission lines. [Explanation of symbols]

[0100] 10, 20, 50, 60, 90 Wireless Communication Systems 101, 102, 111, 112, 211, 901, 901', 902, 902', 911, 911', 912, 912' Combiner 103, 104, 107, 109, 113, 114 Terminator 903, 904, 913, 914 differential terminator 105 Comparator 106, 106' synthesizer 115 Signal source 116, 117 Transmit buffer 916, 917 Differential transmit buffer

Claims

1. The first transmission line and The second transmission line, The third transmission line, It has a fourth transmission line, The first transmission line and the second transmission line are arranged in series with respect to each other. The third transmission line and the fourth transmission line are arranged in parallel with each other. The third transmission line and the fourth transmission line are movable relative to the first transmission line and the second transmission line. The third transmission line and the fourth transmission line communicate with the first transmission line and / or the second transmission line by electric field coupling, magnetic field coupling, or both electric field coupling and magnetic field coupling. A wireless communication system characterized in that the first transmission line and the second transmission line transmit signals in opposite directions to each other, or the third transmission line and the fourth transmission line transmit signals in opposite directions to each other.

2. The wireless communication system according to claim 1, characterized in that the third transmission line and the fourth transmission line are substantially the same size as each other.

3. The wireless communication system according to claim 2, characterized in that the longitudinal lengths of the third transmission line and the fourth transmission line are shorter than the longitudinal lengths of the first transmission line and the second transmission line.

4. The first transmission line and the second transmission line are formed on the first substrate. The wireless communication system according to claim 1, characterized in that the third transmission line and the fourth transmission line are formed on the second substrate.

5. The third transmission path and the fourth transmission path transmit signals in opposite directions to each other. A transmitting circuit that supplies signals to the third transmission line and the fourth transmission line, The wireless communication system according to claim 1, further comprising a receiving circuit that inputs the signal of the first transmission line and the signal of the second transmission line.

6. The first transmission line has a first end and a second end, The second transmission line has a third end and a fourth end, The third transmission line has a fifth end and a sixth end, The fourth transmission line has a seventh end and an eighth end, The transmitting circuit supplies signals to the sixth end and the seventh end, The receiving circuit receives the signal from the second end and the signal from the third end, The first end is connected to the first terminator. The fourth end is connected to the second terminator. The fifth end is connected to the third terminator. The wireless communication system according to claim 5, characterized in that the eighth end is connected to a fourth terminator.

7. The wireless communication system according to claim 6, characterized in that the transmitting circuit supplies equivalent signals to the sixth end and the seventh end.

8. The wireless communication system according to claim 6, characterized in that the receiving circuit has a combiner that combines the signal from the second end and the signal from the third end.

9. The wireless communication system according to claim 8, wherein the receiving circuit further comprises a comparator for detecting the rising edge and falling edge of the signal synthesized by the combiner.

10. The aforementioned transmitting circuit is A signal source that outputs a signal, A first transmit buffer that receives the output signal of the signal source and supplies the signal to the sixth end, The wireless communication system according to claim 6, further comprising a second transmit buffer that receives the output signal of the signal source and supplies the signal to the seventh end.

11. The wireless communication system according to claim 6, characterized in that the second end and the third end are facing each other.

12. The wireless communication system according to claim 6, characterized in that the first end and the fourth end are facing each other.

13. The second end and the third end face each other, The wireless communication system according to claim 6, characterized in that the first end and the fourth end are facing each other.

14. The wireless communication system according to claim 11, characterized in that the first transmission line and the second transmission line are arranged in series on a straight line with respect to each other.

15. The wireless communication system according to claim 13, characterized in that the first transmission line and the second transmission line are arranged in series in a circular shape relative to each other.

16. The wireless communication system according to claim 8, characterized in that the communication is performed at a frequency below the higher of two frequencies that drop by 8 dB from the peak of the narrowest frequency characteristic among the frequency characteristics of the output signal of the combiner, which changes depending on the moving positions of the third transmission line and the fourth transmission line.

17. The first transmission path and the second transmission path transmit signals in opposite directions to each other. A transmitting circuit that supplies signals to the first transmission line and the second transmission line, The wireless communication system according to claim 1, further comprising a receiving circuit that inputs the signal of the third transmission line and the signal of the fourth transmission line.

18. The first transmission line has a first end and a second end, The second transmission line has a third end and a fourth end, The third transmission line has a fifth end and a sixth end, The fourth transmission line has a seventh end and an eighth end, The transmitting circuit supplies signals to the second end and the third end, The receiving circuit receives the signal from the sixth end and the signal from the seventh end, The first end is connected to the first terminator. The fourth end is connected to the second terminator. The fifth end is connected to the third terminator. The wireless communication system according to claim 17, characterized in that the eighth end is connected to a fourth terminator.

19. The first transmission line has a first end and a second end, The second transmission line has a third end and a fourth end, The third transmission line has a fifth end and a sixth end, The fourth transmission line has a seventh end and an eighth end, The wireless communication system further includes a connecting portion that connects the fifth end and the seventh end, The transmitting circuit supplies a signal to the sixth end, The receiving circuit receives the signal from the second end and the signal from the third end, The first end is connected to the first terminator. The fourth end is connected to the second terminator. The wireless communication system according to claim 5, characterized in that the eighth end is connected to a fourth terminator.

20. The wireless communication system according to claim 19, characterized in that the receiving circuit has a combiner that combines the signal from the second end and the signal from the third end.

21. The wireless communication system according to claim 20, characterized in that the communication is performed at a frequency below the higher of two frequencies that drop by 1 dB from the peak of the narrowest frequency characteristic among the frequency characteristics of the output signal of the combiner, which changes depending on the moving positions of the third transmission line and the fourth transmission line.

22. The wireless communication system according to claim 1, characterized in that the first transmission line, the second transmission line, the third transmission line, and the fourth transmission line are each single-ended transmission lines.

23. The wireless communication system according to claim 1, characterized in that the first transmission line, the second transmission line, the third transmission line, and the fourth transmission line are each differential transmission lines.

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