Radio communication device, radio communication system, control method and program

Abstract

To correct a propagation delay difference of signals between arcuate two transmission lines in which one transmission line is disposed radially inside and concentrically with respect to the other and one transmission line is shorter than the other.SOLUTION: A radio communication device 10 comprises: a first communication transmission line 101 including a first transmission line 111 consisting of a conductor disposed in an arcuate shape having a predetermined central angle and a second transmission line 112 disposed radially inside of the first transmission line 111 in a shape concentric with the first transmission line 111 and along with a circular arc of the same central angle; and a transmission circuit 106 which is connected to the first and second transmission lines 111 and 112 and inputs signals to the first and second transmission lines 111 and 112. The second transmission line 112 is configured in a meandering shape which corrects a propagation delay difference of signals caused by a transmission line length difference from the first transmission line 111.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a wireless communication device, a wireless communication system, a control method, and a program for performing wireless communication by electromagnetic field coupling. [Background technology]

[0002] In recent years, there have been systems that communicate via rotating parts such as the joints of a robot hand or the camera platform used in a network camera. Wireless communication via such rotating parts has the advantage of enabling infinite rotation and improving maintainability by eliminating the risk of wire breakage. Taking network cameras as an example, the amount of data transmitted via rotating parts is increasing year by year as camera performance improves, and there is a demand for faster data transmission even in wireless systems. For example, Patent Document 1 discloses a wireless communication device that enables contactless data transmission by performing electromagnetic field coupling between a coupler and a differential transmission line arranged in a ring shape for application to a rotating movable part. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 06304906 Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology of the above-mentioned Patent Document 1, two arc-shaped differential transmission lines are wired concentrically and annularly on a dielectric substrate. This configuration is effective for reducing the height of a wireless communication device, but there is a difference in the wiring length between the differential pair. As a result, a difference in propagation delay occurs between the signal flowing through one transmission line of the differential pair and the signal flowing through the other transmission line, which limits the speed of data transmission. Therefore, an object of the present invention is to correct a difference in signal propagation delay between two arc-shaped transmission paths, one of which is arranged concentrically radially inward relative to the other and one of which is shorter than the other. [Means for solving the problem]

[0005] In order to solve the above problem, a wireless communication device according to one embodiment of the present invention is a wireless communication device that performs wireless communication with another wireless communication device by electromagnetic field coupling, and is equipped with a communication transmission path having a first transmission path made of a conductor arranged in an arc shape, and a second transmission path arranged radially inside the first transmission path, concentric with the first transmission path, and made of a conductor arranged in a shape along an arc that is shorter than the first transmission path, and a communication means connected to the first and second transmission paths and inputting a signal to the first and second transmission paths or receiving a signal from the first and second transmission paths, wherein the second transmission path is configured in a meander shape that compensates for the difference in signal propagation delay due to the difference in electrical length with the first transmission path. Effect of the Invention

[0006] According to the present invention, it is possible to correct a difference in signal propagation delay between two arc-shaped transmission paths, one of which is arranged concentrically radially inward relative to the other and one of which is shorter than the other. [Brief description of the drawings]

[0007] [Figure 1] 1 is a diagram showing a schematic configuration example of a wireless communication system according to a first embodiment. [Diagram 2] FIG. 1 is a diagram showing an example of a schematic configuration of a conventional wireless communication system. [Diagram 3] 6 is a timing chart of signals at various positions in a communication transmission line of a conventional shape. [Figure 4] 5 is a timing chart of signals at various positions on a communication transmission line according to the first embodiment. [Figure 5A] FIG. 2 is a perspective view showing a structural example of a communication transmission line according to the first embodiment. [Figure 5B]FIG. 2 is a plan view showing a structural example of a communication transmission line according to the first embodiment. [Figure 5C] Cross-sectional view taken along line CC in FIG. 5A. [Figure 6] 5A to 5C. FIG. 5B is a diagram showing the transfer characteristics of signals in the communication transmission paths shown in FIGS. [Figure 7] 5A to 5C. FIG. 5B is a diagram showing phase characteristics of signals in the communication transmission paths shown in FIGS. [Figure 8] 5A to 5C. FIG. 5B is a diagram showing the phase difference of signals transmitted from the communication transmission paths shown in FIGS. 5A to 5C to a coupler. [Figure 9] 11A and 11B are diagrams showing signal transfer characteristics at design values ​​at different magnitudes of phase difference. [Figure 10] FIG. 13 is a diagram showing an example of a schematic configuration of a wireless communication system according to a second embodiment. [Figure 11] FIG. 13 is a diagram showing an example of a schematic configuration of a wireless communication system according to a third embodiment. [Figure 12] FIG. 13 is a diagram showing an example of a schematic configuration of a wireless communication system according to a fourth embodiment. [Figure 13] FIG. 13 is a diagram showing another example of a schematic configuration of the wireless communication system according to the fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Note that the embodiment described below is one example of a means for realizing the present invention, and should be appropriately modified or changed depending on the configuration of the device to which the present invention is applied and various conditions, and the present invention is not limited to the embodiment described below.

[0009] In addition, in the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the vertical and horizontal dimensions and scales of the members or parts are different from the actual ones. Therefore, the specific dimensions and scales should be determined by taking into consideration the following explanation. In addition, the drawings naturally include parts whose dimensional relationships and ratios differ from one another.

[0010] (First embodiment) First, a first embodiment of the present invention will be described below. Figures 1 to 9 are diagrams showing the first embodiment. FIG. 1 is a diagram showing an example of a schematic configuration of a wireless communication system 1 according to a first embodiment. As shown in FIG. 1, the wireless communication system 1 includes a wireless communication device 10 and a wireless communication device 20. The wireless communication devices 10 and 20 are configured to perform wireless communication using electromagnetic coupling, which includes coupling based on an electric field, coupling based on a magnetic field, and coupling based on both an electric field and a magnetic field.

[0011] [Configuration of wireless communication device 10] First, the configuration of the wireless communication device 10 will be described. The wireless communication device 10 includes communication transmission paths 101 and 101', each of which is formed from a differential transmission path, differential amplifier circuits 105 and 105', and a transmission circuit . The communication transmission lines 101 and 101' are each provided on a dielectric substrate 400 for the purpose of reducing the height (thinning) of the communication transmission lines (see FIGS. 4A, 4B, and 4C).

[0012] The communication transmission line 101 includes a transmission line 111 arranged in an arc shape centered on the rotation axis 30, and a transmission line 112 arranged radially inward from the transmission line 111, concentric with the transmission line 111, and arranged along an arc having the same central angle θ as the transmission line 111. The transmission lines 111 and 112 are each made of a conductor. One end of each of the transmission lines 111 and 112 constitutes a power supply section 102 to which a signal from the differential amplifier circuit 105 is input. The other ends of the transmission lines 111 and 112 , that is, the termination sections 104 , are terminated by termination resistors 114 whose impedances are approximately equal to the characteristic impedances of the transmission lines 111 and 112 , respectively. The communication transmission line 101' is distinguished from the communication transmission line 101 by adding a dash symbol "'" to the same reference symbols (numbers) as those of the communication transmission line 101, but since the same numbers have the same configuration, the description will be omitted. The transmission circuit 106 outputs a signal corresponding to transmission data (hereinafter referred to as a "transmission signal") to each of the differential amplifier circuits 105 and 105'.

[0013] 1, the transmission circuit 106 and the differential amplifier circuits 105 and 105' are typically connected by a single line, but a divider such as a resistive divider or a Wilkinson splitter that divides a high-frequency signal can be inserted. As another means, a fan-out circuit may be used as the differential amplifier circuits 105 and 105'. The differential amplifier circuit 105 converts the transmission signal input from the transmission circuit 106 into a differential signal, and outputs the converted differential signal.

[0014] As a result, a signal of positive potential constituting the differential signal (hereinafter referred to as a “positive differential signal”) is input to power feeder 102 of transmission line 111 via line 121 having impedance 115 that matches the impedance of transmission line 111. On the other hand, a signal of negative potential constituting the differential signal (hereinafter referred to as a “negative differential signal”) is input to power feeder 102 of transmission line 112 via line 122 having impedance 115 that matches the impedance of transmission line 112. The differential amplifier circuit 105' converts the transmission signal input from the transmission circuit 106 into a differential signal, and outputs the converted differential signal.

[0015] As a result, the positive differential signal is input to power feeder 102' of transmission line 111' via line 121' having impedance 115' that matches the impedance of transmission line 111'. On the other hand, the negative differential signal is input to power feeder 102' of transmission line 112' via line 122' having impedance 115' that matches the impedance of transmission line 112'.

[0016] That is, a differential signal plus, which is a differential baseband signal, is input to the power feeders 102 and 102' of the transmission paths 111 and 111' of the communication transmission paths 101 and 101'. On the other hand, a differential signal minus, which is a differential baseband signal, is input to the power feeders 102 and 102' of the transmission paths 112 and 112'. The communication transmission lines 101 and 101' have their power supplying portions 102 and 102' and their terminal ends 104 and 104' disposed close to and facing each other in the circumferential direction, and are configured to be disposed in a substantially circular shape. That is, in the example shown in FIG. 1, transmission lines 111 and 112, and transmission lines 111' and 112' are configured in an arc shape and a shape that follows the arc with a central angle that ensures a gap between the opposing ends of each.

[0017] Moreover, the transmission paths 112 and 112' of the communication transmission paths 101 and 101' are respectively configured in a meander shape. This meander shape is configured to be capable of correcting the influence on communication due to a difference in signal propagation delay caused by a difference in signal electrical length due to a difference in transmission path length (wiring length) between the transmission paths 111 and 112 and an electrical length difference due to a difference in transmission path length between the transmission paths 111' and 112'. Specifically, the meander shape is characterized by the positional relationship between transmission lines 111 and 112, and the positional relationship between transmission lines 111' and 112', the amplitude of the meander, and the period of the meander. It is known that, as a known technique, by inserting meander wiring in a differential transmission line and matching the wiring lengths of the lines, it is possible to correct the difference in signal propagation delay between the lines.

[0018] Furthermore, communication transmission paths 101 and 101' need to be able to ensure coupling that enables communication at all rotation angles with coupler 200 (described later) of wireless communication device 20, which rotates relatively around rotation axis 30. For this reason, power supply units 102 and 102' and terminal units 104 and 104' are arranged close to each other.

[0019] In addition, the meander shapes of the transmission lines 112 and 112' are determined so that the phase of the signal transmitted to the coupler 200 is continuous when the coupler 200 moves or moves relatively across these opposing gaps from the termination 104 to 104' (or vice versa). The same is true when the coupler 200 moves or moves relatively across these gaps from the power feed 102 to 102' (or vice versa).

[0020] [Configuration of wireless communication device 20] Next, the configuration of the wireless communication device 20 will be described. The wireless communication device 20 includes a combiner 200 , a shaping circuit 201 and a receiving circuit 202 . The coupler 200 includes transmission lines 211 and 212 made of conductors, and is configured to be electromagnetically coupled to the communication transmission lines 101 and 101 ′ of the wireless communication device 10 . Specifically, the transmission line 211 is arranged to face the transmission line 111 or 111', and the transmission line 212 is arranged to face the transmission line 112 or 112', with a gap therebetween that allows electromagnetic field coupling in the axial direction.

[0021] Moreover, the transmission paths 211 and 212 are configured to be shorter than the transmission paths 111 and 112, and the transmission paths 111' and 112', of the communication transmission paths 101 and 101', respectively. In addition, the transmission paths 211 and 212 are configured to be arc-shaped to match the shapes of the transmission paths 111 and 112, and the transmission paths 111' and 112'. In the example shown in FIG. 1, communication transmission paths 101 and 101' are configured to rotate in the direction of the arrow in FIG. 1 around the rotation axis of rotation axis center 30, and coupler 200 is configured to move relatively around the rotation axis along communication transmission paths 101 and 101'. In this way, coupler 200 wirelessly and contactlessly receives signals excited by electromagnetic coupling with transmission lines 111 and 112, and transmission lines 111′ and 112′. The received differential signals are output to shaping circuit 201. That is, the wireless communication system 1 is configured to realize wireless communication between the wireless communication device 10 and the wireless communication device 20 by using electromagnetic field coupling. The shaping circuit 201 has a function of amplifying the received waveform to a voltage level that can be detected by the receiving circuit 202 in the subsequent stage. The amplified signal is output to the receiving circuit 202.

[0022] In the first embodiment, the input impedance of the shaping circuit 201 is set to a high impedance Rrp, for example, several tens of kΩ. As a result, the input impedance Rrp is larger even in the low frequency range than the capacitive component generated by the coupling between the communication transmission lines 101 and 101' and the coupler 200, and low frequency band components are also transmitted to the shaping circuit 201. Therefore, the received waveform generated at the input end of the shaping circuit 201 is transmitted while maintaining its rectangular shape. The shaping circuit 201 may have not only an amplification function but also a reclocking function using clock data recovery. The receiving circuit 202 is a circuit that performs a predetermined process based on the signal input from the shaping circuit 201 .

[0023] [Configuration of wireless communication system 1] The wireless communication system 1 has a rotation mechanism (not shown) that rotates the communication transmission paths 101 and 101' around a rotation axis 30 while keeping the coupler 200 and the communication transmission paths 101 and 101' facing each other, and also has a rotation control means (not shown) that controls the rotation operation of the rotation mechanism. Specifically, the rotation mechanism may be, for example, configured to rotate only the wireless communication device 10 side around an axis, or may be configured to rotate the wireless communication device 20 side around an axis as well, or may be configured to rotate only the wireless communication device 20 side around an axis. In the first embodiment, only the wireless communication device 10 is configured to rotate around an axis. With the above configuration, the wireless communication system 1 of the first embodiment can perform wireless communication by electromagnetic field coupling while the coupler 200 rotates relatively along the communication transmission lines 101 and 101'.

[0024] [Explanation of the effect of meandering] Next, the effect of forming the transmission lines 112 and 112' in a meandering shape will be described. FIG. 2 is a diagram showing an example of a schematic configuration of a conventional wireless communication system 1′. 2, a conventional wireless communication system 1' is configured by including a wireless communication device 10' in place of the wireless communication device 10 of the first embodiment in the wireless communication system 1 of the first embodiment. The wireless communication device 10' is configured by including communication transmission paths 107 and 107' in place of the communication transmission paths 101 and 101' of the first embodiment. Specifically, the communication transmission lines 107 and 107' include transmission lines 111 and 112 similar to those in the first embodiment, and transmission lines 113 and 113' having a conventional line shape rather than a meander shape. First, with reference to FIGS. 3(a), (b) and (c), a description will be given of problems that arise when the radially inner transmission lines are transmission lines 113 and 113' having a conventional line shape that is not a meander shape.

[0025] 3(a) to 3(c) are timing charts showing signal waveforms at various positions on communication transmission path 107 when the radially inner transmission path is a conventional transmission path 113. Specifically, Fig. 3(a) is a timing chart of signals at the position of power feeding part 102 in Fig. 2, Fig. 3(b) is a timing chart of signals at the position of central part 103 in Fig. 2, and Fig. 3(c) is a timing chart of signals at the position of terminal part 104 in Fig. 2.

[0026] 3(a) to 3(c), DSIG+ indicates a positive differential signal input to power feeder 102 of transmission line 111, and DSIG- indicates a negative differential signal input to power feeder 102 of transmission line 113. Also, DSIGC in Fig. 3(a) to 3(c) indicates a difference signal between the positive differential signal and the negative differential signal (= positive differential signal - negative differential signal).

[0027] At the position of power supply 102 shown in Fig. 3(a), the phases of DSIG+ and DSIG- are the same. However, if ΔT is the propagation delay difference caused by the difference in electrical length between transmission lines 111 and 113, then a phase shift of ΔT / 2 occurs at the position of center 103 shown in Fig. 3(b), and a phase shift of ΔT occurs at the position of termination 104 shown in Fig. 3(c). This also applies to transmission line 113'. Due to this phase shift, the waveform of the DSIGC becomes distorted as it approaches the termination unit 104, as shown in Figures 3(b) and (c). It can be easily assumed that this phase shift becomes more noticeable as the differential signal speed increases. For the sake of convenience, Figures 3(a) to (c) show a case in which the propagation delay amount ΔT coincides with the time length of one bit of the baseband signal, but this is not limited to the case.

[0028] Next, with reference to FIGS. 4(a), (b) and (c), the effect of forming the radially inner transmission lines 112 and 112' in a meandering shape will be described. 4(a) to 4(c) are timing charts showing signal waveforms at various positions on the communication transmission path 101, in which the radially inner transmission path is the meander-shaped transmission path 112. Note that the transmission path 112' has the same effect as the transmission path 112, so a description thereof will be omitted. 4(a) is a timing chart of the signal at the position of power supply unit 102 in FIG. 1, FIG. 4(b) is a timing chart of the signal at the position of central unit 103 in FIG. 1, and FIG. 4(c) is a timing chart of the signal at the position of terminal unit 104 in FIG.

[0029] 4(a) to 4(c), DSIG+ indicates a positive differential signal input to power feeder 102 of transmission line 111, and DSIG- indicates a negative differential signal input to power feeder 102 of transmission line 112. Also, DSIGC in Fig. 4(a) to 4(c) indicates a difference signal between the positive differential signal and the negative differential signal (= positive differential signal - negative differential signal).

[0030] It can be seen that the phase shift that occurred in the conventional configuration is corrected at all positions, namely the position of the power supply section 102 shown in Fig. 4(a), the position of the central section 103 shown in Fig. 4(b), and the position of the terminal section 104 shown in Fig. 4(c). This makes it possible, in principle, to increase the communication speed compared to the conventional method.

[0031] The meander structure of the transmission lines 112 and 112' is also effective in correcting the propagation delay difference by making part of the transmission lines meander-shaped to match the path length (electrical length) with the transmission lines 111 and 111'. However, in the configuration of the first embodiment in which the transmission lines 211 and 212 of the coupler 200 move along the transmission lines 112 and 112' of the communication transmission lines 101 and 101', it is necessary to correct the same degree of propagation delay no matter where they are moved. In this case, it is desirable to make the entire transmission lines 112 and 112' that are electromagnetically coupled with the transmission lines 211 and 212 into a meander shape.

[0032] [Effects verified through simulation] Fig. 5A is a perspective view showing a specific example of the structure of the communication transmission lines 101 and 101' and the coupler 200. Fig. 5B is a plan view showing a specific example of the structure of the communication transmission lines 101 and 101' and the coupler 200. Fig. 5C is a cross-sectional view taken along line CC in Fig. 5A. The same reference numerals are used for the configurations described in Figs. 1 and 2.

[0033] 5A to 5C, the communication transmission lines 101 and 101' are formed as copper patterns on a dielectric substrate 400. The coupler 200 is disposed at a position a predetermined distance dZ in the Z direction (axial direction) from the upper surfaces of the communication transmission lines 101 and 101'. In other words, dZ is the transmission distance between the communication transmission lines 101 and 101' and the transmission lines 211 and 212.

[0034] The communication transmission lines 101 and 101' are formed of microstrip lines, and a ground pattern 401 made of a conductor is formed on the surface of the communication transmission lines 101 and 101' opposite to the surface on which the line patterns are formed. The ground pattern 401 constitutes a ground that serves as a reference potential for the communication transmission lines 101 and 101'. The communication transmission lines 101 and 101' are not limited to microstrip lines, but may be composed of coplanar lines, coplanar lines with grounds, or the like. Furthermore, the dielectric substrate 400 has a circular hole formed in the center, into which a rotating shaft, an axial slip ring used for power transmission / low-speed communication, or the like is inserted.

[0035] 6(a) and (b) are diagrams showing simulation results of the signal transfer characteristics (S (Scattering) parameter, Sdd21) from the power supply unit 102 of the communication transmission line 101 to the coupler 200 in the structure shown in FIGS. 5A to 5C. In FIGS. 6(a) and 6(b), the horizontal axis indicates frequency and the vertical axis indicates gain. Sdd21 indicates the insertion loss in the differential mode. FIG. 6(a) shows the transfer characteristics when a conventional transmission line 113 is used, and FIG. 6(b) shows the transfer characteristics when a meander-shaped transmission line 112 is used.

[0036] 6(a) and (b) show the transfer characteristics when coupler 200 is relatively moved to the positions of angles 30°, 90°, and 150° shown in Fig. 4(b). In Fig. 6(a) and (b), solid line 610 shows the transfer characteristics at an angle of 30°, dashed line 611 shows the transfer characteristics at an angle of 90°, and dashed line 612 shows the transfer characteristics at an angle of 150°. The parameters used in the simulation are shown in Table 1 below.

[0037] [Table 1]

[0038] As shown in Table 1, the differential impedance of the communication transmission lines 101 and 101' is set to 100Ω, and the characteristic impedance of the transmission lines 111 and 111' and the transmission lines 112 and 112' is set to 50Ω. The differential impedance of the communication transmission lines 107 and 107' is also set to 100Ω, and the characteristic impedance of the transmission lines 111 and 111' and the transmission lines 113 and 113' is also set to 50Ω.

[0039] In the case of the conventional transmission line 113, as shown by the solid line 610 in Fig. 6(a), it can be seen that when the coupler 200 is positioned at an angle of 30° close to the power feeder 102, it has a nearly flat transfer characteristic up to about 5 GHz. On the other hand, as shown by the dashed line 611 and the dashed line 612 in Fig. 6(a), it can be seen that as the coupler 200 moves toward the termination 104 side, toward the angle positions of 90° and 150°, the gain at frequencies above 1 GHz rapidly attenuates. For example, at the angle position of 150°, the gain difference between 1 GHz and 5 GHz widens to about 10 dB. This also applies to the transmission line 113'.

[0040] On the other hand, in the case of the meander-shaped transmission line 112, it can be seen that an approximately flat transfer characteristic is maintained at all angular positions of 30°, 90°, and 150°, as shown by the solid line 610, dashed line 611, and dashed line 612 in Fig. 6(b). For example, at an angle of 150°, the difference in gain between 1 GHz and 5 GHz is only about 1 dB. From the above results, it can be said that by forming the transmission lines 112 and 112' in a meandering shape, the deterioration of the transfer characteristics of high frequency components can be suppressed.

[0041] Figures 7(a), (b) and (c) are diagrams showing simulation results of the phase characteristics of a signal transmitted from power supply unit 102 of communication transmission line 101 to coupler 200 in the structure shown in Figures 5A to 5C. In Figures 7(a) to 7(c), the horizontal axis shows frequency, and the vertical axis shows phase expressed in degrees. Note that the parameters in Table 1 above were also used in this simulation. FIG. 7(a) shows the phase characteristics when coupler 200 is moved relatively to a position at an angle of 30°, FIG. 7(b) shows the phase characteristics when coupler 200 is moved relatively to a position at an angle of 90°, and FIG. 7(c) shows the phase characteristics when coupler 200 is moved relatively to a position at an angle of 150°.

[0042] 7(a) to 7(c), solid lines 701, 711, and 721 indicate the phase characteristics of the signal transmitted from the meander-shaped transmission line 112 to the transmission line 212. Also, dashed lines 702, 712, and 722 indicate the phase characteristics of the signal transmitted from the conventional transmission line 113 to the transmission line 212, and dashed lines 703, 713, and 723 indicate the phase characteristics of the signal transmitted from the transmission line 111 to the transmission line 211.

[0043] In the case of the transmission line 113 of the conventional shape, as shown by the dashed lines 702, 712, and 722 in Figures 7(a) to (c), for example, at 5 GHz, the phase difference is about 40° at an angle of 30°. In addition, the phase difference is about 126° at an angle of 90°, and about 205° at an angle of 150°. In other words, it can be seen that the phase difference increases toward the termination portion 104.

[0044] On the other hand, in the case of the meander-shaped transmission line 112, the phase difference is suppressed to about 9° at an angle of 30° at 5 GHz, as shown by solid lines 701, 711, and 721 in Figures 7(a) to (c). In addition, the phase difference is suppressed to about 34° at an angle of 90°, and to about 52° at an angle of 150°. From the above results, it can be said that by forming the transmission line 112 in a meandering shape, it is possible to suppress the phase difference in the entire communication transmission line 101. The same is true for the communication transmission line 101'.

[0045] [Meander shape design] Next, the design of the meander shape of the transmission lines 112 and 112' will be described. Although only the design of the transmission line 112 will be described, the meander shapes of the transmission line 112 and the transmission line 112' are similarly designed. An example will be described in which the inner diameter A of the transmission line 111 is 50 mm, the wiring width W is 4 mm, and the operating center frequency is 5 GHz. Figure 8(a) is a diagram showing the phase difference between a signal transmitted from transmission line 111 to 211 and a signal transmitted from transmission line 112 to 212, with respect to the ratio of the inner diameter B of transmission line 112 to the inner diameter A of transmission line 111 and the ratio of the meander width Wm of transmission line 112 to the inner diameter A.

[0046] 8(a), inner diameter A is the linear distance between rotation axis 30 and a center line passing through the widthwise center of transmission line 111, and inner diameter B is the linear distance between rotation axis 30 and a center line passing through the widthwise center of transmission line 112. Also, the phase difference at an operating center frequency of 5 GHz is shown in a color map.

[0047] In FIG. 8(a), the design parameters of the transmission line 112 are an inner diameter A of the transmission line 111 of 50 mm, a wiring width W of 4 mm, and a meander number N of 200. The dotted lines in FIG. 8(a) indicate the boundary where the phase difference is 90° and the boundary where the phase difference is -90°. The inner diameter B of the transmission line 112 and the meander width Wm of the transmission line 112 are designed in a range in which the phase difference is as small as possible in FIG. 8(a). Specifically, it has been experimentally found that the meander width Wm that minimizes the phase difference is 50 to 75% of the wiring width W when the wiring width W is in the range of 3.9 to 5.5 mm. Figure 8(b) is a diagram showing the phase difference between the signal transmitted from transmission path 111 to 211 and the signal transmitted from transmission path 112 to 212, versus the number of meanders N per unit angle and the ratio of meander width Wm to inner diameter A when inner diameter B is 40 mm.

[0048] In Fig. 8(b), the phase difference at an operating center frequency of 5 GHz is shown in a color map. In Fig. 8(b), the design parameters of the transmission line 112 are an inner diameter A of the transmission line 111 of 50 mm, an inner diameter B of the transmission line 112 of 40 mm, and a wiring width W of 4 mm. The dotted lines in Fig. 8(b) indicate the boundary line where the phase difference is 90° and the boundary line where the phase difference is -90°. The number of meanders N per unit angle and the meander width Wm of the transmission line 112 are designed in a range where the phase difference in Fig. 8(b) is as small as possible.

[0049] As described above, the meander shape of the transmission line 112 is designed to minimize the phase difference at the center frequency between the signal transmitted from the transmission line 111 to the transmission line 211 and the signal transmitted from the transmission line 112 to the transmission line 212. This makes it possible to suppress the deterioration of the transfer characteristics up to the center frequency.

[0050] Fig. 9(a) is a diagram showing the simulation results of the transfer characteristics of a signal from the power feeding point 102 of the communication transmission line 101 to the coupler 200, for design values ​​at the position of point 701 where the phase difference is small in Fig. 8(b). In Fig. 9(a), the horizontal axis represents frequency, and the vertical axis represents gain.

[0051] 9(a) shows the transfer characteristics when coupler 200 is moved to positions with angles of 30°, 90°, and 150°. In FIG. 9(a), solid line 911 shows the transfer characteristics at an angle of 30°, dashed line 912 shows the transfer characteristics at an angle of 90°, and dashed line 913 shows the transfer characteristics at an angle of 150°. The design parameters of the transmission line 112 at point 701 in FIG. 8(b) are: inner diameter A of the transmission line 111 is 50 mm; inner diameter B of the transmission line 112 is 40 mm; meander width Wm of the transmission line 112 is 2.5 mm; wiring width W is 4 mm; and number of meanders N is 120.

[0052] In this way, when the meander shape is designed to reduce the phase difference, the transfer characteristics are as shown by the solid line 911, the dashed line 912, and the dashed line 913 in Fig. 9(a). That is, at all angle positions of 30°, 90°, and 150°, the transfer characteristics are maintained approximately flat up to a center frequency of 5 GHz.

[0053] On the other hand, Fig. 9(b) is a diagram showing the simulation results of the transfer characteristics of the signal from the power supply unit 102 of the communication transmission line 101 to the coupler 200, for the design values ​​at the position of the point 702 where the phase difference is large in Fig. 8(b). In Fig. 9(b), the horizontal axis indicates the frequency, and the vertical axis indicates the gain.

[0054] 9(b) shows the transfer characteristics when coupler 200 is moved to positions with angles of 30°, 90°, and 150°. In FIG. 9(b), solid line 911 shows the transfer characteristics at an angle of 30°, dashed line 912 shows the transfer characteristics at an angle of 90°, and dashed line 913 shows the transfer characteristics at an angle of 150°. The design parameters of the transmission line 112 at point 702 in FIG. 8(b) are: inner diameter A of the transmission line 111 is 50 mm; inner diameter B of the transmission line 112 is 40 mm; meander width Wm of the transmission line 112 is 3.5 mm; wiring width W is 4 mm; and number of meanders N is 140.

[0055] In this way, when the meander shape is designed to increase the phase difference, the transmission characteristics are approximately flat up to about 5 GHz at an angle of 30°, as shown by the solid line 911 in Fig. 9(b). On the other hand, as shown by the dashed line 912 and the dashed line 913 in Fig. 9(b) as the coupler 200 moves toward the termination unit 104 at angles of 90° and 150°, the gain at 5 GHz attenuates.

[0056] From the above simulation results, it can be said that it is desirable to design the meander shape of the transmission line 112 so that the phase difference at the center frequency between the signal transmitted from the transmission line 111 to the transmission line 211 and the signal transmitted from the transmission line 112 to the transmission line 212 is as small as possible. In other words, by adopting this design, it is possible to suppress the deterioration of the transmission characteristics up to the vicinity of the center frequency. Note that the wiring width W may be adjusted to such an extent that the differential impedance and the characteristic impedance do not change. In the first embodiment, the input impedance Rrp of the shaping circuit 201 is set to a high impedance of several tens of kΩ, but this is not limited to this. For example, it may be set to a low impedance such as 100Ω.

[0057] In this case, the transfer characteristic from the communication transmission paths 101 and 101' to the coupler 200 is similar to that of an HPF (high pass filter) in which the degree of coupling is weak in low frequency bands and strong in high frequency bands. Therefore, only high frequency components are transferred from the communication transmission paths 101 and 101' to the coupler 200.

[0058] Specifically, an imperfect differential waveform (an edge signal generated at the rising and falling edges of the baseband signal input to the communication transmission paths 101 and 101') of the signal input to the communication transmission paths 101 and 101' is generated in the coupler 200. Therefore, the shaping circuit 201 is not a simple amplifier circuit, but needs to use a circuit for restoring this differential waveform to a binary baseband signal of "1" and "0", such as a hysteresis comparator.

[0059] In the first embodiment, the wireless communication device 10 is configured such that the two communication transmission paths 101 and 101' are arranged along an arc of a substantial semicircle in a substantial circular shape, but the configuration is not limited to this. For example, three or more communication transmission paths with a central angle smaller than that of the communication transmission paths 101 and 101' may be arranged in a substantial circular shape while ensuring opposing gaps.

[0060] In the first embodiment, communication transmission paths 101 and 101' are configured in an arc shape centered on rotation axis 30, but the configuration is not limited to this. As long as the opposing state with coupler 200 can be maintained, other configurations may be used, such as a configuration in which two communication transmission paths formed in a semicircular arc shape (central angle 180°) centered on rotation axis 30 are uniformly shifted from each other from rotation axis 30 by the opposing gap.

[0061] In the first embodiment, the transmission lines 111 and 112, and the transmission lines 111' and 112' are each configured to have a shape along a concentric circular arc with the same central angle, but this is not the only possible configuration. For example, the transmission lines 112 and 112' may have a different central angle as long as they are configured to have a shape along a circular arc that is shorter than the transmission lines 111 and 111'. More specifically, it is sufficient that the transmission lines 112 and 112' are configured to be shorter than the transmission lines 111 and 111' when they are transmission lines of a conventional shape.

[0062] As described above, the wireless communication system 1 according to the first embodiment is configured to perform wireless communication by electromagnetic field coupling between the wireless communication device 10 on the transmitting side and the wireless communication device 20 on the receiving side. In addition, the communication transmission paths 101 and 101' of the wireless communication device 10 are configured as differential transmission paths, and the transmission paths 111 and 111' are configured to be arranged in an arc shape having a central angle that is a substantially semicircular arc. Furthermore, the transmission paths 112 and 112' are configured to be arranged radially inward of the transmission paths 111 and 111', and to be arranged in a shape along an arc concentric with the transmission paths 111 and 111' and having the same central angle. Furthermore, the transmission paths 112 and 112' are configured in a meander shape that corrects the signal propagation delay difference caused by the electrical length difference caused by the transmission path length difference between the transmission paths 111 and 111'.

[0063] With this configuration, the difference in propagation delay of the differential signal between each pair of transmission lines can be corrected, and therefore a wireless communication system capable of high-speed wireless communication of the differential signal can be provided, compared to a case in which the transmission lines 112 and 112' are configured with transmission lines of a conventional shape. Also, by simply forming the transmission lines 112 and 112' into a meandering shape, the difference in transmission delay can be corrected without adding additional circuit components for correction, which facilitates the reduction in height and size of the device. Furthermore, in the wireless communication system 1 according to the first embodiment, the communication transmission paths 101 and 101' are configured to have a shape that follows an arc centered on the rotation axis 30, and therefore, application to a rotating movable part is easy.

[0064] Moreover, in the wireless communication system 1 according to the first embodiment, the communication transmission lines 101 and 101' are configured to be wired by a copper pattern on the dielectric substrate 400. This enables the wireless communication device 10 to be made low-profile (thin). That is, since the transmission delay difference can be corrected by making the wiring patterns of the transmission lines 112 and 112' meandering, it is possible to easily configure them on the dielectric substrate 400, and since no additional components are required, it is easy to make the device low-profile.

[0065] (Second embodiment) Next, a second embodiment of the present invention will be described with reference to Fig. 10, which shows the second embodiment. The second embodiment differs from the first embodiment in that a signal is transmitted from a coupler 200 to communication transmission paths 101 and 101'. Hereinafter, the same components as those described in the first embodiment will be denoted by the same reference numerals and the description thereof will be omitted as appropriate, and only the parts that differ from the first embodiment will be described in detail.

[0066] FIG. 10 is a diagram illustrating an example of a schematic configuration of a wireless communication system 2 according to the second embodiment. As shown in FIG. 10, the wireless communication system 2 includes a wireless communication device 11 and a wireless communication device . The wireless communication device 11 includes communication transmission paths 101 and 101 ′ configured from differential transmission paths, shaping circuits 117 and 117 ′, and a receiving circuit 118 . The wireless communication device 21 includes a coupler 200 , a differential amplifier circuit 213 and a transmission circuit 214 . The communication transmission lines 101 and 101' are provided on a dielectric substrate for the purpose of reducing the height, as in the first embodiment. The specific structure is the same as in Figs. 5A to 5C. Also, similarly to the first embodiment described above, a rotation mechanism (not shown) and a rotation control means (not shown) are provided that rotate the coupler 200 relatively around a rotation axis whose center of rotation is the rotation axis center 30 while maintaining the coupler 200 and the communication transmission paths 101 and 101' facing each other.

[0067] First, each component of the wireless communication device 21 will be described. The transmission circuit 214 outputs the transmission signal to the differential amplifier circuit 213 . The differential amplifier circuit 213 converts the data transmitted from the transmission circuit 214 into a differential signal, and outputs it to the coupler 200 . The coupler 200 has the same configuration and function as the first embodiment, and therefore the description thereof will be omitted. A differential signal plus is input from the differential amplifier circuit 213 to the transmission line 211, and a differential signal minus is input to the transmission line 212, respectively. Next, each component of the wireless communication device 11 will be described. Here, the communication transmission paths 101 and 101' have the same configuration and functions as those in the first embodiment, and therefore the description thereof will be omitted.

[0068] The shaping circuits 117 and 117' are connected to the communication transmission lines 101 and 101' via lines 121 and 122, and lines 121' and 122', respectively. The shaping circuits 117 and 117' shape the waveform of the signal transmitted from the coupler 200 to the communication transmission lines 101 and 101' by electromagnetic coupling into a signal waveform that can be received by the receiving circuit 118 at the subsequent stage, and output the signal.

[0069] In the second embodiment, the inputs of the shaping circuits 117 and 117' are provided with termination resistors 116 and 116' that are approximately equal to the characteristic impedance of the communication transmission lines 101 and 101'. The lines 121 and 121' are also wired with a characteristic impedance that is approximately equal to the characteristic impedance of the communication transmission lines 101 and 101'.

[0070] Therefore, the transfer characteristic from the coupler 200 to the communication transmission paths 101 and 101' resembles that of an HPF (high pass filter) in which the degree of coupling is weak in low frequencies and strong in high frequencies. Therefore, only high frequency components are transferred from the coupler 200 to the communication transmission paths 101 and 101'. Specifically, an incomplete differential waveform of the signal input to the coupler 200 occurs in the communication transmission paths 101 and 101'. Therefore, the shaping circuits 117 and 117' in the second embodiment are configured by a circuit for restoring this differential waveform to a binary baseband signal of "1" and "0", for example, a hysteresis comparator.

[0071] In the second embodiment, as in the first embodiment, the transmission lines 112 and 112' are configured in a meander shape. By making the transmission lines 112 and 112' in a meander shape, it is possible to suppress the influence on communication caused by the propagation delay difference caused by the electrical length difference (wiring length difference) between the transmission lines 111 and 112 (or the transmission lines 111' and 112'). Note that the design of the meander shape is the same as in the first embodiment, so a description thereof will be omitted.

[0072] As described above, the wireless communication system 2 according to the second embodiment is configured to perform wireless communication by electromagnetic field coupling between the wireless communication device 11 on the receiving side and the wireless communication device 21 on the transmitting side. In addition, the communication transmission paths 101 and 101' of the wireless communication device 11 are configured as differential transmission paths, and the transmission paths 111 and 111' are configured to be arranged in an arc shape having a central angle that is a substantially semicircular arc. Furthermore, the transmission paths 112 and 112' are configured to be arranged radially inward of the transmission paths 111 and 111', and to be arranged in a shape along an arc concentric with the transmission paths 111 and 111' and having the same central angle. Furthermore, the transmission paths 112 and 112' are configured in a meander shape that corrects the signal propagation delay difference caused by the electrical length difference caused by the transmission path length difference between the transmission paths 111 and 111'.

[0073] With this configuration, the difference in propagation delay of the differential signal between each pair of transmission lines can be corrected, and therefore a wireless communication system capable of high-speed wireless communication of the differential signal can be provided, compared to a case in which the transmission lines 112 and 112' are configured with transmission lines of a conventional shape. Also, by simply forming the transmission lines 112 and 112' into a meandering shape, the difference in transmission delay can be corrected without adding additional circuit components for correction, which facilitates the reduction in height and size of the device. Furthermore, in the wireless communication system 2 according to the second embodiment, the communication transmission paths 101 and 101' are configured to have a shape that follows an arc centered on the rotation axis 30, and therefore, application to a rotating movable part is easy.

[0074] Moreover, in the wireless communication system 2 according to the second embodiment, the communication transmission lines 101 and 101' are configured to be wired on the dielectric substrate 400. This enables the wireless communication device 11 to be made low-profile (thin). That is, since the transmission delay difference can be corrected by forming the wiring patterns of the transmission lines 112 and 112' in a meandering shape, it is possible to easily configure the lines on the dielectric substrate 400, and since no additional components are required, the wireless communication device 11 can be easily made low-profile.

[0075] (Third embodiment) Next, a third embodiment of the present invention will be described with reference to Fig. 11, which shows the third embodiment. The third embodiment differs from the first embodiment in that parallel signals are transmitted from the communication transmission paths 101 and 101 ′ of the wireless communication device 12 to the coupler 200 of the wireless communication device 20 . Hereinafter, the same components as those described in the first embodiment will be denoted by the same reference numerals and the description thereof will be omitted as appropriate, and only the parts that differ from the first embodiment will be described in detail. FIG. 11 is a diagram illustrating an example of a schematic configuration of a wireless communication system 3 according to the third embodiment.

[0076] The wireless communication system 3 is a wireless communication system that transmits two different parallel signals simultaneously in parallel. The wireless communication system 3 is configured such that transmission lines that transmit parallel signals are installed on a dielectric substrate. That is, the skew (time difference between signals arriving at the receiving circuit 221) caused by the electrical length difference due to the transmission line length difference of each coupling transmission line is improved based on the same idea as in the first embodiment. The wireless communication system 3 includes a wireless communication device 12 and a wireless communication device 22, as shown in FIG. The wireless communication device 12 includes communication transmission paths 101 and 101', amplifier circuits 123_1 and 123-2, amplifier circuits 123'_1 and 123'_2, and a transmission circuit . The wireless communication device 22 includes a combiner 200, shaping circuits 220_1 and 220_2, and a receiving circuit 221. The transmission lines 111 and 111' and the transmission lines 112 and 112' are provided on the same dielectric substrate for the purpose of reducing the height, as in the first embodiment. The specific structure is the same as in FIG. Hereinafter, in the third embodiment, for convenience of explanation, the transmission lines 211 and 212 of the coupler 200 will be referred to as couplers 211 and 212.

[0077] Also, similarly to the above-described first embodiment, coupler 211 and transmission lines 111 and 111', and transmission line 212 and transmission lines 112 and 112' rotate relatively around a rotation axis whose center of rotation is rotation axis 30 while maintaining an opposing state. For this reason, wireless communication system 3 includes a rotation mechanism (not shown) and a rotation control means (not shown). First, each component of the wireless communication device 12 will be described. The transmission circuit 124 has output terminals CH1 and CH2, and outputs two parallel signals simultaneously in parallel from these two output terminals CH1 and CH2.

[0078] The amplifier circuits 123_1 and 123'_1 amplify the data signal output from the output terminal CH1 of the transmission circuit 124 as a single-ended signal, and output the signal to the transmission paths 111 and 111' via the lines 121 and 121'. Similarly, the amplifier circuits 123_2 and 123'_2 amplify the data signal output from the output terminal CH2 of the transmission circuit 124 as a single-ended signal, and output the signal to the transmission paths 112 and 112' via the lines 122 and 122'. Note that the transmission paths 111 and 111' and the transmission paths 112 and 112' have the same configurations and functions as those in the first embodiment, and therefore description thereof will be omitted.

[0079] Next, each component of the wireless communication device 22 will be described. Here, the couplers 211 and 212 have the same configuration and function as the transmission lines 211 and 212 in the first embodiment, and therefore a description thereof will be omitted. The shaping circuits 220_1 and 220_2 each have a function similar to that of the shaping circuit 201 of the first embodiment described above, and each input impedance is set to a high impedance Rrp of several kΩ to several tens of kΩ, as in the first embodiment described above.

[0080] As a result, the input impedance Rrp is larger even in the low frequency range than the capacitance components generated by the coupling between the transmission lines 111 and 111' and the coupler 211 and the transmission lines 112 and 112' and the coupler 212. Therefore, the components in the low frequency band are also transmitted to the shaping circuits 220_1 and 220_2. As a result, the received waveforms generated at the input ends CH1' and CH2' of the shaping circuits 220_1 and 220_2 are transmitted while maintaining their rectangular shapes.

[0081] Moreover, the shaping circuits 220_1 and 220_2 have a function of amplifying the received waveform to a voltage level detectable by the downstream receiving circuit 221. The shaping circuits 220_1 and 220_2 may be configured to have not only an amplification function but also a reclocking function using clock data recovery.

[0082] The receiving circuit 221 has input terminals CH1' and CH2' which are input terminals for signals output from the output terminals CH1 and CH2. The input terminal CH1' receives the output signal from the shaping circuit 220_1, and the input terminal CH2' receives the output signal from the shaping circuit 220_2. The receiving circuit 221 performs a predetermined process based on the signals input from the shaping circuits 201_1 and 201_2.

[0083] In the third embodiment, as in the first embodiment, the transmission lines 112 and 112' are configured in a meander shape. By forming the transmission lines 112 and 112' in a meander shape, it is possible to suppress skew between parallel signals caused by a propagation delay difference that occurs due to an electrical length difference caused by a wiring length difference between the transmission lines 111 and 112. As a result, the improvement in skew makes it possible to increase the speed of parallel signals compared to the conventional art. Note that the design of the meander shape is the same as in the first embodiment, so a description thereof will be omitted.

[0084] As described above, the wireless communication system 3 of the third embodiment is configured to perform wireless communication by electromagnetic field coupling between the wireless communication device 12 on the transmitting side and the wireless communication device 22 on the receiving side. In addition, the communication transmission paths 101 and 101' of the wireless communication device 12 are configured as transmission paths that transmit parallel signals, and the transmission paths 111 and 111' are configured to be arranged in an arc shape having a central angle that is a substantially semicircular arc. Furthermore, the transmission paths 112 and 112' are configured to be arranged radially inward of the transmission paths 111 and 111', and to be arranged in a shape along an arc that is concentric with the transmission paths 111 and 111' and has the same central angle. Furthermore, the transmission paths 112 and 112' are configured in a meander shape that corrects the signal propagation delay difference caused by the electrical length difference caused by the transmission path length difference between the transmission paths 111 and 111'.

[0085] With this configuration, the propagation delay difference of the parallel signals between each pair of transmission lines can be corrected, so a wireless communication system capable of high-speed wireless communication of parallel signals can be provided, compared to a case in which transmission lines 112 and 112' are configured with transmission lines of a conventional shape. Also, by simply making the shape of transmission lines 112 and 112' meandering, the transmission delay difference can be corrected without adding additional circuit components for correction, so that it is easy to reduce the height and size of the device. Furthermore, in the wireless communication system 3 of the third embodiment, the communication transmission paths 101 and 101' are configured to have a shape that follows an arc centered on the rotation axis 30, and therefore, application to a rotating movable part is easy.

[0086] Moreover, in the wireless communication system 3 of the third embodiment, the communication transmission lines 101 and 101' are configured to be wired on the dielectric substrate 400, which enables a low profile (thinning) of the wireless communication device 12. That is, the transmission delay difference can be corrected by forming the wiring patterns of the transmission lines 112 and 112' in a meandering shape, so that the transmission lines can be easily configured on the dielectric substrate 400, and additional components are not required, so that the wireless communication device 12 can be easily made low profile. [Configuration for 3 channels] In the third embodiment, for convenience of explanation, a case where two-channel parallel signals are transmitted has been described, but the present invention is not limited to this and can be applied to a case where three or more channels are transmitted. For example, a case where three channels are transmitted will be described.

[0087] In the case of three channels, three lanes of transmission lines are arranged in an arc shape or along an arc centered on the rotation axis. Hereinafter, the transmission line arranged on the outermost circumference is referred to as the first transmission line, the transmission line arranged on the innermost circumference as the third transmission line, and the transmission line arranged between the first and third transmission lines as the second transmission line. The first transmission line does not have a meander structure, but is arranged in an arc shape centered on the rotation axis. The second and third transmission lines each have a meander shape, and are arranged along an arc with the same central angle as the first transmission line, centered on the rotation axis.

[0088] The second transmission line has a meander structure that corrects the propagation delay difference with the first transmission line. The meander structure of the third coupling transmission line has a meander structure that corrects the propagation delay difference with the first and second transmission lines. In other words, the closer the coupling transmission line is to the center of the rotation axis, the larger the propagation delay difference to be corrected, so the meander width and the number of meanders are designed to be larger.

[0089] In the third embodiment, each parallel signal is described as a single-ended signal, but it may be a differential signal. In that case, the transmission path is configured with two transmission paths per channel, similar to the communication transmission paths 101 and 101' in the first embodiment. In that case, the design of each transmission path is the same as the design for the three channels described above.

[0090] In the third embodiment, a wireless communication system in which a signal is transmitted from wireless communication device 12 to wireless communication device 22 has been described, but a configuration in which a signal is transmitted from wireless communication device 22 to wireless communication device 12 may also be used. In this case, the same idea as in changing the configuration from the first embodiment to the second embodiment is applied.

[0091] (Fourth embodiment) Next, a fourth embodiment of the present invention will be described below with reference to Figures 12 and 13, which show the fourth embodiment. The fourth embodiment differs from the first embodiment in that some of the components of the wireless communication device on the transmitting side are omitted. Hereinafter, the same components as those described in the first embodiment will be denoted by the same reference numerals and the description thereof will be omitted as appropriate, and only the parts that differ from the first embodiment will be described in detail. FIG. 12 is a diagram showing an example of a schematic configuration of a wireless communication system 4 according to the fourth embodiment.

[0092] The wireless communication system 4 is configured by excluding the communication transmission path 101', the differential amplifier circuit 105', the lines 121' and 122', and the termination resistor 104' from the wireless communication system 1 of the first embodiment. In addition, the wireless communication system 4 is configured to include a communication transmission path 101A instead of the communication transmission path 101 of the first embodiment.

[0093] The communication transmission path 101A includes a transmission path 111A arranged in a semicircular arc centered on the rotation axis 30, and a transmission path 112A arranged radially inside the transmission path 111A and arranged along an arc concentric with and with the same central angle as the transmission path 111A. In other words, since there is no need to consider the opposing gap with other communication transmission paths, the transmission path 112A can be arranged along an arc with a central angle of 180°.

[0094] The communication transmission path 101A is provided on a dielectric substrate for the purpose of reducing the height (thinning), for example. That is, the communication transmission path 101A is configured by removing the communication transmission path 101′ from the dielectric substrate 400 in FIGS. 5A to 5C, and providing the transmission paths 111A and 112A of the communication transmission path 101A in a shape along an arc having a central angle of 180°.

[0095] The wireless communication system 4 is configured so that the coupler 200 and the communication transmission line 101A rotate relatively back and forth about the rotation axis 30 within an angle range of 0° to 180°, which is a section in which the coupler 200 and the communication transmission line 101A can maintain an opposing state. For this reason, the wireless communication system 4 includes a rotation mechanism (not shown) and a rotation control means (not shown). The wireless communication device 13 in the fourth embodiment is suitable for application to a rotary movable part that is premised on reciprocal rotation (wherein infinite rotation is not required), such as the tilt part of a pan-tilt camera.

[0096] As described above, the wireless communication system 4 according to the fourth embodiment is configured to perform wireless communication by electromagnetic field coupling between the wireless communication device 13 on the transmitting side and the wireless communication device 20 on the receiving side. In addition, the communication transmission path 101A of the wireless communication device 13 is configured as a differential transmission path, and the transmission path 111A is configured to be arranged in an arc shape having a central angle (180°) that is a semicircular arc. Furthermore, the transmission path 112A is configured to be arranged radially inside the transmission path 111A and to be arranged in a shape along an arc concentric with the transmission path 111A and having the same central angle. Furthermore, the transmission path 112A is configured in a meander shape that corrects the signal propagation delay difference caused by the electrical length difference caused by the transmission path length difference with the transmission path 111A.

[0097] With this configuration, the propagation delay difference of the differential signals between the transmission lines 111A and 112A can be corrected, and therefore a wireless communication system capable of high-speed wireless communication of differential signals can be provided, compared to a case in which the transmission line 112A is configured with a transmission line of a conventional shape. Also, by simply forming the shape of the transmission line 112A into a meander shape, the transmission delay difference can be corrected without adding additional circuit components for correction, and therefore it is easy to reduce the height and size of the device. Furthermore, in the wireless communication system 4 according to the fourth embodiment, the communication transmission path 101A is configured in a shape that follows an arc centered on the rotation axis 30, making it easy to apply to a rotating movable part having a rotation range of 0° to 180°.

[0098] Moreover, in the wireless communication system 4 according to the fourth embodiment, the communication transmission line 101A is configured to be wired on a dielectric substrate. This allows the wireless communication device 13 to be made low-profile (thin). That is, since the transmission delay difference can be corrected by making the wiring pattern of the transmission line 112A meandering, it is possible to easily configure it on a dielectric substrate, and since no additional components are required, it is easy to make it low-profile.

[0099] In the fourth embodiment, the rotation angle range of the rotation mechanism is set to a range of 0° to 180°, but is not limited thereto, and can be set to any angle by adjusting the transmission path length of the communication transmission path 101A. As a specific example, a configuration in which the transmission paths are arranged in a shape along a substantially circular arc will be described below. FIG. 13 is a diagram showing a schematic configuration of a wireless communication system 5 according to a modified example of the fourth embodiment. As shown in FIG. 13, the wireless communication system 5 includes a wireless communication device 14 and a wireless communication device 20. The wireless communication device 14 includes a communication transmission path 101B formed of a differential transmission path, a differential amplifier circuit 105, and a transmission circuit . The communication transmission line 101B is provided on a dielectric substrate, for example, for the purpose of reducing the height (thinning).

[0100] The communication transmission line 101B includes a transmission line 111B arranged in a substantially circular arc shape (for example, an arc with a central angle of 350°) centered on the rotation axis 30. In addition, the communication transmission line 101B includes a transmission line 112B arranged radially inward from the transmission line 111B, concentric with the transmission line 111B, and arranged along an arc with the same central angle. The transmission lines 111B and 112B are made of conductors. One end of each of the transmission lines 111B and 112B constitutes a power supply section 102B to which a signal from the differential amplifier circuit 105 is input. The other ends of the transmission lines 111B and 112B, that is, termination sections 104B, are terminated by termination resistors 114 having substantially the same characteristic impedance as the transmission lines 111B and 112B, respectively.

[0101] In the communication transmission path 101B, the power supply unit 102B and the terminal end 104B of the transmission path 111B, and the power supply unit 102B and the terminal end 104B of the transmission path 112B are arranged close to each other in the circumferential direction and facing each other. Moreover, the transmission path 112B of the communication transmission path 101B is formed in a meander shape.

[0102] Differential amplifier circuit 105 converts the transmission signal input from transmission circuit 106 into a differential signal, and outputs a positive differential signal and a negative differential signal. The positive differential signal is input to power feeder 102B of transmission line 111B via line 121 having impedance 115 that matches the impedance of transmission line 111B. On the other hand, the negative differential signal is input to power feeder 102B of transmission line 112B via line 122 having impedance 115 that matches the impedance of transmission line 112B.

[0103] The wireless communication system 5 rotates relatively around a rotation axis having the rotation axis 30 as the center of rotation, while maintaining the coupler 200 and the communication transmission line 101B facing each other. Therefore, the wireless communication system 5 includes a rotation mechanism (not shown) and a rotation control means (not shown) similarly to the first embodiment.

[0104] Moreover, in wireless communication system 5, coupler 200 receives signals while moving relatively around the rotation axis in the range of 0° to 360° while maintaining the opposing state with transmission lines 111B and 112B. Therefore, coupler 200 moves from one side to the other across the opposing gap between power supply unit 102B and termination unit 104B, causing a delay in the transmission signal between the two sides. Therefore, a correction means for correcting this delay may be separately provided.

[0105] As described above, the wireless communication system 5 according to the modification of the fourth embodiment is configured to perform wireless communication by electromagnetic field coupling between the wireless communication device 14 on the transmitting side and the wireless communication device 20 on the receiving side. In addition, the communication transmission path 101B of the wireless communication device 14 is configured as a differential transmission path, and the transmission path 111B is configured to be arranged in an arc shape having a central angle that is a substantially semicircular arc. Furthermore, the transmission path 112B is configured to be arranged radially inward from the transmission path 111B, and is configured to be arranged in a shape along an arc concentric with the transmission path 111B and having the same central angle. Furthermore, the transmission path 112B is configured in a meander shape that corrects the signal propagation delay difference caused by the electrical length difference caused by the transmission path length difference with the transmission path 111B.

[0106] With this configuration, the propagation delay difference of the differential signals between the transmission lines 111B and 112B can be corrected, and therefore a wireless communication system capable of high-speed wireless communication of differential signals can be provided, compared to a case in which the transmission line 112B is configured with a transmission line of a conventional shape. Also, by simply forming the shape of the transmission line 112B into a meander shape, the transmission delay difference can be corrected without adding additional circuit components for correction, which facilitates the reduction in height and size of the device. Furthermore, in the wireless communication system 5 according to the modification of the fourth embodiment, the communication transmission line 101B is configured to have a shape that follows an arc centered on the rotation axis 30, and therefore, it is easy to apply the system to a rotating movable part.

[0107] Moreover, in the wireless communication system 5 according to the modified example of the fourth embodiment, the communication transmission line 101B is configured to be wired on a dielectric substrate. This allows the wireless communication device 14 to be made low-profile (thin). That is, since the transmission delay difference can be corrected by making the wiring pattern of the transmission line 112B meandering, it is possible to easily configure it on a dielectric substrate, and since no additional components are required, it is easy to make it low-profile. (Other embodiments)

[0108] The present invention can be embodied as, for example, a system, an apparatus, a method, a program, or a recording medium (storage medium), etc. Specifically, the present invention may be applied to a system composed of multiple devices (for example, a host computer, an interface device, a Web application, etc.), or may be applied to an apparatus composed of a single device.

[0109] The present invention can also be realized by supplying a program for realizing one or more of the functions of the above-described embodiments to a system or device via a network or a recording medium, and having one or more processors in a computer of the system or device read and execute the program. The present invention can also be realized by a circuit (e.g., ASIC) that realizes one or more of the functions. The disclosure of the above embodiment includes the following configurations and methods. (Configuration 1) A wireless communication device that performs wireless communication with another wireless communication device by electromagnetic field coupling, a communication transmission line including a first transmission line made of a conductor arranged in an arc shape, and a second transmission line arranged radially inside the first transmission line, concentric with the first transmission line, and made of a conductor arranged in a shape along a circular arc that is shorter than the first transmission line; a communication means connected to the first and second transmission paths and configured to input a signal to the first and second transmission paths or receive a signal from the first and second transmission paths; A wireless communication device, wherein the second transmission path is configured in a meandering shape that compensates for a difference in signal propagation delay due to a difference in electrical length with the first transmission path.

[0110] (Configuration 2) In claim 1, The wireless communication device, wherein the second transmission path is arranged along a circular arc that is concentric with and has the same central angle as the first transmission path. (Configuration 3) In configuration 1 or 2, A wireless communication device characterized in that the second transmission path is configured in a meandering shape so that a signal phase difference caused by the difference between the electrical length from one end to the other end of the first transmission path and the electrical length from one end to the other end of the second transmission path is 90° or less in order to correct the propagation delay difference.

[0111] (Configuration 4) In any one of configurations 1 to 3, A plurality of the communication transmission paths are provided, A wireless communication device characterized in that the multiple communication transmission paths are each arranged at a predetermined interval in the circumferential direction, and each two of the communication transmission paths adjacent to each other in the circumferential direction are arranged such that one end of the first and second transmission paths of one of the paths and the other end of the first and second transmission paths of the other path, or one end or the other end of the first and second transmission paths of both paths are arranged closely adjacent to and facing each other in the circumferential direction. (Configuration 5) In any one of configurations 1 to 4, the communication transmission line has at least one third transmission line made of a conductor arranged radially inside the second transmission line, concentric with the second transmission line, and shaped along a circular arc shorter than the second transmission line; A wireless communication device characterized in that, in one case, the at least one third transmission path is configured in a meander shape that compensates for a signal propagation delay difference due to an electrical length difference between the first or second transmission path, and in a multiple case, the at least one third transmission path is arranged adjacent to each other in the radial direction and is configured in a meander shape that compensates for a signal propagation delay difference due to an electrical length difference between the first or second transmission path or another third transmission path between the second transmission path.

[0112] (Configuration 6) In any one of configurations 1 to 5, 2. A wireless communication device, comprising: a communication transmission path configured to have a differential impedance of 100 Ω; (Configuration 7) In configuration 6, A wireless communication device, wherein each of the transmission lines is configured to have a characteristic impedance of 50 Ω. (Configuration 8) In any one of configurations 1 to 7, A wireless communication device, characterized in that each of the transmission paths has one end connected to the communication means and the other end connected to a termination resistor.

[0113] (Configuration 9) In any one of configurations 1 to 8, the communication transmission line has one or more differential pairs including a differential pair formed of the first and second transmission lines, A wireless communication device characterized in that a first signal input to one of two radially adjacent transmission paths of each of the differential pairs and a second signal input to the other are differential signals having opposite phases. (Configuration 10) In any one of configurations 1 to 8, A wireless communication device, wherein the signals input to each of the transmission paths are different signals input simultaneously in parallel.

[0114] (Configuration 11) In any one of configurations 1 to 10, 2. A wireless communication device, comprising: a communication transmission line formed of a copper pattern on a dielectric substrate; (Configuration 12) In any one of configurations 1 to 11, A wireless communication device, wherein a meander width, which is the amplitude of a meander wiring portion that constitutes the meander shape, is set to 50 to 75% of the width of the transmission path that constitutes the meander shape.

[0115] (Configuration 13) A first wireless communication device that is the wireless communication device according to any one of configurations 1 to 12; a second wireless communication device including: a second communication transmission path having a plurality of transmission paths each facing a transmission path surface of a first communication transmission path, which is the communication transmission path of the first wireless communication device, at a predetermined interval; and a second communication means connected to the plurality of transmission paths and inputting a signal to the plurality of transmission paths or receiving a signal from the plurality of transmission paths; A wireless communication system comprising: (Configuration 14) In configuration 13, a moving means for moving at least one of the first communication transmission path and the second communication transmission path along the other while maintaining the opposing state of the transmission path surfaces, and for rotating the first communication transmission path and the second communication transmission path around a rotation axis; A wireless communication system, characterized in that each of the first communication transmission path and the second communication transmission path is arranged in an arc shape or along an arc centered on the axis of the rotating shaft.

[0116] (Method 1) a communication transmission line including a first transmission line made of a conductor arranged in an arc shape, and a second transmission line arranged radially inside the first transmission line, concentric with the first transmission line, and made of a conductor arranged in a shape along a circular arc that is shorter than the first transmission line; a communication means connected to the first and second transmission paths and communicating with the first and second transmission paths; A control method for controlling a wireless communication device in which the second transmission path is configured in a meander shape to correct a signal propagation delay difference due to an electrical length difference with the first transmission path, A control method comprising a communication step in which the communication means inputs a signal to the first and second transmission paths, or receives a signal from the first and second transmission paths.

[0117] (Method 2) A first wireless communication device according to any one of claims 1 to 11; A control method for controlling a wireless communication system including a second wireless communication device including a second communication transmission path having a plurality of transmission paths each facing a transmission path surface of a first communication transmission path, the first communication transmission path being the communication transmission path of the first wireless communication device, at a predetermined interval, and a second communication means connected to the plurality of transmission paths and communicating with the plurality of transmission paths, a first communication step in which the communication means inputs a signal to each transmission path of the first communication transmission path or receives a signal from each transmission path; a second communication step in which the second communication means inputs signals to the plurality of transmission paths or receives signals from the plurality of transmission paths.

[0118] (Configuration 15) A program for causing a computer to function as each of the means of the wireless communication device described in any one of configurations 1 to 12. (Configuration 16) A program for causing a computer to function as each of the means of the wireless communication system according to configuration 13 or 14. [Explanation of symbols]

[0119] 1 to 5: wireless communication system, 10, 10', 11 to 14, 20 to 22: wireless communication device, 101, 101': communication transmission path, 102, 102': power supply section, 104, 104': termination section, 111, 112, 111', 112', 211, 212: transmission path, 114, 114': termination resistor, 105, 105': differential amplifier circuit, 106: transmission circuit, 200: coupler, 201: waveform shaping circuit, 118, 202, 221: reception circuit

Claims

1. A wireless communication device that performs wireless communication with another wireless communication device by electromagnetic field coupling, a communication transmission line including a first transmission line made of a conductor arranged in an arc shape, and a second transmission line arranged radially inside the first transmission line, concentric with the first transmission line, and made of a conductor arranged in a shape along a circular arc shorter than the first transmission line; a communication means connected to the first and second transmission paths and configured to input a signal to the first and second transmission paths or receive a signal from the first and second transmission paths; A wireless communication device, wherein the second transmission path is configured in a meandering shape to correct a difference in signal propagation delay due to a difference in electrical length with the first transmission path.

2. In claim 1, The wireless communication device, wherein the second transmission path is arranged along a circular arc that is concentric with the first transmission path and has the same central angle as the first transmission path.

3. In claim 1, A wireless communication device characterized in that the second transmission path is configured in a meandering shape so that the phase difference of the signal caused by the difference between the electrical length from one end to the other end of the first transmission path and the electrical length from one end to the other end of the second transmission path is 90° or less in order to correct the propagation delay difference.

4. In claim 1, A plurality of the communication transmission paths are provided, A wireless communication device characterized in that the multiple communication transmission paths are each arranged at a predetermined interval in the circumferential direction, and each two of the communication transmission paths adjacent to each other in the circumferential direction are arranged such that one end of the first and second transmission paths of one of the paths and the other end of the first and second transmission paths of the other path, or one end or the other end of the first and second transmission paths of both paths are arranged closely adjacent to and facing each other in the circumferential direction.

5. In claim 1, the communication transmission line has at least one third transmission line made of a conductor arranged radially inside the second transmission line, concentric with the second transmission line, and shaped along a circular arc shorter than the second transmission line; A wireless communication device characterized in that, in one case, the at least one third transmission path is configured in a meander shape that compensates for a signal propagation delay difference due to an electrical length difference between the first or second transmission path, and in a multiple case, the at least one third transmission path is arranged adjacent to each other in the radial direction and is configured in a meander shape that compensates for a signal propagation delay difference due to an electrical length difference between the first or second transmission path or another third transmission path between the second transmission path.

6. In claim 1, A wireless communication device, wherein the communication transmission path is configured to have a differential impedance of 100Ω.

7. In claim 6, A wireless communication device, wherein the first and second transmission paths are each configured to have a characteristic impedance of 50 Ω.

8. In claim 1, A wireless communication device, wherein the communication means is connected to one ends of the first and second transmission paths, and a termination resistor is connected to the other ends.

9. In claim 1, A wireless communication device, characterized in that a first signal input to the first transmission path and a second signal input to the second transmission path are differential signals having opposite phases.

10. In claim 1, A wireless communication device, characterized in that a first signal input to the first transmission path and a second signal input to the second transmission path are different signals input simultaneously in parallel.

11. In claim 1, 2. A wireless communication device, comprising: a first communication transmission line formed of a copper pattern on a dielectric substrate;

12. In claim 1, A wireless communication device, wherein a meander width, which is the amplitude of a meander wiring portion that constitutes the meander shape, is set to 50 to 75% of the width of the second transmission line.

13. A first wireless communication device, which is a wireless communication device according to any one of claims 1 to 12; a second wireless communication device including: a second communication transmission path having a plurality of transmission paths each facing a transmission path surface of a first communication transmission path, the communication transmission path being the communication transmission path of the first wireless communication device, at a predetermined interval; and a second communication means connected to the plurality of transmission paths and inputting a signal to the plurality of transmission paths or receiving a signal from the plurality of transmission paths; A wireless communication system comprising:

14. In claim 13, a moving means for moving at least one of the first communication transmission path and the second communication transmission path along the other while maintaining the opposing state of the transmission path surfaces, and for rotating the first communication transmission path and the second communication transmission path around a rotation axis; A wireless communication system, characterized in that each of the first communication transmission path and the second communication transmission path is arranged in an arc shape or along an arc centered on the axis of the rotating shaft.

15. a communication transmission line including a first transmission line made of a conductor arranged in an arc shape, and a second transmission line arranged radially inside the first transmission line, concentric with the first transmission line, and made of a conductor arranged in a shape along a circular arc shorter than the first transmission line; a communication means connected to the first and second transmission paths and configured to communicate with the first and second transmission paths; A control method for controlling a wireless communication device in which the second transmission path is configured in a meander shape to correct a signal propagation delay difference due to an electrical length difference with the first transmission path, A control method comprising a communication step in which the communication means inputs a signal to the first and second transmission paths, or receives a signal from the first and second transmission paths.

16. A first wireless communication device, which is a wireless communication device according to any one of claims 1 to 11; A control method for controlling a wireless communication system including: a second wireless communication device including a second communication transmission path having a plurality of transmission paths each facing a transmission path surface of a first communication transmission path, the first communication transmission path being the communication transmission path of the first wireless communication device, at a predetermined interval; and a second communication means connected to the plurality of transmission paths and communicating with the plurality of transmission paths, a first communication step in which the communication means inputs a signal to each transmission path of the first communication transmission path or receives a signal from each transmission path; a second communication step in which the second communication means inputs signals to the plurality of transmission paths or receives signals from the plurality of transmission paths.

17. A program for causing a computer to function as each of the means of the wireless communication device according to any one of claims 1 to 12.

18. A program for causing a computer to function as each of the means of the wireless communication system according to claim 13.

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