Transmission device and transmission system

Abstract

To provide a transmission device that can reduce the effects of manufacturing errors in transmission lines, ensure communication quality, and achieve high-speed communication.SOLUTION: A transmission device 10 includes a conductor part 110, a substrate disposed above the conductor part 110, and support members 121, 122 disposed on the conductor part 110 and supporting the substrate 100. The substrate 100 includes first electrode 101 and second electrode 102 forming a differential transmission line and a third electrode 103 disposed between the first electrode 101 and the second electrode 102. The conductor part 110 and the third electrode 103 function as a reference potential of the differential transmission line.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a transmission device and a transmission system. [Background technology]

[0002] In recent years, close-proximity wireless communication systems that use electromagnetic coupling to perform wireless communication between nearby devices have been proposed, and there is an increasing demand for large-volume communication such as image data and high-speed communication. As a transmission device used in such close-proximity wireless communication systems, a structure has been proposed in Patent Document 1 that reduces transmission loss by providing a space between a substrate on which a transmission line is mounted and a portion that forms a reference potential. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2001-230606 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a wireless communication system using electromagnetic coupling, the efficiency of communication can be improved by using a transmission line with low transmission loss as in Patent Document 1. However, in a structure in which a transmission line is implemented as in Patent Document 1, in addition to manufacturing a substrate, a process of manufacturing a metal plate that forms a reference potential and combining them is required, so ensuring manufacturing precision is an issue. If the implementation is performed using a manufacturing method that is low cost and has low precision, there is a problem that the characteristic impedance deviates from the target value, resulting in deterioration of communication quality. In addition, when the transmission line is a differential transmission line, symmetry of the two transmission lines is required, but if the symmetrical nature is lost due to manufacturing errors, the characteristic impedances of the two transmission lines will differ, further deteriorating communication quality.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and has an object to provide a transmission device that reduces the influence of manufacturing errors in the transmission device, ensures communication quality, and enables high-speed communication. [Means for solving the problem]

[0006] The transmission device disclosed herein comprises a conductor portion and a substrate arranged above the conductor portion, the substrate having a first electrode and a second electrode that form a transmission line, and a third electrode arranged between the first electrode and the second electrode, and the conductor portion and the third electrode operate as a reference potential for the transmission line. Effect of the Invention

[0007] According to the present disclosure, a transmission device is realized that reduces the influence of manufacturing errors in the transmission device, ensures communication quality, and enables high-speed communication. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic diagram showing a schematic configuration of a transmission device according to a first embodiment. [Diagram 2] FIG. 1 is a schematic diagram showing a schematic configuration of a transmission device according to a comparative example. [Diagram 3] FIG. 11 is a characteristic diagram of a transmission device, with the horizontal axis representing the ratio of the distance between the first and second electrodes and the third electrode to the width of the first and second electrodes, and the vertical axis representing the rate of change in differential impedance when the height of the support member is changed. [Figure 4] FIG. 11 is a schematic diagram showing a schematic configuration of a transmission device according to a second embodiment. [Diagram 5] 13 is a schematic diagram illustrating a case in which a manufacturing error occurs and a connection position of a substrate and a support member is misaligned in the transmission device of the second embodiment. FIG. [Figure 6] 13A and 13B are schematic diagrams illustrating a case in which a manufacturing error occurs and the width of a support member changes in the transmission device according to the second embodiment. [Figure 7] FIG. 13 is a schematic diagram showing a schematic configuration of a first example of a transmission system according to a third embodiment. [Figure 8]FIG. 11 is a perspective view showing a schematic configuration of a second example of a transmission system according to the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, preferred embodiments to which the present invention can be applied will be described in detail with reference to the drawings. In the following description, components common to multiple drawings are given common reference numerals. Therefore, the common components will be described with mutual reference to multiple drawings, and the description of the components given common reference numerals will be omitted as appropriate.

[0010] -First embodiment- [Transmission device configuration] First, a transmission device according to a first embodiment will be described. FIG. 1 is a schematic diagram showing a schematic configuration of a transmission device according to this embodiment, where (a) is a perspective view and (b) is a cross-sectional view of a transmission line seen from the extension direction.

[0011] The transmission device 10 of this embodiment has a conductor portion 110 and a substrate 100 disposed above the conductor portion 110. The conductor section 110 is, for example, a metal plate made of a highly conductive metal material such as aluminum, etc. The conductor section 110 is a so-called ground plane, and is set to a reference potential of the differential transmission line, which will be described later.

[0012] The substrate 100 is, for example, a flexible printed circuit board. On the substrate 100, a first electrode 101 and a second electrode 102 extending in parallel are formed as a so-called microstrip line. The first electrode 101 and the second electrode 102 have substantially the same thickness and width. The first electrode 101 and the second electrode 102 form a transmission line, here a differential transmission line. One end of the differential transmission line formed by the first electrode 101 and the second electrode 102 is connected to a differential transmission buffer 130, which is connected to a signal source 131. An electric signal output from the signal source 131 is input to the differential transmission line 102 as a differential signal via the differential transmission buffer 131 connected to one end (input section) of the differential transmission line. The other end of the first electrode 101 and the second electrode 102 forming the differential transmission line is terminated by a termination resistor 132 having substantially the same characteristic impedance.

[0013] In this embodiment, the substrate 100 is provided with a third electrode 103 between the first electrode 101 and the second electrode 102, extending in parallel with the first electrode 101 and the second electrode 102 at a predetermined interval, and serving as a reference potential of the differential transmission line. The third electrode 103 has a thickness substantially equal to that of the first electrode 101 and the second electrode 102, and a width narrower than that of the first electrode 101 and the second electrode 102. In the substrate 100, the first electrode 101, the second electrode 102, and the third electrode 103 are located on a virtual flat surface at a constant distance from the upper surface of the conductor section 110 of the substrate 100, and are substantially equal in height from the upper surface of the conductor section 110. This configuration maintains strong electromagnetic coupling between the first electrode 101 and the third electrode 103, and between the second electrode 102 and the third electrode 103. The third electrode 103 and the conductor portion 110 are electrically connected to each other at the ends of the differential transmission lines in the extension direction, and are at the same potential, and act as a reference potential for the differential transmission lines. With this configuration, even if a design error occurs during the manufacture of the transmission device 10, the fluctuation in the characteristic impedance can be suppressed to a small value.

[0014] Support members 121 and 122 for supporting the substrate 100 are disposed on the conductor portion 110. The support members 121 and 122 are made of an insulator, for example, an insulating material having a relative dielectric constant similar to that of air, and extend in parallel with the first electrode 101 and the second electrode 102 constituting the differential transmission line. By providing the support members 121 and 122, a gap 120 is formed between the conductor portion 110 and the substrate 100. The gap 120 is filled with, for example, air. Instead of filling the gap 120 with air, it is also possible to fill the gap 120 with, for example, an insulating material having a dielectric constant close to that of air, taking into account the strength of the transmission device 10, etc.

[0015] In this embodiment, the first electrode 101 and the third electrode 103, and the second electrode 102 and the third electrode 103 are electromagnetically coupled stronger than the first electrode 101 and the conductor 110 and the support member 121, and the second electrode 102 and the conductor 110 and the support member 121. The degree of electromagnetic coupling can be known by, for example, measuring a coupling coefficient.

[0016] [Actions and Effects of the Transmission Device According to the Present Embodiment] The following describes the actions and effects of the transmission device according to the present embodiment shown in FIG. 1, based on a comparison with a comparative example.

[0017] FIG. 2 is a schematic diagram showing a schematic configuration of a transmission device according to a comparative example, where (a) is a perspective view and (b) is a cross-sectional view of a transmission line as viewed from the extension direction. The transmission device 20 of the comparative example does not have the third electrode 103 of the transmission device 10 of the present embodiment. In this transmission device 20, the reference potential of the differential transmission line exists only in the conductor portion 110. Therefore, in the transmission device 20, manufacturing errors occur in the conductor portion 110 and the support members 121 and 122 during manufacturing, and when the positional relationship between the conductor portion 110 and the substrate 100 changes, the characteristic impedance changes.

[0018] 1, in the transmission device 10 of the present embodiment, the third electrode 103, which has stronger electromagnetic coupling with the first electrode 101 and the second electrode 102 than the conductor 110, exists on the substrate 100 as a reference potential. Therefore, even if manufacturing errors occur in the conductor 110 and the support members 121 and 122 during manufacturing, it is possible to reduce the effect on the characteristic impedance.

[0019] Next, the operation and effect of the transmission device 10 will be described based on the results of analysis using a simulation.

[0020] In the simulation, the substrate 100 was a flexible printed circuit board. The gap 120 was filled with air. The conductor 110 and the electrode 103 were connected at the end of the transmission line in the extension direction and were at the same potential. The support members 121 and 122 were members whose relative dielectric constant was approximately equal to that of air.

[0021] 1 was analyzed using the design parameters shown in Table 1. As a result, the characteristic impedance of the differential transmission line was 88Ω for differential impedance and 45Ω for single-end impedance.

[0022] [Table 1]

[0023] Similarly, the configuration of the transmission device 20 of the comparative example shown in Fig. 2 was analyzed using the design parameters shown in the following Table 2. As a result, the characteristic impedance of the differential transmission line was 97Ω for the differential impedance and 65Ω for the single-end impedance.

[0024] [Table 2]

[0025] A simulation was used to analyze the case where the height of the support members 121, 122 changes due to manufacturing errors when the transmission device 10 according to the present embodiment in Fig. 1 and the transmission device 20 according to the comparative example in Fig. 2 are designed with the parameters in Tables 1 and 2. Here, a simulation was performed to analyze the effect on the characteristic impedance when the height of the support members 121, 122 increases and the electrodes 101, 102 and the conductor portion 110 deviate from the design values.

[0026] The case of the transmission device 10 according to the present embodiment shown in Fig. 1 will be described. When the height of the support members 121, 122 is increased from 3 mm to 3.5 mm, the differential impedance is 90Ω, and the single-end impedance is 46Ω, which means that the differential impedance and the single-end impedance have changed by about 2% and about 2%. When the height of the support members 121, 122 is increased from 3 mm to 4 mm, the differential impedance is 93Ω, and the single-end impedance is 47Ω, which means that the differential impedance and the single-end impedance have changed by about 5% and about 4%.

[0027] The case of the transmission device 20 according to the comparative example of Fig. 2 will be described. When the height of the support members 121, 122 is increased from 3 mm to 3.5 mm, the differential impedance is 101 Ω, the single-end impedance is 70 Ω, and the differential impedance has changed by about 4%, and the single-end impedance has changed by about 7%. When the height of the support members 121, 122 is increased from 3 mm to 4 mm, the differential impedance is 105 Ω, the single-end impedance is 72 Ω, and the differential impedance has changed by about 8%, and the single-end impedance has changed by about 10%.

[0028] In the above example, the heights of the support members 121 and 122 were changed when there was no electrode serving as a reference potential between the differential transmission lines as in the comparative example of Fig. 2. In this case, it was confirmed that the change in the distance between the substrate 100 and the conductor portion 110 caused the distance between the reference potential and the differential transmission lines to fluctuate, resulting in a large change in characteristic impedance.

[0029] 1, when the third electrode 103 serving as the reference potential is present between the differential transmission lines, the heights of the support members 121, 122 are changed. In this case, even if the distance between the substrate 100 and the conductor 110 changes and the distance between the conductor 110 serving as the reference potential and the differential transmission lines fluctuates, the presence of the electrode 103 serving as the reference potential makes it difficult for the characteristic impedance to change.

[0030] As described above, by using the transmission device 10 according to this embodiment, even if manufacturing errors occur in the height of the support members 121, 122, the effect on the characteristic impedance can be reduced, and the quality of the transmission signal can be maintained.

[0031] In the above simulation experiment, the heights of the support members 121 and 122 are set to be sufficiently larger than the distance between the first electrode 101 and the second electrode 102 and the third electrode 103. To obtain a particularly significant effect of reducing the influence on the characteristic impedance of the manufacturing error in the heights of the support members 121 and 122, it is necessary that the electrode 103 be electromagnetically coupled more strongly with the electrodes 101 and 102 than with the conductor portion 110 as the reference potential of the differential transmission line.

[0032] FIG. 3 is a characteristic diagram of transmission device 10, with the horizontal axis representing the ratio of the distance between electrodes 101, 102 and third electrode 103 to the width of electrodes 101, 102, and the vertical axis representing the rate of change in differential impedance when the height of support members 121, 122 is changed from 3 mm to 3.5 mm. 3, in order to suppress the rate of change in differential impedance to, for example, 5% or less with respect to changes in support members 121, 122, the ratio of the distance between electrodes 101, 102 and third electrode 103 to the width of electrodes 101, 102 must be 0.12 or less. In this way, in order to reduce the effect on the characteristic impedance even if manufacturing errors occur in support members 121, 122 and the height changes, it is sufficient to design electrodes 101, 102 and electrode 103 to be closer to each other.

[0033] In this embodiment, as shown in Fig. 1, the case where the support members 121, 122 are present between the conductor 110 and the substrate 100 over the entire length of the differential transmission line is illustrated, but the present invention is not limited to this. For example, the support members may be arranged only at a predetermined part in the extension direction of the differential transmission line, or a plurality of support members may be arranged in the extension direction of the differential transmission line.

[0034] As described above, according to this embodiment, a transmission device is realized that reduces the influence of manufacturing errors in the transmission device, ensures communication quality, and enables high-speed communication.

[0035] -Second embodiment- [Transmission device configuration] Next, a transmission device according to a second embodiment will be described. FIG. 4 is a schematic diagram showing a schematic configuration of a transmission device according to this embodiment, where (a) is a perspective view and (b) is a cross-sectional view of a transmission line seen from the extension direction.

[0036] The transmission device 40 of this embodiment has a conductor portion 110 similar to that of the transmission device 10, and a substrate 400 disposed above the conductor portion 110. The substrate 400, like the substrate 100 of the transmission device 10, has a first electrode 101 and a second electrode 102 that constitute a differential transmission line, and a third electrode 103 that is formed between the first electrode 101 and the second electrode 102 and serves as a reference potential for the differential transmission line.

[0037] In this embodiment, the substrate 400 has, in addition to the first electrode 101, the second electrode 102, and the third electrode 103, a fourth electrode 404 and a fifth electrode 405 that extend in parallel with these electrodes at a predetermined interval and are set as the reference potential of the differential transmission line. The fourth electrode 404 is formed at a position adjacent to the first electrode 101 on the opposite side to the third electrode 103. The fifth electrode 405 is formed at a position adjacent to the second electrode 102 on the opposite side to the third electrode 103. The fourth electrode 404 and the fifth electrode 405 have approximately the same thickness and approximately the same width. In the substrate 400, the first electrode 101, the second electrode 102, the third electrode 103, the fourth electrode 404, and the fifth electrode 405 are located on a virtual flat surface at a constant distance from the upper surface of the conductor section 110 of the substrate 400, and are approximately the same height from the upper surface of the conductor section 110. With this configuration, strong electromagnetic coupling is maintained between the first electrode 101 and the third electrode 103, between the second electrode 102 and the third electrode 103, between the first electrode 101 and the fourth electrode 404, and between the second electrode 102 and the fifth electrode 405. The third electrode 103, the fourth electrode 404, and the fifth electrode 405 are electrically connected to the conductor portion 110 at the end of the extension direction of the differential transmission line, and are at the same potential, which is the reference potential of the differential transmission line here. With this configuration, even if a design error occurs in the differential transmission line, etc., it is possible to suppress the variation in the characteristic impedance to a small value.

[0038] As in the case of the transmission device 10, support members 121, 122 that support the substrate 100 are disposed on the conductor 110, and a gap 120 filled with air is formed between the conductor 110 and the substrate 100. The support members 121, 122 are made of a conductor, for example, aluminum, which is a metal material with excellent conductivity. Note that, although the conductor 110 and the support members 121, 122 are configured as separate bodies in this embodiment, it is also possible to form the conductor 110 and the support members 121, 122 integrally from the same conductive material.

[0039] In this embodiment, the fourth electrode 404 is arranged in alignment with the contact portion of the support member 121 with the substrate 400, and the fifth electrode 405 is arranged in alignment with the contact portion of the support member 123 with the substrate 400. Specifically, the center position of the fourth electrode approximately coincides with the center position of the support member 121 at the contact portion, and the center position of the fifth electrode approximately coincides with the center position of the support member 122 at the contact portion. In this way, by arranging the electrodes 404, 405 in alignment with the contact portions of the support members 121, 122 with the substrate 400, even if manufacturing errors occur in these positions and cause slight deviations, the variation in characteristic impedance can be suppressed as small as possible.

[0040] Furthermore, the width of fourth electrode 404 is greater than the width of supporting member 121 at the contact portion, and the width of fifth electrode 405 is greater than the width of supporting member 121 at the contact portion. By adopting this configuration, even if a manufacturing error occurs and supporting members 121, 122 come close to electrodes 101, 102, the fluctuation in characteristic impedance can be kept as small as possible.

[0041] As in the case of the transmission device 10, the first electrode 101 and the third electrode 103, and the second electrode 102 and the third electrode 103 are electromagnetically coupled stronger than the first electrode 101 and the conductor 110 and the support member 121, and the second electrode 102 and the conductor 110 and the support member 121. Furthermore, in this embodiment, the first electrode 101 and the fourth electrode 404, and the second electrode 102 and the fifth electrode 405 are electromagnetically coupled stronger than the first electrode 101 and the conductor 110 and the support member 121, and the second electrode 102 and the conductor 110 and the support member 121.

[0042] [Actions and Effects of the Transmission Device According to the Present Embodiment] The actions and effects of the transmission device according to the present embodiment shown in FIG. 4 will be described below based on a comparison with a comparative example.

[0043] 4, in the transmission device 40 of the present embodiment, a third electrode 103, a fourth electrode 404, and a fifth electrode 405, which are electromagnetically coupled to the first electrode 101 and the second electrode 102 stronger than the conductor 110 and the support members 121 and 122, are present on the substrate 400 as a reference potential. Therefore, even if manufacturing errors occur in the conductor 110 and the support members 121 and 122 during manufacturing, it is possible to reduce the effect on the characteristic impedance.

[0044] Hereinafter, the operation and effect of the transmission device 40 will be described based on the results of analysis using a simulation. In the following simulation, the support members 121 and 122 are members formed of the same metal as the conductor portion 110.

[0045] First, the characteristic impedance of the differential transmission line was analyzed by simulation. In addition to the parameters (Table 1) used in the simulation of the transmission device 10 of the first embodiment described above, the width of the fourth electrode 404 and the fifth electrode 405 was set to 2 mm. When the characteristic impedance of the differential transmission line was simulated, the differential impedance was 102Ω and the single-end impedance was 54Ω.

[0046] 2, when there is no electrode serving as a reference potential between the differential transmission lines, the support members 121 and 122 are made of the same metal as the conductor portion 110, and analysis was performed by simulation using the design parameters shown in Table 2. The result was a differential impedance of 97Ω and a single-ended impedance of 64Ω.

[0047] Next, an analysis was performed by simulation regarding the effect on the characteristic impedance of the differential transmission line when a manufacturing error occurs and the connection position of the substrate and the support member is misaligned.

[0048] 5 is a schematic diagram showing a case where a manufacturing error occurs in the transmission device 40 of this embodiment and the connection positions of the substrate 400 and the support members 121 and 122 are misaligned. Here, with the same parameters as above, the amount of misalignment d from the center position of the fourth electrode 404 (fifth electrode 405) and the support member 121 (122) is set to 0.5 mm. At this time, in the transmission device 40 according to this embodiment of FIG. 5, the differential impedance has changed to 101Ω, the single-end impedance of the first electrode 101 has changed to 55Ω, and the single-end impedance of the second electrode 102 has changed to 53Ω.

[0049] In the case where there is no electrode serving as a reference potential between the differential transmission lines as in the comparative example of Fig. 2, a simulation was performed for the case where the connection positions of the substrate 400 and the support members 121 and 122 are shifted by 0.5 mm as in Fig. 5. As a result, the differential impedance changed to 96 Ω, the single-end impedance of electrode 101 changed to 66 Ω, and the single-end impedance of electrode 102 changed to 61 Ω.

[0050] When there is no electrode serving as a reference potential on the substrate 100 as in the comparative example, the single-end impedance varies by about ±5% from the design value, widening the impedance difference between the first electrode 101 and the second electrode 102. In contrast, when there are electrodes 103, 404, and 405 serving as a reference potential on the substrate 400 as in this embodiment, it was confirmed that the single-end impedance varies only by about ±2% from the design value, and almost no impedance difference occurs between the two electrodes.

[0051] As described above, it has been found that use of the transmission device 40 according to this embodiment has the effect of reducing the influence of connection errors between the substrate 400 and the support members 121 and 122 on the characteristic impedance of the differential transmission lines.

[0052] Next, an analysis was performed by simulation regarding the effect on the characteristic impedance when a manufacturing error occurs in the support members 121 and 122 and the width is changed.

[0053] FIG. 6 is a schematic diagram showing a case where the width of the support members 121, 122 has changed due to a manufacturing error in the transmission device 40 of this embodiment, where (b) shows a case where there is no manufacturing error, (a) shows a case where the width is slightly narrower, and (c) shows a case where the width is slightly wider. Here, only the width of the support members 121, 122 was changed by ±0.5 mm, and a simulation was performed with the same parameters as above. In this case, in the transmission device 40 according to this embodiment of FIG. 4, when the width of the support members 121, 122 became 0.5 mm, the differential impedance changed to 101 Ω and the single-end impedance changed to 54 Ω. Also, when the width of the support members 121, 122 became 1.5 mm, the differential impedance changed to 103 Ω and the single-end impedance changed to 55 Ω.

[0054] A simulation was performed in which only the width of the support members 121, 122 was changed by ±0.5 mm in the case where there was no electrode serving as a reference potential between the differential transmission lines as in the comparative example of Fig. 2. As a result, when the width of the support members 121, 122 was 0.5 mm, the differential impedance changed to 101 Ω and the single-end impedance changed to 67 Ω. Also, when the width of the support members 121, 122 was 1.5 mm, the differential impedance changed to 94 Ω and the single-end impedance changed to 61 Ω.

[0055] When there is no electrode serving as a reference potential on the substrate 100 as in the comparative example, the differential impedance changes by approximately ±4%. In contrast, when there are electrodes 103, 404, and 405 serving as a reference potential on the substrate 400 as in this embodiment, the differential impedance changes by only ±1%. Furthermore, when there is no electrode serving as a reference potential on the substrate 100 as in the comparative example, the single-end impedance changes by approximately ±5%. In contrast, when there are electrodes 103, 404, and 405 serving as a reference potential on the substrate 400 as in this embodiment, the single-end impedance changes by only ±2%.

[0056] As described above, it has been found that the use of the transmission device 40 according to this embodiment has the effect of reducing the influence of manufacturing errors of the support members 121 and 122 on the characteristic impedance.

[0057] The effect of reducing the influence of the characteristic impedance on the manufacturing error of the support members 121, 122 as described above is more remarkable when the width of the fourth electrode 404 and the fifth electrode 405 is larger than the width of the support members 121, 122. For the transmission device 400 according to the present embodiment, the width of the support members 121, 122 was set to 1 mm, and the width of the fourth electrode 404 and the fifth electrode 405, which serve as the reference potential, was changed, and the influence of the characteristic impedance when a manufacturing error occurs was analyzed by simulation.

[0058] When the width of the fourth electrode 404 and the fifth electrode 405 was set to 1 mm, and the width of the support members 121, 122 was also set to the same 1 mm as these electrodes, the differential impedance was 97 Ω and the single-end impedance was 52 Ω. In contrast, when the width of the support members 121, 122 was 1.5 mm, the differential impedance decreased to 92 Ω and the single-end impedance decreased to 49 Ω.

[0059] In this way, it was confirmed that the variation in the characteristic impedance when a manufacturing error occurs can be suppressed to a small value by forming the electrodes 404, 405 wider than the support members 121, 122. If the width of the electrodes 404, 405 is equal to or smaller than the width of the support members 121, 122, the effect of the characteristic impedance when a manufacturing error occurs is large because the support members 121, 122 approach the electrodes 101, 102 due to the manufacturing error, and the electromagnetic coupling becomes stronger. By making the width of the electrodes 404, 405 larger than the width of the support members 121, 122, the electromagnetic coupling between the electrodes 101, 102 and the electrodes 404, 405 is maintained strong. Therefore, even if a manufacturing error occurs and the support members 121, 122 approach the electrodes 101, 102, the variation in the characteristic impedance can be suppressed to a small value, which is preferable.

[0060] As described above, according to this embodiment, a transmission device is realized that reduces the influence of manufacturing errors in the transmission device, ensures communication quality, and enables high-speed communication.

[0061] -Third embodiment- Next, a transmission system according to a third embodiment will be described. The wireless communication system, which is the transmission system of this embodiment, has a signal transmitting unit that transmits a wireless signal, and a signal receiving unit that receives the wireless signal transmitted from the signal transmitting unit.

[0062] [Example 1 of a transmission system] FIG. 7 is a schematic diagram showing a first example of the schematic configuration of a transmission system according to this embodiment, where (a) is a perspective view and (b) is a cross-sectional view of a transmission line as seen from the extension direction. 7(a), in the first example of the wireless communication system, the signal transmitting unit is a transmission device constituting a transmission line on the transmitting side, and in this case is the transmission device 40 according to the second embodiment described above. Note that, instead of the transmission device 40, the transmission device 10 according to the first embodiment can also be applied.

[0063] The signal receiving section is a transmission line 700 on the receiving side. The transmission line 700 has electrodes 701 and 702 and a receiving circuit 703. The transmission line 700 is electromagnetically coupled to the transmission device 40 in a non-contact state while maintaining a certain distance from the transmission device 40, and performs wireless communication. The electrode 701 of the transmission line 700 faces the first electrode 101 of the transmission device 40, and the electrode 702 faces the second electrode 102 of the transmission device 40. The transmission line 700 moves along the extension direction of the differential transmission line in the transmission device 40, and receives a wireless signal from the transmission line on the transmitting side. The wireless signal received by the transmission line 700 is detected as a received signal by the receiving circuit 703. The input impedance of the signal source 130 of the transmission device 40 is approximately equal to the differential impedance of the transmission line.

[0064] Here, a case will be considered in which a transmission device that does not have an electrode serving as a reference potential on the substrate is used in place of the transmission device 40 in a wireless communication system. In this case, if the differential impedance changes due to manufacturing errors in a transmission device that does not have an electrode serving as a reference potential, the impedance at the connection point between the signal source 130 and the differential transmission line becomes mismatched, and the transmitted signal becomes small. As a result, the signal detected by the receiving circuit 703 of the transmission line 700 becomes small, making it difficult to perform high-speed communication. In contrast, in this embodiment, by using the transmission device 40 that has an electrode serving as a reference potential on the substrate, the differential impedance is unlikely to change due to manufacturing errors in the transmission device 40, making it possible to easily perform high-speed communication and maintain excellent communication quality.

[0065] [Second example of a transmission system] FIG. 8 is a perspective view showing a second example of the schematic configuration of the transmission system according to the present embodiment. In the second example of the wireless communication system, a transmission device 70, which is a signal transmitting unit, has a different input method of a differential signal from the transmission device 40 of the first example described above. In the transmission device 70, independent signal sources 711, 712 and transmission buffers 713, 714 are connected to the first electrode 101 and the second electrode 102, respectively, and are driven in a single mode. The input impedance of the signal sources 711, 712 is approximately equal to the single-ended impedance of the differential transmission line.

[0066] Here, a case will be considered in which a transmission device that does not have an electrode serving as a reference potential on the substrate is used in place of the transmission device 70 in a wireless communication system. In this case, if the differential impedance changes due to manufacturing errors in a transmission device that does not have an electrode serving as a reference potential, the impedance at the connection point between the signal source 130 and the differential transmission line becomes mismatched, and the transmitted signal becomes small. As a result, the signal detected by the receiving circuit 703 of the transmission line 700 becomes small, making it difficult to perform high-speed communication. In contrast, in this embodiment, by using the transmission device 40 that has an electrode serving as a reference potential on the substrate, the differential impedance is unlikely to change due to manufacturing errors in the transmission device 70, making it possible to easily perform high-speed communication and maintain excellent communication quality.

[0067] The disclosure of various embodiments includes the following configurations. (Configuration 1) A conductor portion; A substrate disposed above the conductor portion; It is equipped with The substrate is A first electrode and a second electrode serving as a transmission line; a third electrode disposed between the first electrode and the second electrode; It has The conductor portion and the third electrode act as a reference potential of the transmission line. A transmission device comprising: (Configuration 2) the first electrode and the third electrode, and the second electrode and the third electrode are electromagnetically coupled stronger than the first electrode and the conductor portion, and the second electrode and the conductor portion; 2. The transmission device according to claim 1. (Configuration 3) the first electrode, the second electrode, and the third electrode are located on a virtual flat surface of the substrate; 3. The transmission device according to configuration 1 or 2. (Configuration 4) A support member for supporting the substrate is disposed on the conductor portion. The transmission device according to any one of configurations 1 to 3. (Configuration 5) The support member forms a gap between the conductor portion and the substrate. 5. The transmission device according to claim 4. (Configuration 6) The void is filled with air. 6. The transmission device according to configuration 5. (Configuration 7) The third electrode and the conductor portion are electrically connected to each other at an end portion in an extension direction of the transmission line and have the same potential. The transmission device according to any one of configurations 1 to 6. (Configuration 8) The substrate is a fourth electrode adjacent to the first electrode on the opposite side to the third electrode; a fifth electrode adjacent to the second electrode on the opposite side to the third electrode; It has the fourth electrode and the fifth electrode act as the reference potential of the transmission line; The transmission device according to any one of configurations 1 to 7. (Configuration 9) the first electrode, the second electrode, the third electrode, the fourth electrode, and the fifth electrode are located on a virtual flat surface of the substrate; The transmission device according to configuration 8. (Configuration 10) A support member for supporting the substrate is disposed on the conductor portion. The transmission device according to configuration 8 or 9. (Configuration 11) The support member forms a gap between the conductor portion and the substrate. 11. The transmission device according to configuration 10. (Configuration 12) The support member is a conductor. 12. A transmission device according to configuration 10 or 11. (Configuration 13) the fourth electrode and the fifth electrode are arranged in alignment with the contact portions of the support member and the substrate; 13. The transmission device according to any one of configurations 10 to 12. (Configuration 14) a central position of the fourth electrode and a central position of the fifth electrode each coincide with a central position of the support member at the contact portion; A transmission device according to configuration 13. (Configuration 15) The width of the fourth electrode and the width of the fifth electrode are each larger than the width of the support member at the contact portion. 15. The transmission device according to configuration 13 or 14. (Configuration 16) the third electrode, the fourth electrode, and the fifth electrode are electrically connected to the conductor portion at an end portion in an extension direction of the transmission line, and are at the same potential. 16. The transmission device according to any one of configurations 8 to 15. (Configuration 17) The transmission line is a differential transmission line. 17. The transmission device according to any one of configurations 1 to 16. (Configuration 18) The substrate is a flexible printed circuit board. The transmission device according to any one of configurations 1 to 17. (Configuration 19) A signal transmitting unit which is a transmission device according to any one of configurations 1 to 18; a signal receiving unit that moves in a direction in which the transmission line extends without contacting the transmission line of the signal transmitting unit; It is equipped with wireless communication is performed by electromagnetic coupling between the signal transmitting unit and the signal receiving unit; Transmission system. [Explanation of symbols]

[0068] 10,20,40,70 Transmission equipment 100,400,700 board 101 1st electrode 102 2nd electrode 103 3rd electrode 110 Conductor 120 void 121,122 Support member 130 Signal source 131 Send Buffer 132 Terminal Resistance 404 4th electrode 405 5th electrode

Claims

1. A conductor portion; A substrate disposed above the conductor portion; It is equipped with The substrate is A first electrode and a second electrode serving as a transmission line; a third electrode disposed between the first electrode and the second electrode; It has The conductor portion and the third electrode act as a reference potential of the transmission line. A transmission device comprising:

2. the first electrode and the third electrode, and the second electrode and the third electrode are electromagnetically coupled stronger than the first electrode and the conductor portion, and the second electrode and the conductor portion; 2. The transmission device according to claim 1.

3. the first electrode, the second electrode, and the third electrode are located on a virtual flat surface of the substrate; 2. The transmission device according to claim 1.

4. A support member for supporting the substrate is disposed on the conductor portion.

2. The transmission device according to claim 1.

5. The support member forms a gap between the conductor portion and the substrate.

5. The transmission device according to claim 4.

6. The void is filled with air.

6. The transmission device according to claim 5.

7. The third electrode and the conductor portion are electrically connected to each other at an end portion in an extension direction of the transmission line and have the same potential.

2. The transmission device according to claim 1.

8. The substrate is a fourth electrode adjacent to the first electrode on the opposite side to the third electrode; a fifth electrode adjacent to the second electrode on the opposite side to the third electrode; It has the fourth electrode and the fifth electrode act as the reference potential of the transmission line; 2. The transmission device according to claim 1.

9. the first electrode, the second electrode, the third electrode, the fourth electrode, and the fifth electrode are located on a virtual flat surface of the substrate; 9. The transmission device according to claim 8.

10. A support member for supporting the substrate is disposed on the conductor portion.

9. The transmission device according to claim 8.

11. The support member forms a gap between the conductor portion and the substrate. The transmission device according to claim 10.

12. The support member is a conductor. The transmission device according to claim 10.

13. the fourth electrode and the fifth electrode are arranged in alignment with the contact portions of the support member and the substrate; The transmission device according to claim 10.

14. a center position of the fourth electrode and a center position of the fifth electrode each coincide with a center position of the support member at the contact portion; A transmission device according to claim 13.

15. a width of the fourth electrode and a width of the fifth electrode are each greater than a width of the support member at the contact portion; A transmission device according to claim 13.

16. the third electrode, the fourth electrode, and the fifth electrode are electrically connected to the conductor portion at an end portion in an extension direction of the transmission line, and are at the same potential; 9. The transmission device according to claim 8.

17. The transmission line is a differential transmission line.

2. The transmission device according to claim 1.

18. The substrate is a flexible printed circuit board.

2. The transmission device according to claim 1.

19. A signal transmitting unit which is a transmission device according to any one of claims 1 to 18; a signal receiving unit that moves in a direction in which the transmission line extends without contacting the transmission line of the signal transmitting unit; It is equipped with wireless communication is performed by electromagnetic coupling between the signal transmitting unit and the signal receiving unit; Transmission system.

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