WO2020041968A1 - Surface wave conversion coupling device and surface wave communication system - Google Patents

Abstract

Provided by the present application are a surface wave conversion coupling device and a surface wave communication system. The coupling device for transmitting a surface wave according to the present application comprises: a printed circuit board (PCB) and a cylindrical conductor, wherein the PCB comprises a ground layer and a signal layer, and the ground layer is disposed above the signal layer. The signal layer is provided thereon with a signal line, and the two ends of the signal line are bent at one position of the signal line, and then are closed to form a semi-closed area. An insertion hole is formed on the ground layer, and the insertion hole is located in the semi-closed area. The cylindrical conductor is vertically inserted into the insertion hole to contact the signal line. The cylindrical conductor is of a structure capable of maintaining the propagation of cylindrical surface waves. The structure of the coupling device used in the present application is easy to process and fix, thereby achieving high-energy coupling of planar surface waves to cylindrical surface waves.

Description

Surface wave conversion coupling device and surface wave communication system Technical field

The present application relates to communication technology, and in particular, to a surface wave conversion coupling device and a surface wave communication system.

Background technique

In high-speed communication technology, a signal transmitting chip on a printed circuit board (Printed Circuit Board, abbreviated as PCB) on the signal transmitting side sends out a high-speed signal, and transmits the signal through the high-speed signal line on the PCB and the high-speed cable in the space. The high-speed signal line on the receiving side PCB is finally received by the receiving chip on the PCB to complete the entire high-speed signal transmission process.

With the increase of communication transmission rate, the demand for large bandwidth of communication technology is more obvious. Because surface wave communication has high bandwidth and low attenuation transmission characteristics, it is considered for high-speed signal transmission. On the signal transmitting side, the transmitting chip sends a high-speed signal. The high-speed signal is transmitted through a PCB trace to form a surface wave transmission. After coupling the surface wave to a cylindrical surface wave, it can support the surface of cables such as copper cables and dielectric cables. The cylindrical surface wave is propagated. The cable only plays a role in guiding the propagation of the cylindrical surface wave. There is no current transmission in the cable itself. On the signal receiving side, the received cylindrical surface wave is coupled to a plane surface wave, and then passes through the PCB. The trace finally enters the receiving chip.

In the related art, coupling a planar surface wave to a cylindrical surface wave is achieved by an integrated horizontal transfer coupling device. However, such an integrated coupling device is difficult to process and cannot withstand large tensile forces, and is not suitable for long-distance transmission.

Summary of the Invention

The present application provides a surface wave conversion coupling device and a surface wave communication system, which are easy to process and fix, and achieve high-energy coupling of a planar surface wave to a cylindrical surface wave.

In a first aspect, the present application provides a coupling device for transmitting a surface wave, which is composed of a PCB and a cylindrical conductor. The PCB has a two-layer structure, the upper layer is a ground layer, and the lower layer is a signal layer. The signal line is set on the signal layer, and the two ends of the signal line are bent at a certain position and close to a semi-closed area. An insertion hole is provided on the ground layer, and the insertion hole is located in a semi-closed area. The cylindrical conductor is vertically inserted into the insertion hole to contact the signal line. The cylindrical conductor adopts a structure capable of maintaining the propagation of cylindrical surface waves.

The coupling device of the present application divides the PCB and the conductor into two parts, which is easy to process. The two parts are connected together by a plug-in method, which is easy to fix. The semi-closed area surrounded by the signal lines on the PCB and the sustainable cylindrical surface wave used by the conductor. The combination of the propagating structure can ensure the high-energy coupling of the plane surface wave to the cylindrical surface wave and maintain the low loss on the conductor surface, which is suitable for long-distance transmission.

In a possible implementation manner, the width of the bent portion near the signal line in the semi-closed region is greater than the width of the two ends near the signal line in the semi-closed region.

The semi-closed area surrounded by the signal line in this application presents a structure with a gradually changing width. The width of the bent portion near the signal line is larger, and the width near the two ends of the signal line is smaller. Such a structure realizes the transformation process of increasing impedance. Complete the transition from TEM mode to TM mode.

In a possible implementation manner, the insertion hole covers a bent portion of the signal line.

In this application, the insertion hole covers the bent portion of the signal line, so that the cylindrical conductor inserted into the insertion hole can be in good contact with the signal line and easily propagate surface waves.

In a possible implementation manner, a plurality of ground vias penetrating the ground layer and the signal layer are further provided on the ground layer and the signal layer, and the plurality of ground vias surrounds the outside of the signal line and the insertion hole. The ground via is filled with a metal medium, or a metal medium is provided on the hole of the ground via.

In this application, multiple ground vias are provided around the outside of the signal line and the insertion hole, the purpose of which is to transmit signals from the signal layer to the ground vertically and reduce signal energy radiation.

In a possible implementation manner, one end of the cylindrical conductor inserted into the insertion hole may adopt a periodic groove structure or a vertebral body structure. The material of the periodic groove structure includes metal, plastic, or polyvinyl chloride (PVC) dielectric. The body structure includes a metal outer wall and a filling medium.

In this application, both the periodic groove structure and the vertebral body structure can well convert a plane surface wave into a cylindrical surface wave, and can be introduced into a cable for propagation with little energy loss.

In a second aspect, the present application provides a surface wave communication system, including: a transmitting device and a receiving device; wherein the transmitting device and the receiving device are both provided with the surface wave coupling device of the first aspect; The transmitting device and the receiving device are connected by a cable. One end of the cable is connected to a cylindrical conductor in the coupling device for transmitting surface waves on the transmitting device, and the other end of the cable is connected to the transmitting surface wave on the receiving device. Coupling on a cylindrical conductor.

The surface wave communication system of the present application maintains the high energy of the surface wave on the surface of the cable for propagation through the coupling device for transmitting the surface wave in the present application, and realizes long-distance transmission of signals based on the characteristics of large bandwidth and low loss of the surface wave technology.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to explain the technical solution in the present application or the prior art more clearly, the drawings used in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are Some embodiments of the application, for those of ordinary skill in the art, can obtain other drawings according to these drawings without paying creative labor.

FIG. 1 is a schematic diagram of a high-speed communication application scenario based on surface wave technology;

2 is a schematic diagram of a cylindrical surface wave propagation form on a periodic groove structure;

FIG. 3 is a schematic diagram of the transmission effect of surface waves of different frequencies on a periodically grooved structured conductor;

4 is a surface wave propagation device in the prior art;

5a is a schematic diagram of the overall structure of a first embodiment of a coupling device for transmitting a surface wave;

5b is a schematic plan view of a PCB of a first embodiment of a coupling device for transmitting a surface wave according to the present application;

5c is a schematic bottom structural view of a PCB of a first embodiment of a coupling device for transmitting a surface wave;

5d is a top perspective view of a PCB of a first embodiment of a coupling device for transmitting a surface wave of the present application;

6 is a schematic diagram of an overall structure of a second embodiment of a coupling device for transmitting a surface wave according to the present application;

FIG. 7 is a schematic structural diagram of a first embodiment of a surface wave communication system of the present application.

detailed description

In order to make the purpose, technical solution, and advantages of this application clearer, the technical solution in this application will be described clearly and completely in combination with the drawings in this application. Obviously, the described embodiments are part of the embodiments of this application. , Not all examples. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

Figure 1 is a schematic diagram of a high-speed communication application scenario based on surface wave technology. As shown in Figure 1, on the signal transmitting side, the transmitting chip sends a high-speed signal. The high-speed signal is transmitted through the PCB trace to form a planar surface wave on the PCB. After coupling the planar surface wave into a cylindrical surface wave, the copper cable is introduced through the conductor. And dielectric cables carry cylindrical surface wave propagation; on the signal receiving side, the received cylindrical surface wave is coupled to a planar surface wave on the PCB, and finally enters the receiving chip through the PCB trace, completing the surface wave technology High-speed signal transmission.

FIG. 2 is a schematic diagram of the propagation form of a cylindrical surface wave on a periodic groove structure. As shown in Figure 2, the cylindrical periodic groove structure can well maintain the surface wave propagation. This is a structure with frequency selection, that is, the size of the periodic groove and the propagation frequency of the supported surface wave correspond one-to-one. of. FIG. 3 is a schematic diagram of the transmission effect of surface waves of different frequencies on a periodically grooved structured conductor. As shown in Fig. 3, this grooved conductor is most suitable for the propagation of surface waves with a frequency of 0.6 THz, and the energy of the surface waves at this frequency can be transmitted well along the surface of the conductor to the opposite end. Although the 0.4THz surface wave can also propagate to the opposite end, the energy loss during the propagation process is large, and the propagation performance is low. The 1.0THz surface wave is completely unsuitable for this groove size, and a large amount of energy is radiated as soon as the conductor energy is introduced. It can be seen that, as long as the periodic groove structure is used to propagate surface waves of an adapted frequency, it is a good structure suitable for surface wave propagation.

FIG. 4 is a surface wave propagation device in the prior art. As shown in Figure 4, the surface wave propagation device uses an integrated horizontal transfer structure, and the left and right transmission and reception use a planar excitation surface wave structure, with a cylindrical conductor in the middle. Both are integrally formed, both are located in the same plane to achieve the plane. Surface wave is transformed into the purpose of cylindrical surface wave propagating on a cylindrical conductor. However, such an integrated coupling device is difficult to process and cannot withstand large tensile forces, and is not suitable for long-distance transmission.

In order to solve the above problems, the present application provides a coupling device for transmitting a surface wave, which is composed of a PCB and a cylindrical conductor. The PCB adopts a two-layer structure, the upper layer is a ground layer, and the lower layer is a signal layer. The signal line is arranged on the signal layer and has a curved shape. The two ends of the signal line are close to form a semi-closed area. An insertion hole is provided on the ground layer, and the insertion hole is located in a semi-closed area. The cylindrical conductor is vertically inserted into the insertion hole to contact the signal line. The cylindrical conductor adopts a structure capable of maintaining the propagation of cylindrical surface waves. The characteristic of surface wave is that its electromagnetic field distribution is mainly concentrated in the medium constituting the waveguide and the area near the surface. The electromagnetic field outside the medium decreases exponentially with increasing distance from the surface. Therefore, to achieve effective surface wave transmission, it is necessary to make The surface of the waveguide has a large reactance. When the surface wave is introduced into the cable from the PCB plane, the structure that can maintain the propagation of the cylindrical surface wave can achieve the purpose of high coupling and low loss. The coupling device of the present application divides the PCB and the conductor into two parts, which is easy to process. The two parts are connected together by a plug-in method, which is easy to fix. The progressive structure of the signal line on the PCB and the conductor used to maintain the cylindrical surface wave propagation. The combination of structures can ensure the high-energy coupling of plane surface waves to cylindrical surface waves and maintain low loss on the conductor surface, which is suitable for long-distance transmission.

The following uses several specific embodiments to describe the technical solution of the present application in detail.

5a is a schematic diagram of the overall structure of a first embodiment of a surface wave coupling device of the present application, FIG. 5b is a schematic plan view of a PCB of the first embodiment of a surface wave coupling device of the present application, and FIG. 5c is a surface wave coupling device of the present application. The bottom view of the PCB of the first embodiment is schematically shown in FIG. 5D, which is a top perspective view of the PCB of the first embodiment of the coupling device for transmitting a surface wave. Looking at the combination of Figs. 5a-5d, the coupling device for transmitting surface waves includes a PCB and a cylindrical conductor, wherein the PCB adopts a two-layer structure, the upper layer is a ground layer, and the lower layer is a signal layer.

The signal layer is provided with a signal line. The two ends of the signal line are bent to form a semi-closed area after being bent. The width of the bent portion near the signal line in the semi-closed area is greater than that of the two ends of the signal line in the semi-closed area. Width, showing a gradual structure. The bent portion is a small portion where the bent point on the signal line is located.

An insertion hole is provided on the ground layer, and the insertion hole is located in the semi-closed area and completely covers the bent portion of the signal line.

The cylindrical conductor is vertically inserted into the insertion hole to contact the signal line. The cylindrical conductor in the embodiment of the present application adopts a periodic groove structure. This periodic groove structure has the performance of frequency selection. The size of the periodic groove is corresponding to the propagation frequency of the surface wave supported. See FIG. 4. As long as the periodic groove structure is used to propagate surface waves of a suitable frequency, plane surface waves can be well converted into cylindrical surface waves, and they can be introduced into the cable for propagation with little energy loss. The periodic groove structure can be made of metal material to form a unified structure with the connected conductors, or it can be made of other dielectric materials, such as plastic or polyvinyl chloride (PVC), and then connected to the metal material conductor.

The surface wave transmission mode is a transverse magnetic (Transverse Magnetic) (TM) mode. This mode is derived from the Transverse Electric Magnetic (TEM) mode that gradually increases impedance. The signal line on the PCB has a gradual structure to realize the transformation process of increasing impedance. The periodic groove structure adopted by cylindrical conductors can transform plane surface waves into cylindrical surface waves and maintain low loss on the surface of the conductor, which is suitable for long-distance transmission.

In order to transmit the signal vertically from the signal layer to the ground layer, a plurality of ground vias penetrating the ground layer and the signal layer are also provided on the ground layer and the signal layer, and the plurality of ground vias surround the outside of the signal line and the insertion hole. The ground via is filled with a metal medium, or a metal medium is provided on the hole of the ground via.

FIG. 6 is a schematic diagram of the overall structure of a second embodiment of a coupling device for transmitting a surface wave. As shown in FIG. 6, it is different from the first embodiment shown in FIGS. 5 a to 5 d in that the end of the insertion hole on the cylindrical conductor in the embodiment of the present application adopts a vertebral structure, and the vertebral structure includes a metal outer wall and a filling medium .

In addition to the above two structures, one end of the cylindrical conductor inserted into the insertion hole may adopt other structures. Any structure that can maintain the propagation of cylindrical surface waves can be used in this application, which is not specifically limited.

FIG. 7 is a schematic structural diagram of a first embodiment of a surface wave communication system of the present application. As shown in FIG. 7, the system includes a transmitting-end device and a receiving-end device, wherein the transmitting-end device and the receiving-end device are each provided with a coupling device for transmitting a surface wave in any of the foregoing embodiments. The transmitting device and the receiving device are connected by a cable. One end of the cable is connected to a cylindrical conductor in the coupling device for transmitting surface waves on the transmitting device, and the other end of the cable is connected to the transmitting surface wave on the receiving device. Coupling on a cylindrical conductor.

The surface wave communication system of the present application maintains the high energy of the surface wave on the surface of the cable for propagation through the coupling device for transmitting the surface wave in the present application, and realizes long-distance transmission of signals based on the characteristics of large bandwidth and low loss of the surface wave technology.

Finally, it should be noted that the above embodiments are only used to describe the technical solution of the present application, rather than limiting it. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: The technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features are equivalently replaced; and these modifications or replacements do not deviate the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present application. range.

Claims (8)

A coupling device for transmitting surface waves, comprising: a printed circuit board PCB and a cylindrical conductor; The PCB includes a ground layer and a signal layer, and the ground layer is disposed on the signal layer; A signal line is provided on the signal layer, and two ends of the signal line are bent at a position of the signal line and close to surround a semi-closed area; An insertion hole is provided on the ground layer, and the insertion hole is located in the semi-closed area; The cylindrical conductor is vertically inserted into the insertion hole to be in contact with the signal line; The cylindrical conductor adopts a structure capable of maintaining the propagation of a cylindrical surface wave. The device according to claim 1, wherein a width of a bent portion near the signal line in the semi-closed area is greater than a width of two ends near the signal line in the semi-closed area. The device according to claim 1 or 2, wherein the insertion hole covers a bent portion of the signal line. The device according to any one of claims 1-3, wherein a plurality of ground vias penetrating the ground layer and the signal layer are further provided on the ground layer and the signal layer, and A plurality of ground vias surrounds the outside of the signal line and the insertion hole; the ground vias are filled with a metal dielectric. The device according to any one of claims 1-4, wherein an end of the cylindrical conductor inserted into the insertion hole adopts a periodic groove structure. The device according to claim 5, wherein the material of the periodic groove structure comprises metal, plastic or polyvinyl chloride (PVC) medium. The device according to any one of claims 1-4, wherein an end of the cylindrical conductor inserted into the insertion hole adopts a vertebral body structure, and the vertebral body structure includes a metal outer wall and a filling medium. A surface wave communication system, comprising: a transmitting device and a receiving device; wherein, A coupling device for transmitting a surface wave according to any one of claims 1 to 7 is provided on the transmitting end device and the receiving end device; The transmitting end device and the receiving end device are connected by a cable, and one end of the cable is connected to a cylindrical conductor in a coupling device for transmitting a surface wave on the transmitting end device, and the other end of the cable Connected to a cylindrical conductor in a coupling device for transmitting a surface wave on the receiving end device.

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