Gap waveguide transmission device based on artificial surface plasmon and manufacturing method thereof

Abstract

The invention discloses a gap waveguide transmission device based on artificial surface plasmon and a manufacturing method thereof, and the device comprises two waveguide transmission structures which are oppositely arranged, a transmission channel is defined by the two waveguide transmission structures, a gap is formed in the joint surface of the two waveguide transmission structures, and a conductive layer is arranged on the inner wall of the transmission channel. A corrugated groove is formed in the periphery of the side wall, with the gap, of the transmission channel, protrusions and grooves which are periodically or periodically arranged at intervals are formed in the face, facing the outer side of the side wall, of the corrugated groove, conductive layers are arranged on the surfaces of the protrusions and the grooves of the corrugated groove, and the conductive layers are electrically connected to the conductive layer on the inner wall of the transmission channel. Through the arrangement of the corrugated groove, when a gap exists between the first waveguide transmission structure and the second waveguide transmission structure, electromagnetic energy is bound around the corrugated groove, and therefore it is guaranteed that the electromagnetic energy can be completely transmitted in the expected direction.

Description

Technical Field

[0001] The present invention relates to a novel microwave / millimeter wave device, which is particularly suitable for microwave / millimeter wave communication, millimeter wave radar or antenna system, and specifically to a gap waveguide transmission device based on artificial surface plasmon and a manufacturing method thereof. Background Art

[0002] In recent years, RF circuits have been used in products with electrical signal transmission functions, especially those involving information transmission. According to the RF operating frequency, it can be divided into: low-frequency scenarios and high-frequency scenarios. In low-frequency scenarios, information is transmitted along wires or cables; in high-frequency scenarios, information can be transmitted wirelessly through radio waves or along low-loss transmission lines. According to the functions implemented by the product, whether it is a low-frequency scenario or a high-frequency scenario, a medium for transmitting signals is required.

[0003] In the past, the products we needed in our lives did not have high requirements for the rate and amount of information transmission, and the working frequency of transmitting information was also low, so conventional transmission lines could meet the application needs at that time.

[0004] In recent years, with the explosive growth of data volume in new Internet services such as smart cities and Internet of Vehicles, data transmission requires communication technology with a transmission rate comparable to that of optical fiber, with its advantages of high bandwidth, high speed, high reliability, low latency, low power consumption, and large connections, which has become the product demand at this time.

[0005] To achieve high bandwidth, high reliability, low latency, low power consumption, and large-connection information transmission, the applied frequency must be high frequency (millimeter wave band, THz band, etc.).

[0006] In the high frequency band, commonly used transmission lines include microstrip lines, coaxial lines, strip lines, differential lines, coplanar waveguides (CPW), dielectric integrated waveguides (SIW) and air waveguides, among which

[0007] Microstrip line is the most common and commonly used transmission line, which transmits quasi-TEM waves. Its structure is that the strip conductor is located on the upper surface of the dielectric plate, and the lower surface of the dielectric plate is a metal surface. The size of the metal surface is generally consistent with the size of the dielectric, but there may be inconsistencies in special cases. If this transmission line is used for high-frequency transmission, the transmission efficiency and quality will be seriously reduced due to dielectric loss. At present, high-frequency boards with lower high-frequency dielectric loss can also be used, but these boards are expensive and increase the cost of the product. In addition, since the microstrip line is exposed on the surface of the PCB board, if its length is greater than several wavelengths, there will be additional radiation that affects the transmission efficiency and quality.

[0008] Coaxial line is also a commonly used transmission line. It transmits TEM waves. Its structure is composed of two coaxial cylindrical conductors. The dielectric material is filled between the two cylindrical conductors. Like microstrip line, when working at high frequency, the transmission efficiency and quality will be seriously reduced due to dielectric loss. In addition, the volume of coaxial line is large, which is not conducive to the application of miniaturized products.

[0009] Stripline is a commonly used microwave transmission line that transmits TEM waves. Its structure is to place a guide strip between two ground plates. Stripline can be seen as an evolution of coaxial line. It optimizes the volume of the transmission line structure (lower profile), but it is not suitable for high frequencies due to dielectric loss.

[0010] Differential lines have three signal transmission modes: single-ended mode, common mode and differential mode. They are very suitable for high-speed transmission scenarios, but they will also reduce transmission efficiency and quality due to medium loss.

[0011] Coplanar waveguide transmits quasi-TEM waves. Compared with microstrip lines, it solves the radiation problem of microstrip lines. However, at the high-frequency end, the presence of the medium will still cause dielectric loss, reducing transmission efficiency and quality.

[0012] The dielectric integrated waveguide originates from the stacked waveguide. Its structure is to add two rows of metal vias with the same radius on both sides of the double-sided copper-clad dielectric board. The spacing between two adjacent metal vias is equal. If this structure is used at high frequencies, the efficiency and quality of information transmission will still be reduced due to dielectric loss.

[0013] Air waveguides can be divided into cylindrical waveguides and rectangular waveguides according to their structure. Cylindrical waveguides and rectangular waveguides are enclosed by metal outer walls with circular or rectangular cross-sections. Electromagnetic waves propagate in the middle of them, but this structure has very strict requirements on processing and manufacturing.

[0014] In summary, traditional transmission lines have limitations in their applications. When working in the millimeter wave frequency band, the dielectric loss will increase rapidly, and the waveguide will also reduce the transmission efficiency and quality of electromagnetic waves due to manufacturing process problems. Summary of the invention

[0015] In view of the problems raised in the above background technology, the purpose of the present invention is to provide a gap waveguide transmission device based on artificial surface plasmons that is very suitable for working in the millimeter wave frequency band, as well as other millimeter wave devices based on this technology, such as antennas.

[0016] To achieve the above technical objectives, the technical solutions adopted by the embodiments of the present invention are as follows:

[0017] The gap waveguide transmission device based on artificial surface plasmon includes: two waveguide transmission structures arranged opposite to each other, the two waveguide transmission structures form a transmission channel, the connecting surfaces of the two waveguide transmission structures have a gap, the inner wall of the transmission channel has a conductive layer, the side wall of the transmission channel with the gap is provided with a corrugated groove on the periphery, the side of the corrugated groove facing the outer side of the side wall has protrusions and grooves arranged at periodic or quasi-periodic intervals, the protrusion and groove surfaces of the corrugated groove have a conductive layer, and the conductive layer is electrically connected to the conductive layer of the inner wall of the transmission channel.

[0018] A method for manufacturing a gap waveguide transmission device based on artificial surface plasmons comprises:

[0019] Two transmission structures are provided, wherein a surface of at least one waveguide transmission structure opposite to the other waveguide transmission structure is provided with a groove, and a conductive layer is provided on the opposite surfaces of the two transmission structures, and the conductive layer covers the groove;

[0020] A corrugated groove is formed on the outer wall of the groove, and the corrugated groove is fixedly electrically connected to the conductive layer of at least one of the two waveguide transmission structures; the two waveguide transmission structures are installed so that the conductive layer covering the groove and the conductive layer of the other waveguide transmission structure form a strip-shaped waveguide transmission channel.

[0021] The gap waveguide transmission device based on artificial surface plasmon of the present invention has the following advantages: 1. It can simplify the assembly process and flow of the product; 2. It can also ensure extremely excellent electrical performance within a larger assembly tolerance redundancy; 3. The simplified design and simplified assembly process can bring low-cost advantages; 4. It greatly improves the performance of waveguide transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] For better illustration, the present invention may be further described by way of non-limiting embodiments given in the accompanying drawings;

[0023] Figure 1 It is a three-dimensional diagram of a gap waveguide transmission device based on artificial surface plasmon according to the first embodiment of the present invention;

[0024] Figure 2 It is a side schematic diagram of a gap waveguide transmission device based on artificial surface plasmon according to the first embodiment of the present invention;

[0025] Figure 3 It is a front schematic diagram of the second metal layer of the gap waveguide transmission device based on artificial surface plasmon in the first embodiment of the present invention;

[0026] Figure 4 A front view of a corrugated groove for realizing artificial surface plasmons in a gap waveguide transmission device based on artificial surface plasmons of the present invention;

[0027] Figure 5 For the present invention Figure 4 Schematic diagram of the equivalent model in;

[0028] Figure 6 It is a side schematic diagram of a gap between the first metal layer and the second metal layer of the gap waveguide transmission device based on artificial surface plasmon in the first embodiment of the present invention;

[0029] Figure 7 It is a side schematic diagram of a gap waveguide transmission device based on artificial surface plasmon according to the second embodiment of the present invention;

[0030] Figure 8 It is a side schematic diagram of a gap waveguide transmission device based on artificial surface plasmon according to the third embodiment of the present invention;

[0031] Fig. 9 An exploded view of a gap waveguide transmission device based on artificial surface plasmons according to a fourth embodiment of the present invention;

[0032] Fig.10 This is a back view of a gap waveguide transmission device based on artificial surface plasmon according to the fourth embodiment of the present invention;

[0033] Fig.11 This is an insertion loss diagram of the gap waveguide transmission device based on artificial surface plasmons before and after the gap exists between the first metal layer and the second metal layer of the fourth embodiment of the present invention;

[0034] Fig.12 It is a perspective side view of a gap waveguide transmission device based on artificial surface plasmon according to Embodiment 5 of the present invention;

[0035] Fig.13 It is a schematic cross-sectional view of a gap waveguide transmission device based on artificial surface plasmon according to Embodiment 5 of the present invention;

[0036] Fig.14 This is a cross-sectional schematic diagram of a gap between the first metal layer and the second metal layer of a gap waveguide transmission device based on artificial surface plasmon according to Embodiment 5 of the present invention;

[0037] Fig.15 This is an insertion loss diagram before and after the gap exists between the first metal layer and the second metal layer of the gap waveguide transmission device based on artificial surface plasmon according to the fifth embodiment of the present invention. DETAILED DESCRIPTION

[0038] In order to enable those skilled in the art to better understand the content of the present invention, the technical solution of the present invention is further described in more detail below in conjunction with the accompanying drawings. At the same time, it should be understood that the solution of implementing the present invention in other forms should not be limited by the embodiments described herein.

[0039] First, the artificial surface plasmon technology of the present invention is explained. Surface plasmons (surface plasmon polaritons) are a kind of surface wave mode in the optical frequency band that propagates along the interface between the medium and the metal conductor. This mode is formed by the interaction between the light or other electromagnetic waves bounded on its surface and the free electrons of the metal. It has the characteristics of propagating along the tangent direction of the interface and exponentially decaying in the normal direction, so it can tightly bind the electromagnetic energy around the interface. Surface plasmons can generate, distribute, modulate and detect light on a subwavelength scale, and have a huge driving effect on the development of photonic integrated circuits (PIC) technology. However, when the frequency is reduced to the far infrared, terahertz and millimeter wave bands, the properties of metals are closer to perfect electric conductors (PEC) rather than plasmas with negative dielectric constants, so surface plasmons cannot be supported. In order to solve this problem, the present invention proposes to realize an electromagnetic metamaterial by designing a special periodic or quasi-periodic structure on the outer surfaces of the narrow walls on both sides of the gap waveguide transmission device, thereby supporting a mode with similar properties to surface plasmons, namely artificial surface plasmons (spoof surface plasmon polaritons, SSPP).

[0040] The gap waveguide transmission device based on artificial surface plasmon of the present invention comprises: two waveguide transmission structures arranged opposite to each other, the two waveguide transmission structures enclose a transmission channel, the connecting surfaces of the two waveguide transmission structures have a gap, the inner wall of the transmission channel has a conductive layer, the outer periphery of the side wall of the transmission channel with the gap is provided with a corrugated groove, the side of the corrugated groove facing the outer side of the side wall has protrusions and grooves arranged at periodic or quasi-periodic intervals, the protrusion and groove surfaces of the corrugated groove have a conductive layer, and the conductive layer is electrically connected to the conductive layer of the inner wall of the transmission channel.

[0041] Optionally, the grooves and protrusions of the corrugated grooves have the same width and interval, and the conductive layer on the surface of the corrugated grooves is a metal layer.

[0042] Optionally, one of the waveguide transmission structures is provided with a groove constituting a waveguide transmission channel, and the surface of the other waveguide transmission structure opposite to the groove is a smooth surface without any protrusions.

[0043] Optionally, the conductive layer provided on the waveguide transmission structure is a metal layer.

[0044] Optionally, the two waveguide transmission structures are both provided with corresponding grooves, and the corresponding grooves constitute a waveguide transmission channel.

[0045] Optionally, the concave-convex direction of the corrugated groove is perpendicular to the side wall of the waveguide transmission channel.

[0046] Optionally, the corrugated groove is electrically connected to the conductive layer of the side wall of the waveguide transmission channel, and the height of the corrugated groove and the groove side wall in the same direction are the same.

[0047] Optionally, the width of the side wall of the groove along the direction perpendicular to the waveguide transmission channel ranges from 0.1mm to 5mm, the height ranges from 0.1mm to 5mm, the depth of the corrugated groove is set in the range of 0.1mm to 2mm; the width of the corrugated groove is set in the range of 0.1mm to 2mm; the width of the raised part in the middle of adjacent corrugated grooves is set in the range of 0.1mm to 2mm; the height of the corrugated groove is between 0.1mm and 5mm.

[0048] Optionally, a conductor device is further provided in the groove, wherein the conductor device is fixedly and electrically connected to a conductive layer of at least one of the two waveguide transmission structures, and the conductor device is used to form the waveguide transmission path.

[0049] Optionally, the conductor device is a single waveguide ridge or a double waveguide ridge, one end of the waveguide ridge is used to connect to the matching transition of the integrated circuit module, and the other end is also used to connect to the matching transition of the integrated circuit module.

[0050] Optionally, the conductor device includes two opposite conductor devices respectively connected to the conductive layers of two waveguide transmission structures, and the two conductor devices are in non-electrical connection.

[0051] Optionally, the conductor device is fixedly connected to the bottom surface of the groove and is located at the center of the bottom surface of the groove and is symmetrically distributed along the center line in the transmission direction, or the conductor device is fixedly connected to the waveguide transmission structure without the groove, and in the vertical projection, the conductor device is located in the middle of the bottom surface of the groove.

[0052] Optionally, at least one of the two waveguide transmission structures is further provided with a protruding metal structure having the same height as the side wall of the groove, and the protruding metal structure is provided with screw holes having the same number as the screw holes on the other metal layer.

[0053] Optionally, the waveguide transmission structure and the conductive layer are an integrated metal structure, and the corrugated groove and the conductive layer on its surface are an integral metal structure.

[0054] Optionally, the conductor component is a rectangular waveguide ridge, and the waveguide ridge is straight, curved or stepped.

[0055] Optionally, the corrugated grooves located on two opposite side walls of the groove are electrically connected through the side walls of the groove and a conductive layer of one of the two waveguide transmission structures.

[0056] Optionally, one of the two waveguide transmission structures is further provided with at least one waveguide opening, and the waveguide opening is used for transmitting radiation to the waveguide transmission line and receiving radiation from the waveguide transmission line.

[0057] Optionally, the shapes of the protrusions and grooves of the corrugated groove are any one of rectangular, triangular, semicircular, trapezoidal and elliptical.

[0058] The gap waveguide device of the present invention includes two metal layers arranged therebetween and two groups of periodically or quasi-periodically arranged corrugated grooves, wherein the corrugated grooves are fixedly electrically connected to the metal layer of at least one waveguide transmission structure, so as to prevent wave propagation in the working frequency band in directions other than along the intended waveguide path when there is a gap between the two waveguide transmission structures. The two waveguide transmission structures may be electrically connected without a gap, or the two waveguide transmission structures may be electrically connected partially without a gap, or the two waveguide transmission structures may be assembled in a non-electrically connected manner with a gap between them.

[0059] In such Figure 1 and Figure 2 In the embodiment 1 shown, a gap waveguide transmission device based on artificial surface plasmon is schematically illustrated. Two waveguide transmission structures are arranged opposite to each other. In this embodiment, the two waveguide transmission structures are respectively a first waveguide transmission structure 1 and a second waveguide transmission structure 2. The two waveguide transmission structures enclose a waveguide transmission channel. The connecting surfaces of the two waveguide transmission structures have a gap gap. The inner wall of the transmission channel has a conductive layer. The outer periphery of the side wall of the transmission channel with the gap is provided with a corrugated groove 7. The corrugated groove 7 has protrusions and grooves arranged at periodic or quasi-periodic intervals on one side facing the outer side of the side wall. The protrusions and grooves of the corrugated groove have a conductive layer on the surface, and the conductive layer is electrically connected to the conductive layer of the inner wall of the transmission channel. The gap waveguide transmission device includes a first waveguide transmission structure 1 and a second waveguide transmission structure 2. In this embodiment, the two waveguide transmission structures are arranged to be separated by a gap gap. When gap=0, the first waveguide transmission structure 1 and the second waveguide transmission structure 2 are in electrical connection without a gap; and when gap>0, a gap is formed between the first waveguide transmission structure 1 and the second waveguide transmission structure 2. In this embodiment, the first waveguide transmission structure 1 and the second waveguide transmission structure 2 are arranged in parallel. The two waveguide transmission structures can be electrically connected without a gap, or the two waveguide transmission structures can be electrically connected partially without a gap, or the two waveguide transmission structures can be assembled in a non-electrically connected manner with a gap between them.

[0060] The second waveguide transmission structure 2 is provided with a groove 8, wherein the bottom surface of the groove 8 is parallel to the second waveguide transmission structure 2, and the bottom surface and the side surface have a conductive layer, which is a metal layer in this embodiment, specifically metal copper, gold, silver, etc.; the two side walls 91 and 92 of the groove 8 are perpendicular or non-perpendicular to the bottom surface, and the two side walls 91 and 92 are symmetrically distributed on both sides of the groove 8. In one embodiment, one of the waveguide transmission structures is provided with a groove constituting a waveguide transmission channel, and the surface of the other waveguide transmission structure opposite to the groove is a smooth surface without any protrusions, preferably, its thickness is greater than 0.1mm. The conductive layer provided on the waveguide transmission structure can also be a conductive layer of other metal layers or other materials.

[0061] In another embodiment, the two waveguide transmission structures are both provided with corresponding grooves, and the corresponding grooves are arranged relative to each other to form a strip-shaped waveguide transmission channel.

[0062] In the gap waveguide transmission device of the first embodiment, in order to facilitate processing and manufacturing, the first waveguide transmission structure 1 serves as one of the wide sides of the waveguide channel, and the two side walls 91 and 92 of the groove 8 in the second waveguide transmission structure 2 serve as the narrow sides of the waveguide channel, and the bottom surface of the groove 8 serves as the other wide side of the waveguide channel. In other words, the first waveguide transmission structure and the second waveguide transmission structure form a waveguide transmission channel, wherein the bottom width of the groove 8 of the second waveguide transmission structure is greater than the height of the side wall. Thus, the groove 8 of the second waveguide transmission structure 2 and the first waveguide transmission structure 1 form a waveguide transmission channel for transmitting electromagnetic energy of the device.

[0063] like Figure 1 As shown, the upper and lower surfaces of the first waveguide transmission structure 1 of the first embodiment of the present invention are smooth metal surfaces without any protrusions, and the material thereof can be stamped copper, CNC or plastic molded surface metal. In addition, in order to ensure the structural strength and its flatness, its thickness can be set to be greater than 0.1 mm. In other embodiments, corresponding grooves can also be set on the surface opposite to the groove of the first waveguide transmission structure 1. In other embodiments, the first waveguide transmission structure can also be other insulating materials, and a conductive layer or a metallized layer is formed on its surface.

[0064] In order to better electrically connect the first waveguide transmission structure 1 to the second waveguide transmission structure 2, in the first embodiment, a plurality of screw holes 4 are provided on the first waveguide transmission structure 1. Figure 1In the embodiment, the screw holes 4 on the first waveguide transmission structure 1 are arranged on both sides of the waveguide transmission channel. The screw holes 4 on both sides of the waveguide transmission channel may be equal in number or unequal in number, and may be symmetrical or unequal about the waveguide transmission channel. It should be noted that in order to ensure better electrical connection between the first waveguide transmission structure 1 and the second waveguide transmission structure 2, there should be at least four screw holes 4, which should be arranged at the four corners of the first waveguide transmission structure 1 respectively.

[0065] In addition to the above-mentioned method of fixing the first waveguide transmission structure 1 and the second waveguide transmission structure 2 by screwing, the first waveguide transmission structure 1 and the second waveguide transmission structure 2 may also be fixed by riveting or welding.

[0066] In one embodiment, a stepped metal protrusion may be provided to better arrange the screw holes. Figure 1 and Figure 2 A step 111 and a step 2 112 are further provided on the front side of the second waveguide transmission structure 2, and screw holes 5 are provided on the step 111 and the step 2 112. The positions and number of the screw holes 5 correspond one to one with the positions and number of the screw holes on the first waveguide transmission structure 1, so that the first waveguide transmission structure 1 and the second waveguide transmission structure 2 can be better fixed together by the screws 3.

[0067] In addition, in order to reduce the overall weight of the product, a groove 101 may be reserved between step 111 and side wall 91, and a groove 102 may be reserved between step 112 and side wall 92.

[0068] like Figure 1 and 2, periodic or quasi-periodic corrugated grooves 7 are also arranged on the outer sides of the waveguide transmission channel sidewall 1 91 and the waveguide transmission channel sidewall 2 92 on both sides of the groove 8, and the corrugated grooves 7 are fixedly connected to the second waveguide transmission structure 2, so as to form artificial surface plasmons to prevent the propagation of electromagnetic waves in other directions except along the expected electromagnetic transmission path in the working frequency band, and all the corrugated grooves 7 are electrically connected to each other at least via the waveguide transmission structure to which they are fixedly connected at their bases, and wherein some of the corrugated grooves 7 in the corrugated grooves 7 are in electrical connection with the first waveguide transmission structure 1; and some of the corrugated grooves 7 in the corrugated grooves 7 are in non-electrical connection with the first waveguide transmission structure 1. In this embodiment, the concave-convex direction of the corrugated groove is perpendicular to the sidewall of the groove 8, and the corrugated grooves 7 are periodically or quasi-periodically arranged along the groove 8. In one embodiment, the width and interval of the grooves and convexities of the corrugated grooves are the same, and the conductive layer on the surface of the corrugated groove is a metal layer. In one embodiment, the corrugated groove is electrically connected to the conductive layer of the side wall of the waveguide transmission channel, and the height of the corrugated groove and the groove side wall in the same direction are the same.

[0069] In order to facilitate installation and better constrain the transmission signal, the height of the corrugated groove 7 can be set to be higher than, equal to or lower than the waveguide transmission channel side wall 91 and the waveguide channel side wall 92. In addition, the waveguide channel side wall 91 and the waveguide channel side wall 92 are of the same height, and their heights can be equal to or lower than the step 111 and the step 2 112, wherein the step 111 and the step 2 112 are of the same height.

[0070] In the gap waveguide transmission device described in Embodiment 1, at least one conductor device is also provided in the second waveguide transmission structure 2, and the conductor device is fixedly electrically connected to the second waveguide transmission structure 2 and is not electrically connected to the first waveguide transmission structure 1, so that the conductor device forms the waveguide transmission path, making the bandwidth of the transmitted signal more flexible.

[0071] The conductor device is a single waveguide ridge 6 or a double waveguide ridge. Its width is set between 0.1 mm and 2 mm, and its height is set between 0.1 mm and 2 mm. In addition, the waveguide ridge can be straight, curved, or other irregular shapes.

[0072] The rectangular waveguide ridge 6 of the present invention has one end used for connecting to the matching transition of the integrated circuit module, and the other end can also be used for connecting to the matching transition of the integrated circuit module.

[0073] In order to better work in the millimeter wave frequency band, the conductor device, namely the waveguide ridge 8, is generally set to have a width between 0.1 mm and 2 mm and a height between 0.1 mm and 2 mm.

[0074] like Figure 3and 4 , the corrugated groove 7 of embodiment 1, wherein the spacing p between adjacent corrugated grooves 7 is set in the range of 0.5mm-5mm; the depth h of the corrugated groove 7 is set in the range of 0.1mm-2mm; the width d of the corrugated groove 7 is set in the range of 0.1mm-2mm; the width of the raised part in the middle of adjacent corrugated grooves 7 is set in the range of 0.1mm-2mm; the height of the corrugated groove, that is, the height perpendicular to the second waveguide transmission structure, is set in the range of 0.1mm-5mm.

[0075] The shape of the corrugated groove can be rectangular, triangular, semicircular, trapezoidal, elliptical, etc. or other irregular shapes.

[0076] The width of the waveguide transmission channel side wall 1 91 and side wall 2 92 along the direction perpendicular to the electromagnetic transmission direction is set between 0.4 mm and 1 mm.

[0077] The first waveguide transmission structure 1 and the second waveguide transmission structure 2 may be completely electrically connected, partially electrically connected, or completely non-electrically connected in the projection area of ​​the corrugated groove 7 and the groove 8 .

[0078] The corrugated grooves 7 of the present invention are electrically connected to adjacent corrugated grooves 7 through the waveguide transmission channel sidewall 1 91 and the waveguide transmission channel sidewall 2 92 of the groove 8 and the second waveguide transmission structure 2. The waveguide transmission channel is suitable for transmitting microwaves, millimeter waves, terahertz, etc. with an operating frequency exceeding 1 GHz.

[0079] See also Figure 4 , is a top view of the outer corrugated groove of a narrow wall of the groove 8, wherein the width of each corrugated groove is d, the depth is h, and the spacing between adjacent grooves is p.

[0080] See also Figure 6 There is a gap between the first waveguide transmission structure 1 and the second waveguide transmission structure 2. This is also the case when the product is actually assembled, especially when the first waveguide transmission structure and the second waveguide transmission structure are fixed by screws. There will definitely be a gap. If there is a gap, there will be leakage of electromagnetic energy. The focus of the present invention is to prevent the leakage of electromagnetic energy through artificial surface plasmon technology. For example, when there is a gap between the first waveguide transmission structure and the second waveguide transmission structure, the energy will be bound by the corrugated grooves of the electrical connection on the outside of the side wall of the waveguide channel, and the electromagnetic energy will propagate along the desired transmission path, and the electromagnetic energy will decay rapidly in the direction perpendicular to the transmission path, so that the electromagnetic energy can be completely transmitted to the specified direction.

[0081] Figure 7This is the second embodiment in which the waveguide ridge 6 is not loaded inside the groove 8. Its working principle is the same as that of the first embodiment. When there is no gap between the first waveguide transmission structure 1 and the second waveguide transmission structure 2, it can be considered as a conventional rectangular air waveguide; and when there is a gap between the first waveguide transmission structure 1 and the second waveguide transmission structure 2, artificial surface plasmons are excited at this time, which will bind the electromagnetic energy around the corrugated groove and propagate along the desired electromagnetic transmission direction.

[0082] Figure 8 This is the third embodiment of the present invention. While there is a loading waveguide ridge 6 inside the groove 8, a waveguide ridge (not shown) is also provided on the surface opposite to the corresponding first waveguide transmission structure 1 and the second waveguide transmission structure 2, and the waveguide ridge on the first waveguide transmission structure 1 and the waveguide ridge 6 in the groove 8 are not electrically connected. In addition, the working principle of this third embodiment is the same as that of the first and second embodiments. When there is no gap between the first waveguide transmission structure 1 and the second waveguide transmission structure 2, it can be considered as a conventional double-ridge rectangular waveguide; and when there is a gap between the first waveguide transmission structure 1 and the second waveguide transmission structure 2, the artificial surface plasmon is excited at this time, which will bind the electromagnetic energy around the corrugated groove and propagate along the desired electromagnetic transmission direction.

[0083] Fig. 9 and Fig.10 1 is a schematic diagram of the front and back of the fourth embodiment of the present invention. Compared with the first three embodiments, the fourth embodiment connects a vertical waveguide 14 at the beginning of the gap waveguide transmission device and a vertical waveguide 15 at the end. In order to achieve impedance matching, a matching branch 12 is provided at the junction of the groove 8 and the vertical waveguide 14, and a matching branch 13 is provided at the junction of the groove 8 and the vertical waveguide 15. In order to prevent the existence of a gap between the first waveguide transmission structure 1 and the second waveguide transmission structure 2 during product assembly, this embodiment will set a periodic or quasi-periodic corrugated groove on the outer side of the side walls 91 and 92 of the groove 8. In this way, when there is a gap between the first waveguide transmission structure 1 and the second waveguide transmission structure 2, the corrugated groove realizes the function of artificial surface plasmon, binds electromagnetic energy, and makes the electromagnetic energy propagate in the desired direction.

[0084] In another embodiment, the waveguide transmission structure can be made of metal or other conductive materials, or it can be other materials and metallized on the surface to form a conductive layer. The present invention does not limit the thickness of the surface conductive layer or metal layer, as long as it includes a metal layer used for waveguide transmission, it is within the protection scope of the present invention.

[0085] As the most basic device of microwave circuit, transmission line is indispensable in microwave / millimeter wave applications. However, with the increasing requirements for the functional diversity of modern information technology, the shortcomings of traditional microstrip lines and coplanar waveguides in electromagnetic modes and performance are becoming increasingly prominent. In order to solve this problem, artificial surface plasmon transmission lines have been designed based on microstrip lines, but they are usually based on microstrip lines on printed circuit boards (PCBs). With the increase of application frequency, the dielectric loss of this microstrip line will become larger and larger with the increase of frequency, and for multi-channel transmission lines, its layout will also be limited by the design on the same plane. Therefore, with the increase of operating frequency, air waveguide transmission lines have become a hot application. It can not only solve the problem of loss well, but also can be applied to multi-channel design. However, traditional air waveguide transmission lines will have difficulties in assembly process, because in the high frequency band, once there is a gap between traditional air waveguide transmission lines, electromagnetic energy will leak, thereby affecting the transmission quality of the signal. Therefore, in view of the above problems, this paper proposes a waveguide transmission device based on artificial surface plasmon designed based on air waveguide. Its working principle is: by loading a periodic or non-periodic corrugated groove structure on the outside of the two narrow walls or two wide sides of the traditional air waveguide, when there is a gap between the first waveguide transmission structure and the second waveguide transmission structure, the existing corrugated groove can tightly bind the electromagnetic energy in the air waveguide transmission channel, thereby greatly reducing the difficulty of the assembly process while ensuring performance.

[0086] According to the working frequency requirements, the relevant dimensions of the corrugated grooves of the artificial surface plasmon can be calculated according to the following theory. Assuming that an infinitely long ideal metal conductor is simulated in the lateral direction of the transmission line, and its boundary conditions in the ±y direction are set to ideal magnetic walls, the model of this transmission channel can be equivalent to a layer of dielectric plate located above the ideal conductor with a thickness of h, which is uniform but anisotropic, such as Figure 5 , its related parameters:

[0087]

[0088] When electromagnetic waves propagate in the y or z direction at the speed of light, the following relationship can be obtained.

[0089]

[0090] The above relationship can be used to obtain the dispersion curve of the ideal metal structure SSPP transmission line unit, thereby obtaining the required corrugated groove related parameters, such as the width d of the corrugated groove, the depth h of the corrugated groove and the spacing p between adjacent corrugated grooves.

[0091] In the above formula, ε x , ε y , ε zis the relative dielectric constant of the anisotropic medium in the x, y, and z directions, μ y and μ z k is the magnetic permeability in the y and z directions of the anisotropic medium plate. x is the wave number of the anisotropic medium plate in one cycle in the x direction, k 0 is the number of waves in one period in free space.

[0092] When there is a gap between the first waveguide transmission structure and the second waveguide transmission structure, metal surface plasmons will be excited at the interface between the metal and the medium. This surface wave will reduce the transmission energy of electromagnetic energy in the desired direction, and the present invention simulates and regulates the characteristics of this surface wave by arranging periodic or non-periodic artificial structures, i.e., corrugated grooves, on the outer sides of the two side walls of the groove.

[0093] When electromagnetic waves are irradiated onto the artificial periodic structure, due to the periodicity and specific geometric shape of the structure, local enhancement and resonance effects of the electromagnetic field will be caused. This resonance causes the electromagnetic field to interact with the artificial structure, thereby exciting artificial surface plasmons. Further, the leaked electromagnetic waves are rapidly attenuated along the n direction and transmitted along the t direction (i.e., the desired electromagnetic transmission direction), so that when there is a gap between the first waveguide transmission structure and the second waveguide transmission structure, the artificial periodic structure can confine the electromagnetic energy in the transmission channel and allow the electromagnetic waves to be transmitted losslessly along the desired direction.

[0094] The parameter design method of the corrugated groove has been given above. The theoretical parameters are derived according to the actual working frequency, and then optimized in combination with electromagnetic simulation software to obtain the optimal size and minimum transmission loss.

[0095] In one embodiment, the other end of the vertical waveguide 14 is a first waveguide port 16, and the other end of the vertical waveguide 15 is a second waveguide port 17. In order to prevent energy leakage caused by a gap between the waveguide transmission device and other structures, as shown in FIG. Fig.10 As shown, in the fourth embodiment, periodic or quasi-periodic corrugated grooves are arranged around the first waveguide opening 16 and the second waveguide opening 17, and their function is also to prevent energy leakage caused by the gap.

[0096] Fig.11It is the simulated insertion loss curve of the fourth embodiment of the present invention. It can be seen from the figure that when there is no gap between the first waveguide transmission structure 1 and the second waveguide transmission structure 2, within the working frequency band, all embodiments of the present invention are designed with 76-81GHz as reference, and the insertion loss is 0.095dB / 25mm. When there is a gap between the first waveguide transmission structure 1 and the second waveguide transmission structure 2, and an artificial surface plasmon structure is arranged around the gap waveguide transmission device, the insertion loss within the working frequency band is 0.115dB / 25mm. When there is no artificial surface plasmon structure around the gap waveguide transmission device, and there is a gap between the first waveguide transmission structure 1 and the second waveguide transmission structure 2, the insertion loss within the working frequency band is 1dB / 25mm. It can be concluded that the design of artificial surface plasmon can greatly improve the electromagnetic energy leakage problem caused by the gap between the first waveguide transmission structure 1 and the second waveguide transmission structure 2.

[0097] Fig.12 It is a structural schematic diagram of embodiment 5 of the present invention. In this embodiment, the side wall 1 91 of the waveguide channel and the side wall 2 92 of the waveguide channel are the wide sides of the gap waveguide transmission device, and the depth of the metal groove is greater than the width. This is different from the first four embodiments. In the first four embodiments, the side wall 1 91 of the waveguide channel and the side wall 2 92 of the waveguide channel are the narrow sides of the gap waveguide transmission device. Fig.12 A cross-sectional schematic diagram of the fifth embodiment is given, and the current distribution at the waveguide port is illustrated. Fig.13 The situation in which a gap exists between the first waveguide transmission structure 1 and the second waveguide transmission structure 2 in the fifth embodiment is given, and the current distribution at the waveguide port is also given.

[0098] In the fifth embodiment, an artificial surface plasmon structure is also arranged on the outer side of the side wall of the waveguide channel, the purpose of which is to prevent the leakage of electromagnetic energy caused by the gap between the first waveguide transmission structure 1 and the second waveguide transmission structure 2, and to transmit the electromagnetic energy along the desired transmission path.

[0099] Fig.15The insertion loss of the gap waveguide transmission device of the scheme of the fifth embodiment is given. It can be seen from the figure that when there is no gap between the first waveguide transmission structure 1 and the second waveguide transmission structure 2, within the working frequency band, all embodiments of the present invention are designed with 76-81GHz as reference, and the insertion loss is 0.08dB / 25mm. When there is a gap between the first waveguide transmission structure 1 and the second waveguide transmission structure 2, and an artificial surface plasmon structure is arranged around the gap waveguide transmission device, the insertion loss within the working frequency band is 0.10dB / 25mm. When there is no artificial surface plasmon structure around the gap waveguide transmission device, and there is a gap between the first waveguide transmission structure 1 and the second waveguide transmission structure 2, the insertion loss within the working frequency band is 1dB / 25mm. It can be concluded that the design of artificial surface plasmon can greatly improve the electromagnetic energy leakage problem caused by the gap between the first waveguide transmission structure 1 and the second waveguide transmission structure 2.

[0100] The present invention also provides a method for manufacturing a gap waveguide transmission device, comprising:

[0101] Two transmission structures are provided, wherein a surface of at least one waveguide transmission structure opposite to the other waveguide transmission structure is provided with a groove, and a conductive layer is provided on the opposite surfaces of the two transmission structures, and the conductive layer covers the groove;

[0102] A corrugated groove is formed on the outer wall of the groove, and the corrugated groove is fixedly electrically connected to the conductive layer of at least one of the two waveguide transmission structures; the two waveguide transmission structures are installed so that the conductive layer covering the groove and the conductive layer of the other waveguide transmission structure form a strip-shaped waveguide transmission channel. In all the above embodiments, the periodic or quasi-periodic corrugated grooves can be manufactured by milling or etching. The first waveguide transmission structure 1 that does not contain a periodic or quasi-periodic metal layer can be stamped from brass, CNC-made or gold-plated on the plastic surface. The second waveguide transmission structure 2 can be realized by CNC or plastic electroplating.

[0103] The corrugated grooves of the waveguide device of the present invention, whose two side walls are electrically connected outside, can prevent the propagation of waves in the working frequency band in directions other than along the intended waveguide path.

[0104] The periodic or quasi-periodic corrugated grooves can be manufactured by milling, etching, injection molding followed by gold plating or other micro-molding techniques.

[0105] The metal layer which does not contain periodic or quasi-periodic corrugated grooves can be made by brass stamping, CNC manufacturing, gold plating on the surface after plastic injection molding, PCB sheet surface metal or other materials with good conductive properties.

[0106] The plated metal may be part or all of the metal layer, and the plated metal is generally copper, silver, gold or other metals.

[0107] The two waveguide transmission structures can realize gapless electrical connection between two metal layers by screwing, welding or riveting, or can realize gapless non-electrical connection between two waveguide transmission structures by screwing, welding or riveting.

[0108] The metal layer including the periodic or quasi-periodic corrugated grooves can be manufactured by CNC, PCB surface metal, electroplating after injection molding or other materials with good conductive properties.

[0109] The present invention etches periodic or quasi-periodic corrugated grooves on one side of the two side walls of the conventional rectangular waveguide away from the waveguide channel, and designs reasonable corrugated grooves according to the operating frequency. When there is a gap between the first waveguide transmission structure and the second waveguide transmission structure, the electromagnetic energy can be bound around the corrugated groove, and the electromagnetic energy is rapidly attenuated in a direction perpendicular to the desired transmission direction, thereby ensuring that the electromagnetic energy can be completely transmitted along the desired direction. We call this technology artificial surface plasmon. The application of this technology, first, it supports conventional welding processes, but does not require high precision like conventional welding processes. The technology of the present invention does not require strict welding process precision, and can ensure good electrical performance at the same time; secondly, the technology of the present invention can also be welded-free, and can be directly assembled by screwing, riveting or other fixing methods, and can also ensure good electrical performance. The invention of this new technology can greatly increase the assembly tolerance redundancy of the product, thereby improving the assembly yield of the production line, greatly reducing the price cost, and has very excellent electrical performance, so it is very suitable for millimeter wave frequency applications.

[0110] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A gap waveguide transmission device based on artificial surface plasmon, characterized in that: include: Two waveguide transmission structures are arranged opposite to each other, and the two waveguide transmission structures form a transmission channel. The connecting surfaces of the two waveguide transmission structures have a gap, and the inner wall of the transmission channel has a conductive layer. The outer periphery of the side wall of the transmission channel with the gap is provided with a corrugated groove, and the side of the corrugated groove facing the outer side of the side wall has protrusions and grooves arranged at periodic or quasi-periodic intervals, and the surfaces of the protrusions and grooves of the corrugated groove have a conductive layer, and the conductive layer is electrically connected to the conductive layer of the inner wall of the transmission channel.

2. The gap waveguide transmission device according to claim 1, characterized in that: The grooves and protrusions of the corrugated grooves have the same width and interval, and the conductive layer on the surface of the corrugated grooves is a metal layer.

3. The gap waveguide transmission device according to claim 1, characterized in that: One of the waveguide transmission structures is provided with a groove constituting a waveguide transmission channel, and the surface of the other waveguide transmission structure opposite to the groove is a smooth surface without any protrusions.

4. The gap waveguide transmission device according to claim 1, characterized in that: The conductive layer arranged on the waveguide transmission structure is a metal layer.

5. The gap waveguide transmission device according to claim 1, characterized in that: The two waveguide transmission structures are both provided with corresponding grooves, and the corresponding grooves of the two waveguide transmission structures constitute a waveguide transmission channel.

6. The gap waveguide transmission device according to claim 1, characterized in that: The concave-convex direction of the corrugated groove is perpendicular to the groove side wall of the waveguide transmission channel.

7. The gap waveguide transmission device according to claim 3 or 5, characterized in that: The corrugated groove is electrically connected to the conductive layer of the side wall of the waveguide transmission channel, and the height of the corrugated groove and the groove side wall in the same direction is the same as the height of the groove side wall.

8. The gap waveguide transmission device according to claim 6, characterized in that: The width of the side wall of the groove along the direction perpendicular to the waveguide transmission channel ranges from 0.1mm to 5mm, the height ranges from 0.1mm to 5mm, the depth of the corrugated groove is set in the range of 0.1mm to 2mm; the width of the corrugated groove is set in the range of 0.1mm to 2mm; the width of the raised part in the middle of adjacent corrugated grooves is set in the range of 0.1mm to 2mm; the height of the corrugated groove is between 0.1mm and 5mm.

9. The gap waveguide transmission device according to claim 1, characterized in that: A conductor device is also arranged in the groove, and the conductor device is fixedly and electrically connected to the conductive layer of at least one of the two waveguide transmission structures, and the conductor device is used to form the waveguide transmission path.

10. The gap waveguide transmission device according to claim 8, characterized in that: The conductor device is a single waveguide ridge or a double waveguide ridge. One end of the waveguide ridge is used to connect to the matching transition of the integrated circuit module, and the other end is also used to connect to the matching transition of the integrated circuit module.

11. The gap waveguide transmission device according to claim 9, characterized in that: The conductor component includes two conductor components which are opposite to each other and are respectively connected to the conductive layers of two waveguide transmission structures, and the two conductor components are in non-electrical connection.

12. The gap waveguide transmission device according to claim 9, characterized in that: The conductor device is fixedly connected to the bottom surface of the groove and is located at the center of the bottom surface of the groove, and is symmetrically distributed along the center line in the transmission direction, or the conductor device is fixedly connected to a waveguide transmission structure without a groove, and is projected along a direction perpendicular to the bottom surface of the groove, and the conductor device is located in the middle of the bottom surface of the groove.

13. The gap waveguide transmission device according to claim 1, characterized in that: At least one of the two waveguide transmission structures is also provided with a protruding metal structure having the same height as the side wall of the groove, and the protruding metal structure is provided with screw holes having the same number as the screw holes on the other metal layer.

14. The gap waveguide transmission device according to claim 1, characterized in that: The waveguide transmission structure and the conductive layer are an integrated metal structure, and the corrugated groove and the conductive layer on its surface are an integral metal structure.

15. The gap waveguide transmission device according to claim 9, characterized in that: The conductor device is a rectangular waveguide ridge, and the waveguide ridge is straight, curved or stepped.

16. The gap waveguide transmission device according to claim 1, characterized in that: The corrugated grooves located on two opposite side walls of the groove are in electrical connection through the side walls of the groove and the conductive layer of one of the two waveguide transmission structures.

17. The gap waveguide transmission device according to claim 1, characterized in that: One of the two waveguide transmission structures is further provided with at least one waveguide opening, and the waveguide opening is used for transmitting radiation to the waveguide transmission line and receiving radiation from the waveguide transmission line.

18. The gap waveguide transmission device according to claim 1, characterized in that: The shapes of the protrusions and grooves of the corrugated grooves are any of rectangle, triangle, semicircle, trapezoid and ellipse.

19. A method for manufacturing a gap waveguide transmission device based on artificial surface plasmon according to any one of claims 1 to 16, comprising: Two transmission structures are provided, wherein a surface of at least one waveguide transmission structure opposite to the other waveguide transmission structure is provided with a groove, and a conductive layer is provided on the opposite surfaces of the two transmission structures, and the conductive layer covers the groove; A corrugated groove is formed on the outer wall of the groove, and the corrugated groove is fixedly electrically connected to the conductive layer of at least one of the two waveguide transmission structures; the two waveguide transmission structures are installed so that the conductive layer covering the groove and the conductive layer of the other waveguide transmission structure form a strip-shaped waveguide transmission channel.

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