A flange and terahertz waveguide connector based on electromagnetic bandgap structure

Abstract

The present invention provides a flange based on an electromagnetic bandgap structure and a terahertz waveguide connector, wherein the flange based on the electromagnetic bandgap structure comprises: a metal plate, a waveguide opening is opened in the middle of the metal plate, a periodic square column electromagnetic bandgap structure is etched on the metal plate, the square column electromagnetic bandgap structure protrudes from the surface of the metal plate, and an elliptical impedance transformation transition structure is arranged near the waveguide opening; when docking, the waveguide opening of the planar flange is aligned with the waveguide opening of the flange based on the electromagnetic bandgap structure, and the square column electromagnetic bandgap structure faces the planar flange; there is a flange docking air gap between the planar flange and the flange based on the electromagnetic bandgap structure, the energy in the waveguide propagates in a vertical direction, and the electromagnetic leakage along the gap is suppressed in the periodic square column electromagnetic bandgap structure.

Description

Technical Field

[0001] The invention belongs to the field of terahertz waveguides, and in particular relates to a flange based on an electromagnetic bandgap structure and a terahertz waveguide connector. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] Terahertz testing often uses a waveguide interface, which uses a standard flange for tight connection. Fixing screws are required to eliminate air gaps between the flange surfaces to ensure high transmission efficiency and good standing wave characteristics. When testing the DUT, the screws need to be removed multiple times to ensure ideal docking of the waveguide port, which reduces test efficiency and greatly affects the user experience.

[0004] When the terahertz waveguide port is connected, the waveguide flange has relatively high requirements for tight connection. Due to the short wavelength of the high frequency band, there are high requirements for the precision of the connector structure, and the waveguide flange connection needs to be fixed manually. Often, gaps will remain between the waveguide ports due to loose fixation, causing electromagnetic leakage, increasing transmission loss, and affecting the integrity of signal transmission. This phenomenon is particularly obvious in the terahertz high frequency band, which increases the test error while reducing the test efficiency, and cannot meet the requirements of high-precision and fast testing. Summary of the invention

[0005] In order to solve the above problems, the present invention proposes a flange and a terahertz waveguide connector based on an electromagnetic bandgap structure. The present invention adopts gap waveguide technology to improve the waveguide connection flange surface, eliminating the trouble of screw installation and only requiring pin positioning, which greatly improves the test efficiency.

[0006] According to some embodiments, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a flange based on an electromagnetic bandgap structure.

[0008] A flange based on an electromagnetic bandgap structure comprises: a metal plate, a waveguide opening is opened in the middle of the metal plate, a periodic square column electromagnetic bandgap structure is etched on the metal plate, the square column electromagnetic bandgap structure protrudes from the surface of the metal plate, and an elliptical impedance transformation transition structure is arranged near the waveguide opening;

[0009] During docking, the waveguide opening of the planar flange is aligned with the waveguide opening of the flange based on the electromagnetic band gap structure, and the square column electromagnetic band gap structure faces the planar flange; there is a flange docking air gap between the planar flange and the flange based on the electromagnetic band gap structure, the energy in the waveguide propagates in the vertical direction, and the electromagnetic leakage along the gap is suppressed in the periodic square column electromagnetic band gap structure.

[0010] In a second aspect, the present invention provides a terahertz waveguide connector based on an electromagnetic bandgap structure.

[0011] A terahertz waveguide connector based on an electromagnetic bandgap structure comprises: a first flange, a second flange and a straight-through section, wherein the first flange and the second flange are connected via the straight-through section, and the first flange and the second flange are both provided with the flange based on the electromagnetic bandgap structure described in the first aspect.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] The terahertz waveguide connector based on the electromagnetic band gap structure proposed in the present invention can be connected to a traditional standard flange as a waveguide connector. It only needs pins to align and no screws are required to tighten. A certain air gap is allowed between the flange surfaces, ensuring high-quality signal transmission while achieving rapid testing.

[0014] Compared with the prior art, the present invention uses an electromagnetic band gap structure to replace the metal surface near the waveguide port. The prior art uses an electromagnetic band gap structure to replace the waveguide side wall. Although both use the electromagnetic wave suppression function of the electromagnetic band gap, the design principles are different.

[0015] The present invention realizes high-quality transmission of waveguide signals in the case of gap docking.

[0016] The present invention makes up for the rapid connection function of the waveguide device which is not solved in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0018] Figure 1 is a dispersion curve diagram of an electromagnetic bandgap structure shown in the first embodiment of the present invention;

[0019] Figure 2 is a flange structure diagram based on an electromagnetic bandgap periodic structure shown in the first embodiment of the present invention;

[0020] Figure 3 is a simulation diagram of flange transmission performance based on an electromagnetic bandgap periodic structure shown in the first embodiment of the present invention;

[0021] Figure 4 is a comparison diagram of the gap field distribution between the new flange and the traditional flange shown in the second embodiment of the present invention;

[0022] FIG5( a ) is an overall structural diagram of a terahertz waveguide connector based on an electromagnetic bandgap structure shown in Embodiment 2 of the present invention;

[0023] FIG5( b ) is a top view of a terahertz waveguide connector based on an electromagnetic bandgap structure according to a second embodiment of the present invention;

[0024] FIG6( a ) is a structural diagram of a flange surface for use in a frequency band below 250 GHz, shown in Embodiment 2 of the present invention;

[0025] FIG6( b ) is a structural diagram of a flange surface for use in a frequency band above 250 GHz, shown in Embodiment 2 of the present invention;

[0026] Among them, 1. periodic square column electromagnetic band gap structure, 2. elliptical impedance transformation transition structure, 3. flange docking air gap, 4. first flange plate, 5. second flange plate, 6. pin, 7. first connecting hole, 8. second connecting hole, 9. straight-through section, 10. annular protective surface, 11. flange based on electromagnetic band gap structure. DETAILED DESCRIPTION

[0027] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0028] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0029] In the present invention, the directions or positional relationships indicated by terms such as "upper" and "lower" are based on the directions or positional relationships shown in the accompanying drawings. They are relational words determined only for the convenience of describing the structural relationships of the various parts or elements of the present invention. They do not specifically refer to any part or element in the present invention and should not be understood as limitations on the present invention.

[0030] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0031] In the present invention, terms such as "connection" should be understood in a broad sense, indicating that it can be fixedly connected, integrally connected or detachably connected; it can be directly connected or indirectly connected through an intermediate medium. For relevant scientific research or technical personnel in this field, the specific meaning of the above terms in the present invention can be determined according to specific circumstances, and it cannot be understood as a limitation of the present invention.

[0032] Embodiment 1

[0033] This embodiment provides a flange based on an electromagnetic band gap structure.

[0034] A flange based on an electromagnetic bandgap structure comprises: a metal plate, a waveguide opening is opened in the middle of the metal plate, a periodic square column electromagnetic bandgap structure 1 is etched on the metal plate, the square column electromagnetic bandgap structure protrudes from the surface of the metal plate, and an elliptical impedance transformation transition structure 2 is arranged near the waveguide opening;

[0035] During docking, the waveguide opening of the planar flange is aligned with the waveguide opening of the flange 11 based on the electromagnetic band gap structure, and the square column electromagnetic band gap structure faces the planar flange; there is a flange docking air gap 3 between the planar flange and the flange 11 based on the electromagnetic band gap structure, the energy in the waveguide propagates in the vertical direction, and the electromagnetic leakage along the gap is suppressed in the periodic square column electromagnetic band gap structure 1.

[0036] Taking the 325-500GHz frequency band as an example, the dispersion curve of the electromagnetic bandgap structure is designed as follows: Figure 1 As shown. Selecting the side length, height and period distance parameters of the periodic square column can adjust the corresponding electromagnetic bandgap frequency and bandwidth. Simulate four working modes and count the mode distribution above 50GHz. There is no mode distribution in the 325-500GHz band. At this time, the periodic structure presents a bandgap characteristic, that is, electromagnetic waves are not allowed to propagate.

[0037] Flange design based on electromagnetic bandgap periodic structure Figure 2 As shown. Two layers of metal plates with a certain thickness are stacked, a waveguide opening is opened in the middle of the metal plate, and the waveguide openings of the upper and lower metal plates are aligned. The traditional flange is a metal plane, and the new flange designed in this embodiment improves one side of the metal plate, that is, a periodic square column electromagnetic band gap structure 1 is etched on a single-side metal surface, the square column protrudes from the metal surface, and there is a stepped elliptical impedance transformation transition structure near the waveguide opening. When the traditional flange plane is connected to the new flange surface designed in this embodiment, there is a flange connection air gap 3, the energy in the waveguide propagates in the vertical direction, and the electromagnetic leakage along the gap is suppressed in the periodic structure.

[0038] The transmission performance of flange waveguide based on electromagnetic bandgap periodic structure in the 325-500GHz frequency band is as follows Figure 3 As shown. The optimized periodic structure makes the bandgap bandwidth cover 325-500GHz, and the gap width is selected as 50μm to simulate the transmission characteristics and standing wave characteristics of the waveguide port. When the traditional flange, i.e., the plane metal, is used, the transmission coefficient performance is significantly reduced due to the leakage of the gap. The flange with electromagnetic bandgap periodic structure is used to replace a metal plane, and the PEC-PMC is equivalently constructed. At this time, the transmission coefficient remains at about 0dB, and the transmission performance is excellent. In addition, the port standing wave coefficient is below -20dB, and the performance indicators meet the general device connection needs. Figure 4The electric field distribution in the air gap is compared between the new flange designed for this embodiment and the traditional flange when the simulated signal is transmitted along the waveguide. It can be seen that the traditional flange on the left has serious leakage along the gap, while the new flange on the right has a good suppression of the leakage field along the gap due to the periodic surface, so that the energy is concentrated near the waveguide mouth, ensuring the transmission quality of the longitudinal signal. This simulation verifies the effectiveness of the new flange based on the electromagnetic bandgap periodic structure for contactless connection.

[0039] As one or more implementation modes, the elliptical impedance transformation transition structure 2 is a stepped elliptical impedance transformation transition structure, which includes an inner circle elliptical impedance transformation transition structure and an outer circle elliptical impedance transformation transition structure, and the surface of the inner circle elliptical impedance transformation transition structure is higher than the surface of the outer circle elliptical impedance transformation transition structure.

[0040] As one or more implementation modes, the upper surfaces of all the periodic square column electromagnetic bandgap structures 1 are on the same horizontal plane.

[0041] The waveguide flange structure based on the electromagnetic bandgap structure described in this embodiment has periodic square columns arranged near the waveguide port, and the impedance matching transition between the waveguide port and the square columns is achieved through an ellipse or a stepped ellipse. An electromagnetic bandgap structure is added to the waveguide flange surface, and terahertz waveguide connectors such as straight waveguides and curved waveguides are designed based on this structure. The periodic square columns are located on a circular base, and the height of the base is adjusted so that the upper surfaces of the various structural metals on the flange surface are located on the same horizontal plane. In the terahertz high-frequency band, an annular protective surface is added to the periphery of the periodic square columns, and the upper surface of the periodic square columns and the upper surface of the protective surface are located on the same horizontal plane to protect the square columns from damage by external forces.

[0042] Embodiment 2

[0043] This embodiment provides a terahertz waveguide connector based on an electromagnetic bandgap structure.

[0044] As introduced in the background technology, terahertz test and measurement instruments based on traditional waveguide connectors need to repeatedly remove screws when testing the test piece, which has a long test cycle and cannot meet the needs of rapid testing. In addition, errors are introduced due to different installation tightness during each connection, resulting in unstable testing, which is more obvious in the high frequency band.

[0045] To this end, this embodiment provides a terahertz waveguide connector based on an electromagnetic band gap structure, including: a first flange 4, a second flange 5 and a straight-through section 9, the first flange 4 and the second flange 5 are connected through the straight-through section 9, and the first flange 4 and the second flange 5 are both provided with a flange 11 based on the electromagnetic band gap structure described in Example 1.

[0046] This embodiment proposes a terahertz waveguide connector based on gap waveguide technology, with a frequency coverage of 60-500GHz, covering multiple standard waveguide frequency bands such as 60-90 / 90-140 / 140-220 / 220-325 / 325-500 and 75-110 / 110-170 / 170-260 / 260-400. Two structural schemes are adopted according to the characteristics of flange surfaces in different frequency bands. The electromagnetic band gap periodic structure is used to replace the metal surface of the waveguide flange to suppress the lateral leakage of electromagnetic waves along the flange surface, thereby allowing a certain air gap to exist when the waveguide flange is connected.

[0047] The principle of electromagnetic bandgap periodic structure suppressing electromagnetic leakage along the gap is as follows. When two infinitely large PEC surfaces are placed in parallel with a spacing of 2d, the PEC-PEC structure has no bandgap characteristics for vertically polarized electric fields and exhibits all-pass characteristics, while it exhibits high-pass filtering characteristics when the electric field is horizontally polarized. The periodic surface can be replaced by a PMC equivalent to replace one of the PECs. The PEC-PMC structure suppresses the vertically polarized electric field and exhibits high-pass characteristics for the horizontally polarized electric field. Therefore, the PEC-PMC structure can achieve the function of electromagnetic wave suppression.

[0048] Based on the electromagnetic bandgap structure, a series of terahertz waveguide connectors with a frequency coverage of 60-500GHz and multiple standard waveguide frequency bands are designed to meet daily testing needs. The overall structure of the terahertz waveguide connector based on the electromagnetic bandgap structure is shown in Figures 5(a) and 5(b). Figure 5(a) is the overall structure, and Figure 5(b) is a top view. The bottom view is the same as the top view. It includes two flanges 1 and a straight-through section 9, which have the same appearance as a general straight-through waveguide. The pin 6 and the first connecting hole 7 and the second connecting hole 8 are used for positioning. The flange surface joint includes an annular protective surface 10, and an electromagnetic bandgap periodic surface 6 is etched near the waveguide mouth.

[0049] 60-500GHz is divided according to the standard waveguide frequency band. The frequency bands below 250GHz and 90-140 / 110-170 / 140-220GHz do not include the annular protection surface 10. The periodic square column is directly used as the force-bearing surface. The periodic square column is located on the circular base so that the upper surface is located on the same horizontal plane, as shown in Figure 6(a). This design can make use of the flange joint surface to manufacture more periodic structures as much as possible to ensure the electromagnetic suppression capability.

[0050] In the frequency bands above 250 GHz and 270-260 / 220-325 / 260-400 / 325-500 GHz, the square pillars are easily damaged by external forces due to their small size. Therefore, an annular protective surface 10 is added to the periphery of the periodic square pillars, and the surface of the protective surface is located at the same horizontal plane as the upper surface of the square pillars, as shown in FIG6( b ).

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A flange based on an electromagnetic band gap structure, characterized in that: It comprises: a metal plate, a waveguide opening is opened in the middle of the metal plate, a periodic square column electromagnetic bandgap structure is etched on the metal plate, the square column electromagnetic bandgap structure protrudes from the surface of the metal plate, and an elliptical impedance transformation transition structure is arranged near the waveguide opening; During docking, the waveguide opening of the planar flange is aligned with the waveguide opening of the flange based on the electromagnetic bandgap structure, and the square column electromagnetic bandgap structure faces the planar flange; there is an air gap between the planar flange and the flange based on the electromagnetic bandgap structure, the energy in the waveguide propagates in the vertical direction, and the electromagnetic leakage along the gap is suppressed in the periodic square column electromagnetic bandgap structure; Periodic square columns are arranged near the waveguide opening, and the metal surface of the waveguide flange is replaced by an electromagnetic bandgap periodic structure, and an impedance matching transition is achieved between the waveguide opening and the square columns through an ellipse or a stepped ellipse; When the waveguide frequency band is higher than 250 GHz and lower than 500 GHz, an annular protective surface is provided on the periphery of the periodic square column electromagnetic bandgap structure of the flange; The upper surfaces of all the periodic square column electromagnetic band gap structures are on the same horizontal plane.

2. The flange based on the electromagnetic band gap structure according to claim 1, characterized in that: The elliptical impedance transformation transition structure is a stepped elliptical impedance transformation transition structure.

3. The flange based on the electromagnetic band gap structure according to claim 2, characterized in that: The stepped elliptical impedance transformation transition structure comprises an inner circle elliptical impedance transformation transition structure and an outer circle elliptical impedance transformation transition structure, and the surface of the inner circle elliptical impedance transformation transition structure is higher than the surface of the outer circle elliptical impedance transformation transition structure.

4. A terahertz waveguide connector based on an electromagnetic bandgap structure, characterized in that: include: A first flange, a second flange and a straight-through section, wherein the first flange and the second flange are connected via the straight-through section, and the first flange and the second flange are both provided with a flange based on an electromagnetic band gap structure as described in any one of claims 1-3.

5. The terahertz waveguide connector based on the electromagnetic bandgap structure according to claim 4, characterized in that: The first flange and the second flange are both provided with connecting holes and pins.

6. The terahertz waveguide connector based on the electromagnetic bandgap structure according to claim 5, characterized in that: The connection hole includes a first connection hole and a second connection hole.

7. The terahertz waveguide connector based on the electromagnetic bandgap structure according to claim 6, characterized in that: A connecting pin is inserted into the first connecting hole.

8. The terahertz waveguide connector based on the electromagnetic bandgap structure according to claim 4, characterized in that: The annular protection surface is on the same horizontal plane as the upper surface of the periodic square column electromagnetic band gap structure.

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