A millimeter-wave filtering jumper based on a single-slot gap waveguide cavity

Abstract

A millimeter-wave filtering jumper based on a single-slot gap waveguide cavity according to the present invention belongs to the field of microwave technology. The gap waveguide jumper includes: a device metal body, a central slot, four resonant irises, and a cover plate. Among them, the device metal body is provided with four waveguide ports; the central slot is arranged in the device metal body; the four resonant irises are arranged in the device metal body, one end of which is connected to the waveguide ports in one-to-one correspondence, and the other end is connected to the central slot. The cover plate is arranged on the device metal body, and the periodic metal pins on the cover plate form a non-contact electromagnetic bandgap structure to form a stopband. In addition, the groove on the cover plate and the central slot of the device metal body form a resonant cavity. The gap waveguide jumper provided by the embodiment of the present application has the advantages of miniaturization, high frequency selectivity, and high isolation, and can be better applied to the field of wireless communication systems.

Description

Technical Field

[0001] The present invention relates to the technical field of communication antennas, and specifically to a millimeter-wave filtering jumper based on a single-slot gap waveguide cavity. Background Art

[0002] As traditional wireless spectrum resources become increasingly saturated, the millimeter-wave band has become one of the most promising candidate bands for 5G and the upcoming 6G wireless communications. Bandpass filters are usually used in wireless communication systems to suppress unwanted signals, while frequency dividers are usually used in multi-beam multiple-input multiple-output antenna systems and high-density packaged integrated circuits to prevent interference between two or more cross-signal transmission paths. Usually, these two different types of devices are used in a cascaded manner, which inevitably increases the overall complexity of the system.

[0003] In this context, researchers have proposed various filtering jumper schemes based on planar structures. Although such structures have the advantages of easy processing and integration, at millimeter-wave frequencies, their insertion losses are relatively high, making it difficult to meet the requirements of high-performance communication systems. In recent years, slot gap waveguide, as a new type of low-loss transmission line structure, has gradually become a research hotspot in the design of millimeter-wave devices. As a type of gap waveguide, slot gap waveguide effectively reduces the radiation loss and transmission loss of electromagnetic waves, while maintaining good electromagnetic shielding characteristics. This structure provides a new technical path for the design of millimeter-wave filtering jumpers. However, there are still bottlenecks in the existing research on using slot gap waveguide to realize filtering jumpers. For example, how to achieve high selectivity in the high-frequency band and the comprehensive optimization of structural compactness are still problems that need to be solved urgently.

[0004] Compared with the prior art, the technical differences are as follows:

[0005] Comparison with the technology of the published patent CN115693064A "A filtering jumper based on a hemispherical resonator";

[0006] 1. CN115693064A adopts a filtering jumper structure based on a hemispherical resonator, including five hemispherical resonators. With the second hemispherical resonator as the center, it is integrally formed and connected to the other four resonators through notch coupling. In this study, a single-slot gap waveguide structure is adopted, including a device metal body, a central slot, four resonant irises, and a cover plate. The periodic metal pins on the cover plate form a non-contact electromagnetic bandgap structure to form a stopband. Compared with CN115693064A, the single-slot gap waveguide structure adopted in this study is easier to miniaturize and integrate, meeting the requirements of modern wireless communication systems for device size. In addition, the non-contact electromagnetic bandgap structure on the cover plate can effectively avoid the problem of increased insertion loss due to imperfect contact between different metal layers in the millimeter-wave band, making it more suitable for operating in the millimeter-wave band.

[0007] Second, CN115693064A lacks the setting of transmission zeros, and the frequency selectivity of the device is limited to a certain extent. Transmission zeros play a key role in filter design. They can significantly suppress signal transmission at specific frequencies, thereby improving the frequency selectivity and stopband rejection ability of the filter. In this study, by means of cross-coupling and adding capacitive stubs, a transmission zero is generated in both the upper stopband and the lower stopband, increasing the frequency selectivity of the device and better meeting the requirements of future communication technologies for high-performance filters. Summary of the Invention

[0008] To solve the above problems, the present invention proposes a millimeter-wave filtering jumper based on a single-slot gap waveguide cavity to solve the problems of excessive loss, poor selectivity, and large size in the related technologies of filtering jumpers in the millimeter-wave band.

[0009] To achieve the above object, the technical solution adopted by the present invention is:

[0010] A millimeter-wave filtering jumper based on a single-slot gap waveguide cavity includes a device metal body, a central slot, four resonant irises, and a cover plate. The device metal body is provided with four waveguide interfaces. The central slot is arranged in the device metal body. The four resonant irises are arranged in the device metal body. One end of the resonant iris is connected to the waveguide interface in one-to-one correspondence, and the other end is connected to the central slot. The cover plate is covered on the device metal body. Metal pins are arranged in rows along the perimeter below the cover plate, and a central groove part is formed. There is an air gap between the lower end of the metal pin and the metal body to form a non-contact electromagnetic bandgap structure. The air gap is less than 1 / 4λ, where λ is the wavelength corresponding to the center frequency of the gap waveguide jumper. The central groove part formed below the cover plate and the central slot form a resonant cavity.

[0011] As a further improvement of the present invention, an L-shaped capacitive stub is provided on the waveguide interface of the device metal body near the resonant iris.

[0012] As a further improvement of the present invention, support columns are provided at the four corners of the device metal body. The height of the support column is greater than the height of the metal pin. An internal threaded section is constructed inside the support column, and through holes are provided in the cover plate corresponding to the areas of the support columns.

[0013] As a further improvement of the present invention, the device metal body, central slot, four resonant irises, and cover plate of the millimeter-wave filtering jumper based on a single-slot gap waveguide cavity are made of a hybrid polyurethane acrylate resin material and electroplated with 10μm - 12μm of copper material.

[0014] As a further improvement of the present invention, the four waveguide interfaces include two input interfaces and two output interfaces and are symmetrically arranged.

[0015] The beneficial effects of the present invention are as follows:

[0016] The filtering jumper of the present invention exhibits low insertion loss in the millimeter-wave band. This characteristic significantly improves the signal transmission efficiency, is particularly suitable for high-speed communication systems, reduces signal attenuation, and ensures high-quality signal transmission.

[0017] The filtering jumper of the present invention realizes third-order filtering crossover by using a single generalized-connected gap waveguide resonator and combining a resonant diaphragm, and has a highly compact structure, making it easier to integrate into miniaturized electronic systems.

[0018] The filtering jumper of the present invention utilizes an exact degenerate mode to ensure excellent isolation performance. This high isolation performance effectively reduces signal interference, improves the overall stability and reliability of the system, and is particularly suitable for complex communication networks.

[0019] The filtering jumper of the present invention realizes a transmission zero in the upper stopband through cross-coupling and realizes a transmission zero in the lower stopband by adding a capacitive stub. The two transmission zeros provide high-frequency selectivity for the filtering jumper of the present invention. This design of dual transmission zeros significantly enhances the frequency selectivity of the filter, can more precisely separate the target frequency band, reduce signal crosstalk, and improve system performance. Brief Description of the Drawings

[0020] Figure 1 It is a schematic diagram of the overall structure of the filtering jumper in the embodiment of the present application;

[0021] Figure 2 is Figure 1 a perspective view of the device metal body of the filtering jumper in

[0022] Figure 3 is Figure 1 the cover plate of the filtering jumper in

[0023] Figure 4 is Figure 1 a perspective view of a partial structure of the filtering jumper in

[0024] Figure 5 is Figure 3 the top view in

[0025] Figure 6 is Figure 1 a schematic diagram of the capacitive stub provided on the metal body of the filtering jumper in

[0026] Figure 7 is the dispersion diagram of the metal pins with periodic boundaries;

[0027] Figure 8It is the scattering parameter diagram of the filter jumper;

[0028] The component names are as follows:

[0029] 100, device metal body; 101, waveguide interface; 102, L type capacitive stub; 103, support post; 200, central slot; 300, resonant iris; 400, cover plate; 401, metal pin. Specific embodiments

[0030] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments:

[0031] The gap waveguide is a new type of artificial electromagnetic material based on non-contact electromagnetic bandgap structure. Its core principle is to form an electromagnetic bandgap between parallel conductor plates through a periodic structure (such as a metal column array), thereby suppressing the propagation of electromagnetic waves in the parallel plate mode, while allowing waves to be transmitted in a low-loss manner along a specific path (such as a ridge, slot or microstrip line). In particular, the jumper manufactured under the guidance of the slot gap waveguide technology, compared with the traditional jumper, can not only be applied in the millimeter wave band, but also has the advantages of small insertion loss and high quality factor, etc., and is an ideal radio frequency front-end device.

[0032] However, in the related art, the jumper structure adopting the slot gap waveguide principle has a small number reported at present and relatively limited applications. It usually faces technical problems such as it is difficult to balance low insertion loss and small size, and the lack of transmission zeros, etc., and has relatively large application limitations.

[0033] Based on the above description, the gap waveguide filter jumper provided by the embodiments of the present application utilizes the first slot and four resonant diaphragms opened on the device body. The cover plate is arranged on the device body, and the groove in the middle of the cover plate and the first slot form a waveguide resonant cavity. The input signal enters the device body from the waveguide port, passes through the resonant diaphragm, propagates to the waveguide resonant cavity, and then enters the next resonant diaphragm, and finally is output from another waveguide port. Among them, the frequency of the input signal is filtered by using the waveguide resonant cavity and the resonant diaphragm to remove unnecessary frequency components, and the transmission and isolation of signals between channels are realized through this pair of degenerate modes of TE 201 and TE 102 Finally, the effects of filtering and avoiding interference between cross-signal transmission paths are achieved. By precisely controlling the size of the gap, the signal of a specific frequency is selectively adjusted, the filtering performance is optimized, the contact loss and electromagnetic leakage are reduced, and the reliable transmission of high-frequency signals is ensured.

[0034] The waveguide filter power divider of the embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0035] As Figure 1 As Figure 2 And asFigure 3 As shown in Figure 3 , the gap waveguide bridge of the embodiment of the present application includes a device metal body 100, a central slot 200 provided on the device metal body 100, and a cover plate 400 covering the device metal body 100. Among them, the device metal body 100 is provided with four waveguide interfaces 101 for input / output; the central slot 200 is provided on the device metal body 100, and the central slot 200 is connected to the four waveguide interfaces 101. The cover plate 400 covers the device metal body 100, and the groove in the middle of the cover plate 400 and the central slot 200 provided on the device metal body 100 are configured to form a waveguide resonant cavity with the central slot 200.

[0036] The cover plate 400 and the device metal body 100 together constitute a gap waveguide. Traditional waveguide bridges generally require complex metal contact components and alignment accuracy. However, the structure of the embodiment of the present application guides the transmission of electromagnetic waves in a non-contact manner, thereby effectively reducing electrical contact losses. Correspondingly, since complex alignment progress is not required, the manufacturing and assembly processes are also simplified, reducing the manufacturing cost.

[0037] The device of the embodiment of the present application can be prepared by stereolithography 3D printing technology. The device is made of a hybrid polyurethane acrylate resin material and electroplated with 10 μ m - 12 μ m of copper material. Exemplarily, after the device is printed and formed, it is electroplated with 10 μ m of copper layer.

[0038] Since the gap waveguide does not rely on the traditional transmission method of metal - contact waveguides, but guides electromagnetic waves through an accurate physical gap, that is, the core of the gap waveguide lies in precisely controlling the size and shape of the gap in the structure. Therefore, using stereolithography 3D printing technology can ensure that the size of the device meets the usage requirements, and electroplating copper material ensures that the metal surface is smooth with low electromagnetic wave reflection loss, thereby achieving good gap waveguide performance. As an alternative implementation, electroplated copper can also be replaced with other metal materials, such as silver, gold, or other conductive materials.

[0039] The four waveguide interfaces 101 provided on the device metal body 100 are used to receive external signals, introduce the signals into the gap waveguide filter bridge for processing, and the input waveguide is usually connected to a signal source (such as a microwave transmitter, a radio frequency signal generator, etc.). Of course, the above - mentioned connection and usage scenarios are only for illustrative purposes, and for different usage scenarios, the device ports actually connected to the device metal body 100 are also different.

[0040] The four waveguide interfaces 101 can be connected to external devices through standard waveguides, or through coaxial cables, or through bolts to the waveguide flanges of external devices. The embodiments of the present application do not make absolute limitations on this.

[0041] As Figure 2 and Figure 3 shown, in the embodiments of the present application, a plurality of metal pins 401 are arranged in an array on the side of the cover plate 400 facing the device metal body 100. When the cover plate 400 is buckled to the device metal body 100, there is an air gap between the metal pins 401 and the central slot 200. The metal pins 401 can be metal pins or other columnar structures. The groove structure in the middle of the cover plate 400, the gap formed between the metal pins 401 and the central slot 200, and the central slot 200 together form the aforementioned waveguide resonator.

[0042] It should be noted that the lengths of the metal pins 401 on the cover plate 400 are the same and evenly distributed, forming an electromagnetic bandgap structure (EBG), effectively suppressing electromagnetic leakage of non-waveguide paths, ensuring that waveguide signals only propagate along the central slot 200, and reducing radiation loss. The gaps between the metal pins 401 and the central slot 200 are kept consistent to prevent signal reflection, waveguide loss, or distortion caused by uneven gaps.

[0043] Here, the distance between the central slot 200 and the metal pins 401 is less than 1 / 4 λ , λ which is the wavelength corresponding to the center frequency of the filter jumper.

[0044] A plurality of support columns 103 are protrudingly formed on the device metal body 100. The support columns 103 are used to support the cover plate 400, and the height of the support columns 103 is greater than the height of the metal pins 401.

[0045] The support columns 103 are respectively arranged on the four peripheral edges of the device metal body 100. Internal threaded sections are formed in the support columns 103. Through holes are provided in the area of the cover plate 400 corresponding to the support columns 103. When the cover plate 400 is covered on the device metal body 100, they are fixedly connected through bolt holes that commonly pass through the cover plate 400 and the support columns 103, thereby ensuring the firm connection between the cover plate 400 and the device metal body 100. The support columns 103 are located around the device metal body 100, which can disperse the pressure of the cover plate 400 and reduce local stress concentration.

[0046] It should be noted here that the support post 103, as the only contact point between the cover plate 400 and the device metal body 100, ensures that a designed air gap is maintained between the metal pin 401 and the device metal body 100, avoiding additional losses caused by direct contact between the metal pin 401 and the surface of the device metal body 100. At the same time, the height of the support post 103 is greater than that of the metal pin 401, which can also prevent the metal pin 401 from deforming and collapsing during assembly or external force extrusion, maintaining the electromagnetic characteristics of the gap waveguide.

[0047] As Figure 4 shown, in the embodiment of the present application, the gap waveguide filtering jumper further includes four resonant irises 300. Each resonant diaphragm communicates with the waveguide interface 101 and the central slot 200, and the resonant diaphragm is in the transverse electric wave resonance mode.

[0048] As Figure 4 and as Figure 6 shown, in the embodiment of the present application, an L -type capacitive stub 102 is provided at each waveguide interface 101. The L -type capacitive stub 102 is used to generate transmission zeros in the out-of-band frequency band.

[0049] As Figure 5 shown, in the embodiment of the present application, there are two signal transmission channels, and the two transmission channels are highly symmetric. For the convenience of description, it is stipulated that Figure 5 the transverse transmission channel in

[0050] is channel 1, and the longitudinal transmission channel is channel 2. It is stipulated that the waveguide interfaces 101 on both sides of channel 1 are the first port and the third port; the waveguide interfaces 101 on both sides of channel 2 are the second port and the fourth port. It is stipulated that the signal transmission direction of channel 1 is input from the first port and output from the third port; it is stipulated that the signal transmission direction of channel 2 is input from the second port and output from the fourth port. It is stipulated that the resonant irises 300 connected to the first, second, third, and fourth ports are called the first, second, third, and fourth resonant irises 300 respectively. It should be noted that the device in the embodiment of the present application is highly symmetric, and the selection of channel 1 and channel 2 and the signal transmission direction are not limited. In some possible implementation schemes, it is also feasible to arbitrarily exchange channel 1, channel 2, port numbers, or transmission directions in the description of the embodiment of the present application.

[0051] In the embodiments of the present application, for Channel 1, the signal is input from the first waveguide interface 101 and transmitted to the first resonant iris 300, where a second in-band resonance point is formed. Then, the signal of Channel 1 continues to be transmitted to the central resonant cavity, where TE 102 (transverse magnetic wave 102 mode) forms the first in-band resonance point. Then, the signal of Channel 1 continues to be transmitted to the second resonant iris 300, where a third in-band resonance point is formed. The three in-band resonance points constitute the passband. For Channel 2, the mechanism of generating the resonance point is basically the same as that described for Channel 1 above, but the mode excited in the central resonant cavity is TE 201 (transverse magnetic wave 201 mode).

[0052] In the above-excited modes, along the central cross-sectional direction of Channel 1, the electric field of the TE 102 mode is always the strongest, while the electric field of the TE 201 mode is always the weakest. On the contrary, along the central cross-sectional direction of Channel 2, the electric field distribution shows the opposite characteristics. The electric field of the TE 102 mode is always the weakest, while the electric field of the TE 201 mode is always the strongest. This excitation mode is called the degenerate orthogonal mode, which can achieve a high degree of isolation of the signals in the two transmission channels.

[0053] In the embodiments of the present application, for the main channel, the input / output port and the central resonant cavity generate cross-coupling to excite the first out-of-band transmission zero point, and the same L type capacitive stub generates the second out-of-band transmission zero point in the lower stopband.

[0054] Here, it should be noted that by adjusting the height of the central groove, the position of the first transmission zero point in the lower stopband can be changed. By adjusting the L parameters of the type capacitive stub, the position of the second transmission zero point in the lower stopband can be changed. The present application example does not limit the positions of the first and second transmission zero points.

[0055] In the embodiments of the present application, the electromagnetic simulation software (High Frequency Structure Simulator, HFSS) is used to optimize the parameters and adjust the appropriate parameters to meet the requirements of the filter jumper.

[0056] As Figure 7 shown, Figure 7 is the dispersion diagram of the metal pin 401 with periodic boundaries. The unit structure of the metal pin is added to the figure. The side length of the metal pin a = 1 mm, the height of the metal pin h = 3 mm, and the period of the metal pin p= 2.6 mm, air gap size g = 0.2 mm. The designed stopband ranges from 12.9 GHz to 47.5 GHz.

[0057] As Figure 8 shown, Figure 8 is the scattering parameter diagram of the filter jumper. The abscissa is the frequency range, used to analyze the performance of the device at different frequencies, and the ordinate is S the magnitude of the

[0058] parameter (Scattering Parameters). For the exemplary parameters designed for the filter jumper with input at the first port, output at the third port, and isolation between the second and fourth ports: in the Ka band, the insertion loss S 11 is 0.26 dB, the return loss S 31 is 22.1 dB, and the isolation S 21 is 33.1 dB.

[0059] The filter jumper of the present invention exhibits low insertion loss in the millimeter-wave band. This characteristic significantly improves the signal transmission efficiency, is particularly suitable for high-speed communication systems, reduces signal attenuation, and ensures high-quality signal transmission.

[0060] The filter jumper of the present invention achieves third-order filtering crossover by using a single generalized-connected gap waveguide resonator and combining a resonant diaphragm, and has a highly compact structure, making it easier to integrate into miniaturized electronic systems.

[0061] The filter jumper of the present invention utilizes precise degenerate modes to ensure excellent isolation performance. This high isolation performance effectively reduces signal interference, improves the overall stability and reliability of the system, and is particularly suitable for complex communication networks.

[0062] The filter jumper of the present invention realizes a transmission zero in the upper stopband through cross-coupling and realizes a transmission zero in the lower stopband by adding a capacitive stub. The two transmission zeros provide high frequency selectivity for the filter jumper of the present invention. This design with double transmission zeros significantly enhances the frequency selectivity of the filter, can more precisely separate the target frequency band, reduce signal crosstalk, and improve system performance.

[0063] The above are only the preferred embodiments of the present invention, and do not impose any other form of limitation on the present invention. Any modification or equivalent change made based on the technical essence of the present invention still falls within the scope claimed by the present invention.

Claims

1. A millimeter wave filter jumper based on a single slot gap waveguide cavity, comprising a device metal body (100), a central slot (200), four resonant irises (300) and a cover plate (400), characterized in that: The device metal body (100) is provided with four waveguide interfaces (101), the central slot (200) is provided in the device metal body (100), the four resonant irises (300) are provided in the device metal body (100), one end of the resonant irises (300) is connected to the waveguide interfaces (101) in a one-to-one correspondence, and the other end is connected to the central slot (200); the cover plate (400) is provided on the device metal body (100), metal pins (401) are arranged in rows along the four sides below the cover plate (400), a groove portion is formed in the center, an air gap is provided between the lower end of the metal pin (401) and the device metal body (100), thereby forming a non-contact electromagnetic bandgap structure, the air gap is less than 1 / 4λ, where λ is the wavelength corresponding to the center frequency of the gap waveguide jumper, and the central groove portion formed below the cover plate (400) and the central slot (200) form a resonant cavity; The waveguide interface (101) on the metal body (100) of the device is provided with a L Type capacitive short stub (102).

2. A millimeter wave filter jumper based on a single slot gap waveguide cavity according to claim 1, characterized in that: Support columns (103) are arranged at four corners of the metal body (100) of the device, the height of the support columns (103) is greater than the height of the metal pin (401), an internal thread section is constructed inside the support columns (103), and a through hole is arranged in an area of ​​the cover plate (400) corresponding to the support columns (103).

3. The millimeter wave filter jumper based on a single slot gap waveguide cavity according to claim 1, characterized in that: The metal body (100), central slot (200), four resonant irises (300) and cover plate (400) of a millimeter wave filter jumper based on a single slot gap waveguide cavity are made of a mixed polyurethane acrylic resin material and electroplated with a 10μm-12μm copper material.

4. The millimeter wave filter jumper based on a single slot gap waveguide cavity according to claim 1, characterized in that: The four waveguide interfaces (101) include two input interfaces and two output interfaces and are symmetrically arranged.

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