Millimeter wave filtering jumper based on single-slot gap waveguide cavity

Abstract

The invention discloses a millimeter wave filtering jumper based on a single-slot gap waveguide cavity, and belongs to the technical field of microwaves, and the gap waveguide jumper comprises a device metal main body, a central slot, four resonant irises and a cover plate. Wherein the device metal main body is provided with four waveguide ports; a central slot arranged in the device metal main body; and the four resonant irises are arranged in the device metal main body, one ends of the four resonant irises are connected with the waveguide ports in a one-to-one correspondence manner, and the other ends of the four resonant irises are connected with the central slot. The cover plate is arranged on the device metal main body, and the periodic metal pins on the cover plate form a non-contact electromagnetic band gap structure to form a stop band. In addition, the groove on the cover plate and the central slot of the device metal main body form a resonant cavity. The gap waveguide jumper provided by the embodiment of the invention 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 invention relates to the technical field of communication antennas, and in particular 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 commonly used in wireless communication systems to suppress unwanted signals, while frequency dividers are often 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 a variety of filter jumper schemes based on planar structures. Although this type of structure has the advantages of easy processing and integration, its insertion loss is high in the millimeter wave frequency band, which makes it difficult to meet the needs of high-performance communication systems. In recent years, slot gap waveguides, as a new type of low-loss transmission line structure, have gradually become a research hotspot in millimeter wave device design. As a type of gap waveguide, slot gap waveguides effectively reduce the radiation loss and transmission loss of electromagnetic waves while maintaining good electromagnetic shielding properties. This structure provides a new technical path for the design of millimeter wave filter jumpers. However, existing research still has bottlenecks in the use of slot gap waveguides to realize filter jumpers. For example, how to achieve high selectivity in high frequency bands and the comprehensive optimization of structural compactness are still difficult problems to be solved.

[0004] Compared with the existing technology, the technical differences are as follows: Technical comparison with publication number CN115693064A "A filter jumper based on a hemispherical resonant cavity"; 1. CN115693064A adopts a filter jumper structure based on a hemispherical resonant cavity, including five hemispherical resonant cavities, of which the second hemispherical resonant cavity is the center and is connected to the other four resonant cavities in an integral manner through notch coupling. This study adopts a single-slot gap waveguide structure, including a device metal body, a central slot, four resonant irises and a cover plate. The periodic metal pins on the cover plate constitute a non-contact electromagnetic bandgap structure to form a stop band. Compared with CN111259890A, the single-slot gap waveguide structure used in this study is easier to achieve miniaturization and integration, and is suitable for 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, and is more suitable for working in the millimeter wave band.

[0005] Second, there is no transmission zero setting in CN115693064A, and the frequency selectivity of the device is limited to a certain extent. The transmission zero plays a key role in filter design. It can significantly suppress signal transmission at a specific frequency, thereby improving the frequency selectivity and stopband suppression capability of the filter. This study, by cross-coupling and adding capacitive stubs, generates a transmission zero in both the upper stopband and the lower stopband, increasing the frequency selectivity of the device. It can better meet the demand for high-performance filters in future communication technologies. Summary of the invention

[0006] In order to solve the above problems, the present invention proposes a millimeter wave filter jumper based on a single slot gap waveguide cavity, which is used to solve the problems of excessive loss, poor selectivity, large size and the like in the millimeter wave band in the related art of the filter jumper.

[0007] To achieve the above object, the technical solution adopted by the present invention is: A millimeter wave filtering jumper based on a single-slot gap waveguide cavity comprises a device metal body, a central slot, four resonant irises and a cover plate, wherein the device metal body is provided with four waveguide interfaces, the central slot is provided in the device metal body, the four resonant irises are provided in the device metal body, one end of the resonant irises is connected to the waveguide interface in a one-to-one correspondence, and the other end is connected to the central slot; the cover plate is provided on the device metal body, metal pins are arranged in rows along the four sides below the cover plate, a groove portion is formed in the center, an air gap is provided 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, wherein λ is the wavelength corresponding to the center frequency of the gap waveguide jumper, and the central groove portion formed below the cover plate and the central slot constitute a resonant cavity.

[0008] As a further improvement of the present invention, the waveguide interface on the metal body of the device is provided with an L-shaped capacitive stub on a side close to the resonant iris.

[0009] As a further improvement of the present invention, support columns are provided at the four corners of the metal body of the device, the height of the support columns is greater than the height of the metal pins, an internal thread section is constructed inside the support columns, and a through hole is provided in the area of ​​the cover plate corresponding to the support column.

[0010] As a further improvement of the present invention, the metal body, central slot, four resonant irises and cover plate of the millimeter wave filter jumper based on the single slot gap waveguide cavity are made of mixed polyurethane acrylic resin material and electroplated with 10μm-12μm copper material.

[0011] As a further improvement of the present invention, the four waveguide interfaces include two input interfaces and two output interfaces and are symmetrically arranged.

[0012] The beneficial effects of the present invention are as follows:

[0013] The filter jumper of the present invention exhibits low insertion loss in the millimeter wave frequency band. This feature significantly improves signal transmission efficiency, is particularly suitable for high-speed communication systems, reduces signal attenuation, and ensures high-quality signal transmission.

[0014] The filter jumper of the present invention realizes a third-order filter crossover by using a single generalized gap waveguide resonator and combining it with a resonant diaphragm, and has a highly compact structure, making it easier to integrate into a miniaturized electronic system.

[0015] The filter jumper of the present invention utilizes a precise 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.

[0016] The filter jumper of the present invention realizes a transmission zero point in the upper stop band by cross coupling, and realizes a transmission zero point in the lower stop band by adding a capacitive stub, and the two transmission zero points provide high frequency selectivity for the filter jumper of the present invention. This dual transmission zero point design significantly enhances the frequency selectivity of the filter, can more accurately separate the target frequency band, reduce signal crosstalk, and improve system performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the overall structure of the filter jumper in the embodiment of the present application; Figure 2 for Figure 1 A perspective view of the metal body of the device in the filter jumper; Figure 3 for Figure 1 Cover plate for the middle filter jumper; Figure 4 for Figure 1 A partial structural perspective view of the filter jumper in the middle; Figure 5 for Figure 3 A top view of the Figure 6 for Figure 1 Schematic diagram of the capacitor stub provided in the metal body of the filter jumper; Figure 7 is the dispersion diagram of a metal pin with periodic boundaries; Figure 8 is the scattering parameter diagram of the filter jumper; The component names are as follows: 100. Device metal body; 101. Waveguide interface; 102. LCapacitive stub; 103, support column; 200, central slot; 300, resonant iris; 400, cover plate; 401, metal pin. DETAILED DESCRIPTION

[0018] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments: 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 metal column array), thereby suppressing the propagation of electromagnetic waves in parallel plate mode, while allowing waves to be transmitted in a low-loss manner along specific paths (such as ridges, grooves or microstrip lines). In particular, the jumper manufactured under the guidance of slot gap waveguide technology, compared with traditional jumpers, can not only be used in the millimeter wave band, but also has the advantages of low insertion loss and high quality factor, and is an ideal RF front-end device.

[0019] However, the jumper structure using the slot gap waveguide principle in the related technology has been reported in small numbers and has been relatively thinly applied. It usually faces technical difficulties such as difficulty in balancing low insertion loss and small size and lack of transmission zero points, and has great application limitations.

[0020] Based on the above description, the gap waveguide filter jumper provided in the embodiment 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, 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 outputs from another waveguide port. Among them, the frequency of the input signal is filtered by the waveguide resonant cavity and the resonant diaphragm to remove unnecessary frequency components, and the TE 201 and TE 102 This pair of degenerate modes realizes the transmission and isolation of signals between channels, ultimately achieving the effect of filtering and avoiding interference between cross-signal transmission paths. By precisely controlling the size of the gap, signals of specific frequencies are selectively adjusted to optimize filtering performance, reduce contact loss and electromagnetic leakage, and ensure reliable transmission of high-frequency signals.

[0021] The waveguide filter power divider according to the embodiment of the present application is described below with reference to the accompanying drawings.

[0022] like Figure 1 ,like Figure 2 He Ru Figure 3As shown, the gap waveguide jumper of the embodiment of the present application includes a device metal body 100, a central slot 200 disposed on the device metal body 100, and a cover plate 400 covered on the device metal body 100. The device metal body 100 is provided with four waveguide interfaces 101 for input / output; the central slot 200 is disposed on the device metal body 100, and the central slot 200 is connected to the four waveguide interfaces 101. The cover plate 400 is covered on the device metal body 100, and the groove in the middle of the cover plate 400 and the central slot 200 disposed on the device metal body 100 are configured to form a waveguide resonant cavity with the central slot 200.

[0023] The cover plate 400 and the device metal body 100 together form a gap waveguide. Traditional waveguide jumpers generally require complex metal contact components and alignment accuracy, while the structure of the embodiment of the present application guides electromagnetic wave transmission in a contactless manner, thereby effectively reducing electrical contact losses. Accordingly, since no complex alignment process is required, the manufacturing and assembly process is also simplified, reducing manufacturing costs.

[0024] The device of the embodiment of the present application can be prepared by stereolithography 3D printing technology. The device is made of mixed polyurethane acrylic resin material and electroplated with 10 μ m-12 μ m copper material. Exemplarily, after the device is printed, electroplating 10 μ m copper layer.

[0025] Since the gap waveguide does not rely on the traditional transmission method of metal contact waveguide, but uses precise physical gap waveguide electromagnetic waves, that is, the core of the gap waveguide is to accurately control the size and shape of the gap in the structure. Therefore, the use of stereolithography 3D printing technology can ensure that the size of the device meets the use requirements, and through electroplating copper materials to ensure that the metal surface is smooth and has low electromagnetic wave reflection loss, thereby achieving good gap waveguide performance. As an alternative implementation, electroplated copper can also be replaced by other metal materials, such as metal silver, gold or other conductive materials.

[0026] The four waveguide interfaces 101 provided on the device metal body 100 are used to receive external signals and introduce the signals into the gap waveguide filter jumper for processing. 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 connection and usage scenarios are only for illustration. For different usage scenarios, the device port actually connected to the device metal body 100 is also different.

[0027] The four waveguide interfaces 101 may be connected to an external device via a standard waveguide, or connected to an external device via a coaxial cable, or connected to a waveguide flange of an external device via bolts, and this embodiment of the present application does not impose an absolute limitation on this.

[0028] like Figure 2 and Figure 3 As shown, in the embodiment of the present application, a plurality of metal pins 401 are arranged in an array on one side of the cover plate 400 facing the device metal body 100. When the cover plate 400 is buckled with 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 resonant cavity.

[0029] It should be noted that the metal pins 401 on the cover plate 400 are of the same length and evenly distributed, forming an electromagnetic band gap structure (EBG), which effectively suppresses electromagnetic leakage in non-waveguide paths, ensures that the waveguide signal only travels along the central slot 200, and reduces radiation loss. The gap between the metal pins 401 and the central slot 200 is kept consistent to prevent signal reflection, waveguide loss or distortion caused by uneven gaps.

[0030] Here, the distance between the central slot 200 and the metal pin 401 is less than 1 / 4 λ , λ is the wavelength corresponding to the center frequency of the filter jumper.

[0031] A plurality of support columns 103 are protrudingly constructed on the device metal body 100 . The support columns 103 are used to support the cover plate 400 . The height of the support columns 103 is greater than the height of the metal pins 401 .

[0032] The support columns 103 are arranged on the edges of the device metal body 100, and the support columns 103 are internally threaded. The cover plate 400 is provided with through holes in the area corresponding to the support columns 103. When the cover plate 400 is covered on the device metal body 100, the cover plate 400 is fixedly connected by bolt holes passing through the cover plate 400 and the support columns 103, thereby ensuring the tight 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.

[0033] It should be noted here that the support column 103, as the only contact point between the cover plate 400 and the metal body 100 of the device, ensures that the designed air gap is maintained between the metal pin 401 and the metal body 100 of the device, avoiding additional losses caused by direct contact between the metal pin 401 and the surface of the metal body 100 of the device. At the same time, the height of the support column 103 is greater than the height of the metal pin 401, which can also prevent the metal pin 401 from deforming and collapsing during assembly or external force extrusion, thereby maintaining the electromagnetic characteristics of the gap waveguide.

[0034] like Figure 4 As shown, in the embodiment of the present application, the gap waveguide filter jumper further includes four resonant irises 300 , each resonant iris 300 is connected to the waveguide interface 101 and the central slot 200 , and the resonant iris 300 is in a transverse electric wave resonance mode.

[0035] like Figure 4 He Ru Figure 6 As shown, in the embodiment of the present application, each waveguide interface 101 is provided with L type capacitive stub 102, the L The capacitive stub 102 is used to generate a transmission zero in the out-of-band frequency band.

[0036] like Figure 5 As shown, in the embodiment of the present application, there are two transmission channels for signal transmission, and the two transmission channels are highly symmetrical; for the convenience of description, it is specified that Figure 5 The horizontal transmission channel is channel 1, and the vertical transmission channel is channel 2; the waveguide interfaces 101 on both sides of channel 1 are specified as the first port and the third port; the waveguide interfaces 101 on both sides of channel 2 are specified as the second port and the fourth port. The signal transmission direction of channel 1 is specified as input from the first port and output from the third port; the signal transmission direction of channel 2 is specified as input from the second port and output from the fourth port. The resonant irises 300 connected to the first, second, third, and fourth ports, respectively, are specified to be called the first, second, third, and fourth resonant irises 300. It should be noted that the device of the example of the present application is highly symmetrical, and the selection of channel 1 and channel 2 and the transmission direction of the signal are not limited. In some possible implementation schemes, it is also feasible to arbitrarily exchange channel 1, channel 2, port numbers, or transmission directions described in the example of the present application.

[0037] In the embodiment of the present application, after the cover plate 400 is covered on the metal body 100 of the device, a resonant cavity is formed by the middle groove of the cover plate and the central slot. For the convenience of description, the resonant cavity is defined as a central resonant cavity.

[0038] In the embodiment of the present application, for channel 1, the signal is input from the first waveguide interface 101, transmitted to the first resonant iris 300, and a second in-band resonant point is formed in the first resonant iris 300. After that, the channel 1 signal continues to be transmitted to the central resonant cavity, and TE is excited in the central resonant cavity. 102 (Transverse magnetic wave 102 mode) forms the first in-band resonance point, and then the channel 1 signal continues to be transmitted to the second resonant iris 300, forming the third in-band resonance point in the second resonant iris 300, and the three in-band resonance points constitute the passband. For channel 2, the mechanism of resonance point generation is basically the same as that described in the above channel 1, but the mode excited in the central resonant cavity is TE 201 (Transverse magnetic wave 201 mode).

[0039] In the above excited mode, along the central cross section of channel 1, TE 102 The electric field of the TE mode is always the strongest, and 201 The electric field of the mode is always the weakest. On the contrary, along the central cross section of channel 2, the electric field distribution presents the opposite characteristics, TE 102 The electric field of the TE mode is always the weakest, and 201 The electric field of the mode is always the strongest. This excitation mode is called a degenerate orthogonal mode and can achieve a high degree of isolation of the signals of the two transmission channels.

[0040] In the embodiment 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 each port has the same L The capacitive stub creates a second out-of-band transmission zero in the lower stop band.

[0041] Here, it should be noted that by adjusting the height of the central groove, the position of the first transmission zero point of the lower stop band can be changed. L The parameters of the capacitive stub can change the position of the second transmission zero point in the lower stop band. The present application example does not limit the positions of the first and second transmission zero points.

[0042] In the embodiment of the present application, electromagnetic simulation software (High Frequency Structure Simulator, HFSS) is used to optimize the parameters, and appropriate parameters are adjusted to meet the requirements of the filter jumper.

[0043] like Figure 7 As shown, Figure 7 is a dispersion diagram of a metal pin 401 with periodic boundaries. The unit structure of the metal pin is added to the figure. a =1 mm, metal pin height h =3 mm, metal pin period p=2.6 mm, air gap size g =0.2 mm. The designed stopband range extends from 12.9 GHz to 47.5 GHz.

[0044] like Figure 8 As shown, Figure 8 This is the scattering parameter diagram of the filter jumper. The horizontal axis is the frequency range, which is used to analyze the performance of the device at different frequencies. The vertical axis is S The magnitude of the parameters (Scattering Parameters) used to analyze the performance of multiport networks.

[0045] The exemplary parameter design of the filter jumper designed with the first port input, the third port output, and the second and fourth ports isolated is: Ka Band, insertion loss S 11 The return loss is 0.26 dB S 31 22.1 dB, isolation S 21 is 33.1 dB.

[0046] The filter jumper of the present invention exhibits low insertion loss in the millimeter wave frequency band. This feature significantly improves signal transmission efficiency, is particularly suitable for high-speed communication systems, reduces signal attenuation, and ensures high-quality signal transmission.

[0047] The filter jumper of the present invention realizes a third-order filter crossover by using a single generalized gap waveguide resonator and combining it with a resonant diaphragm, and has a highly compact structure, making it easier to integrate into a miniaturized electronic system.

[0048] The filter jumper of the present invention utilizes a precise 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.

[0049] The filter jumper of the present invention realizes a transmission zero point in the upper stop band by cross coupling, and realizes a transmission zero point in the lower stop band by adding a capacitive stub, and the two transmission zero points provide high frequency selectivity for the filter jumper of the present invention. This dual transmission zero point design significantly enhances the frequency selectivity of the filter, can more accurately separate the target frequency band, reduce signal crosstalk, and improve system performance.

[0050] The above description is only a preferred embodiment of the present invention and does not constitute any other form of limitation to the present invention. Any modification or equivalent change made based on the technical essence of the present invention still falls within the scope of protection required 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.

2. A millimeter wave filter jumper based on a single slot gap waveguide cavity according to claim 1, characterized in that: The waveguide interface (101) on the metal body (100) of the device is provided with a L Type capacitive short stub (102).

3. The 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).

4. 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.

5. 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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