Millimeter wave rectangular waveguide embedded gap waveguide filter

Abstract

The invention provides a millimeter wave rectangular waveguide embedded gap waveguide filter. The filter comprises an upper metal cover plate, a middle metal block and a lower metal cover plate which are sequentially assembled from top to bottom, the upper metal cover plate is provided with a coaxial input port. The lower metal cover plate is provided with a coaxial output port. A first periodic metal pin array and a second periodic metal pin array are arranged on the upper surface and the lower surface of the middle metal block; gaps are formed between the first periodic metal pin array and the upper-layer metal cover plate and between the second periodic metal pin array and the lower-layer metal cover plate respectively; the first periodic metal pin array encloses a first slot gap waveguide resonant cavity on the upper surface of the middle metal block; the second periodic metal pin array encloses a second slot gap waveguide resonant cavity on the lower surface of the middle metal block; and a rectangular waveguide resonant cavity formed by hollowing in the middle metal block is respectively communicated with the first slot gap waveguide resonant cavity and the second slot gap waveguide resonant cavity.

Description

Technical Field

[0001] This invention belongs to the field of gap waveguide filter technology, and in particular relates to a millimeter-wave rectangular waveguide embedded gap waveguide filter. Background Technology

[0002] With the development of 5G mobile communication and future millimeter-wave wireless systems, the demand for high-performance, miniaturized filters is becoming increasingly urgent. The millimeter-wave band, due to its abundant spectrum resources and large available bandwidth, has become crucial for achieving high-speed data transmission. However, the shortening of wavelength also brings higher transmission losses and severe challenges to the performance and size of passive devices. Therefore, how to achieve low-loss, high-selectivity, and compact filters in the millimeter-wave band has always been a key research focus and challenge in this field. In recent years, gap waveguide technology, as an emerging platform, forms artificial magnetic conductors through periodic structures, effectively limiting the propagation of electromagnetic waves in pre-defined trenches or cavities without physical metal contact. This characteristic allows it to overcome, to some extent, the dependence on precision mechanical contact in traditional rectangular waveguides, showing promising application prospects. However, in existing gap waveguide filter designs, the resonant cavity is usually entirely composed of a periodic pin array and occupies independent physical space. While this structure solves the contact problem, its lateral dimensions are often limited to maintain the necessary electromagnetic bandgap, making further reduction difficult. This results in an overall filter structure that is not compact enough, and the integration level needs to be improved.

[0003] In summary, existing millimeter-wave filters struggle to achieve an ideal balance between miniaturization, high integration, and high performance. Therefore, there is an urgent need in this field for an innovative filter structure that combines the low-loss advantages of rectangular waveguides with the ease of manufacturing of gap waveguides, while overcoming the size and integration limitations of existing structures. This structure solves the problems of high assembly difficulty and cost by embedding a rectangular waveguide within the filter, achieving a more compact size, higher integration, and better frequency selectivity. Summary of the Invention

[0004] The purpose of this invention is to provide a millimeter-wave rectangular waveguide embedded gap waveguide filter that reduces assembly difficulty and cost while achieving a more compact size, higher integration, and better frequency selectivity.

[0005] To achieve the above objectives, this invention proposes a millimeter-wave rectangular waveguide embedded gap waveguide filter. The filter comprises, from top to bottom, an upper metal cover plate 100, a middle metal block 200, and a lower metal cover plate 300. The upper metal cover plate 100 is provided with a coaxial input port 101, and the lower metal cover plate 300 is provided with a coaxial output port 301. Furthermore, the coaxial input port 101 and the coaxial output port 301 are coaxial in the vertical direction. A first periodic array of metal pins is provided on the upper surface of the middle metal block 200. 201, a second periodic metal pin array 202 is provided on the lower surface; a first air gap is formed between the first periodic metal pin array 201 and the upper metal cover plate 100; a second air gap is formed between the second periodic metal pin array 202 and the lower metal cover plate 300; the first periodic metal pin array 201 forms a first slot gap waveguide resonant cavity 11 on the upper surface of the intermediate metal block 200; the second periodic metal pin array 202 forms a second slot gap waveguide resonant cavity 13 on the lower surface of the intermediate metal block 200; The interior of the intermediate metal block 200 is hollowed out to form a rectangular waveguide resonant cavity 12; the rectangular waveguide resonant cavity 12 is connected to the first slot gap waveguide resonant cavity 11 through a first coupling hole, and is connected to the second slot gap waveguide resonant cavity 13 through a second coupling hole; the first slot gap waveguide resonant cavity 11, the rectangular waveguide resonant cavity 12 and the second slot gap waveguide resonant cavity 13 are sequentially coupled to form a third-order bandpass filter structure.

[0006] Furthermore, the first slot gap waveguide resonant cavity 11 is provided with a first disturbance pin 203, and the second slot gap waveguide resonant cavity 13 is provided with a second disturbance pin 204.

[0007] Furthermore, the positions of the first disturbance pin 203 and the second disturbance pin 204 are adjustable, and the resonant frequency of the preset mode can be adjusted by adjusting their positions in the resonant cavity.

[0008] Furthermore, the first slot gap waveguide resonator 11 and the second slot gap waveguide resonator 13 are configured to operate in TE102 mode and TE201 mode, respectively, and the rectangular waveguide resonator 12 is configured to operate in TE101 mode.

[0009] Furthermore, the coaxial input port 101 and the coaxial output port 301 are respectively connected to the first slot gap waveguide resonator 11 and the second slot gap waveguide resonator 13, and respectively achieve impedance matching with the first slot gap waveguide resonator 11 and the second slot gap waveguide resonator 13.

[0010] Furthermore, the first air gap and the second air gap constitute an artificial magnetic conductor boundary to limit electromagnetic field leakage.

[0011] Beneficial effects: Compared with the prior art, the technical solution of the present invention has the following beneficial technical effects: (1) By embedding the rectangular waveguide resonator as an independent unit in the middle layer of the gap waveguide, the three-dimensional integration and spatial multiplexing of the structure are realized, which significantly reduces the lateral planar size and overall volume of the filter and is conducive to the miniaturization of the system equipment.

[0012] (2) The embedded structure forms a compact electromagnetic cavity, and each resonant unit is highly integrated in physical terms, forming a stable integrated mechanical structure, which not only improves the physical stability of the device, but also simplifies the overall assembly.

[0013] (3) Thanks to the effect of the perturbation pin, the filter can generate two controllable transmission zeros, achieving high frequency selectivity and excellent out-of-band suppression characteristics.

[0014] (4) This structure inherits the advantages of gap waveguide technology in terms of low physical contact requirements to a certain extent, reduces the dependence on extremely high precision machining, and helps to control manufacturing costs. Attached Figure Description

[0015] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, so as to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art. The advantages and implementation methods of the present invention will become more apparent. The content of the accompanying drawings is only used to illustrate and explain the present invention, but does not constitute any limitation on the present invention. In the accompanying drawings: Figure 1 This is a structural diagram of the present invention; Figure 2 This is a diagram showing the upper and lower layers of the present invention; Figure 3 This is a side view of the present invention; Figure 4 This is a graph of the S-parameters of the filter. Detailed Implementation

[0016] The embodiments of the present invention will now be described with reference to the accompanying drawings. The embodiments shown in the drawings are merely exemplary and intended to explain the principles of the present invention, and are not intended to limit the scope of the present invention.

[0017] like Figure 1 As shown, the present invention proposes a millimeter-wave rectangular waveguide embedded gap waveguide filter, including an upper metal cover plate 100, a middle metal block 200, and a lower metal cover plate 300. The upper metal cover plate is provided with a coaxial input port 101, and the lower metal cover plate is provided with a coaxial output port 301. The coaxial input port 101 and the coaxial output port 301 are vertically coaxial to realize energy input from the device and output from the device; the middle metal block 200 is connected to a periodic metal pin array 201 above and a periodic metal pin array 202 below. There is an air gap between the metal pin array 201 and the upper metal cover plate 100, and there is also an air gap between the metal pin array 202 and the lower metal cover plate 300. These two air gaps constitute the artificial magnetic conductor required for the gap waveguide, preventing energy leakage and reducing device loss.

[0018] The metal pin array 201 forms a space at the center of the upper surface of the intermediate metal block 200. This space is called the first slot gap waveguide resonant cavity 11, which is used to excite the TE102 mode and generate a resonant point. The metal pin array 202 also forms a space at the center of the lower surface of the intermediate metal block 200. This space is called the second slot gap waveguide resonant cavity 13, which is also used to excite the TE102 mode and generate a resonant point.

[0019] Inside the central metal block 200, three regions are hollowed out: a rectangular waveguide resonant cavity 12 and two coupling holes 205 connected to it. The rectangular waveguide resonant cavity 12 is connected to the first slot gap waveguide resonant cavity 11 and the second slot gap waveguide resonant cavity 13 through the coupling holes 205. The rectangular waveguide resonant cavity 12 can excite the TE101 mode and generate a resonant point. The coupling holes 205 enable the "first slot gap waveguide resonant cavity 11 - central rectangular waveguide resonant cavity 12 - second slot gap waveguide resonant cavity 13" to construct an energy coupling path, realizing the response of a three-resonant-point (i.e., third-order) bandpass filter.

[0020] The technical solution described above constructs a third-order rectangular waveguide embedded gap waveguide filter. This filter features low loss, high integration, and compact size. Furthermore, due to the presence of the artificial magnetic conductor boundary, it has good non-electrical contact properties and is suitable for operation in the millimeter-wave band.

[0021] Furthermore, the first perturbation pin 203 and the second perturbation pin 204 are respectively added to the first slot gap waveguide resonator 11 and the second slot gap waveguide resonator 13, and they are used to independently perturb the resonant frequency of the TE201 mode in the slot gap waveguide resonator 11 and 12. The TE201 mode excited by the coaxial input port 101 and the coaxial output port 301 in the slot gap waveguide resonator 11 and 12 cannot be effectively coupled through the coupling hole 205, thus generating two transmission zeros. The frequency positions of these two transmission zeros are the frequency positions of the TE201 mode excited in the first slot gap waveguide resonator 11 and the central rectangular waveguide resonator 12. Therefore, the transmission zeros can be controlled by the first perturbation pin 203 and the second perturbation pin 204.

[0022] The achieved filter effect is as follows Figure 4 As shown, the filter has a center frequency of 25.5 GHz, a 3dB bandwidth of 3.37%, an insertion loss of 0.17 dB, and a return loss better than 20 dB. Furthermore, two transmission zeros located in the upper stopband can be clearly observed; the first zero is located at approximately 26.74 GHz, and the second at approximately 27.11 GHz. The stopband range is greater than 1.14 times the center frequency, and the stopband rejection exceeds -40 dB, which is beneficial for improving the filter's frequency selectivity and upper stopband rejection.

[0023] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, chip, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, chip, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, chip, article, or apparatus that includes said element. The above descriptions are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A millimeter-wave rectangular waveguide embedded gap waveguide filter, characterized in that, The filter includes an upper metal cover plate (100), a middle metal block (200) and a lower metal cover plate (300) assembled from top to bottom. The upper metal cover plate (100) is provided with a coaxial input port (101), and the lower metal cover plate (300) is provided with a coaxial output port (301). Furthermore, the coaxial input port (101) and the coaxial output port (301) are coaxial in the vertical direction. The upper surface of the intermediate metal block (200) is provided with a first periodic metal pin array (201), and the lower surface is provided with a second periodic metal pin array (202); a first air gap is formed between the first periodic metal pin array (201) and the upper metal cover plate (100); a second air gap is formed between the second periodic metal pin array (202) and the lower metal cover plate (300); the first periodic metal pin array (201) forms a first slot gap waveguide resonant cavity (11) on the upper surface of the intermediate metal block (200); the second periodic metal pin array (202) forms a second slot gap waveguide resonant cavity (13) on the lower surface of the intermediate metal block (200). The interior of the intermediate metal block (200) is hollowed out to form a rectangular waveguide resonant cavity (12); the rectangular waveguide resonant cavity (12) is connected to the first slot gap waveguide resonant cavity (11) through the first coupling hole, and is connected to the second slot gap waveguide resonant cavity (13) through the second coupling hole; The first slot gap waveguide resonator (11), the rectangular waveguide resonator (12), and the second slot gap waveguide resonator (13) are sequentially coupled to form a third-order bandpass filter structure.

2. The millimeter-wave rectangular waveguide embedded gap waveguide filter according to claim 1, characterized in that, The first slot gap waveguide resonator (11) is provided with a first disturbance pin (203), and the second slot gap waveguide resonator (13) is provided with a second disturbance pin (204).

3. A millimeter-wave rectangular waveguide embedded gap waveguide filter according to claim 2, characterized in that, The positions of the first disturbance pin (203) and the second disturbance pin (204) are adjustable, and the resonant frequency of the preset mode can be adjusted by adjusting their positions in the resonant cavity.

4. A millimeter-wave rectangular waveguide embedded gap waveguide filter according to claim 1, characterized in that, The first slot gap waveguide resonator (11) and the second slot gap waveguide resonator (13) are configured to operate in TE102 mode and TE201 mode, respectively, and the rectangular waveguide resonator (12) is configured to operate in TE101 mode.

5. A millimeter-wave rectangular waveguide embedded gap waveguide filter according to claim 1, characterized in that, The coaxial input port (101) and coaxial output port (301) are connected to the first slot gap waveguide resonator (11) and the second slot gap waveguide resonator (13) respectively, and impedance matching is achieved with the first slot gap waveguide resonator (11) and the second slot gap waveguide resonator (13) respectively.

6. The millimeter-wave rectangular waveguide embedded gap waveguide filter according to any one of claims 1 to 5, characterized in that, The first air gap and the second air gap constitute the boundary of the artificial magnetic conductor.

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