CN114843730A

CN114843730A - Millimeter wave high selectivity gap waveguide filter

Info

Publication number: CN114843730A
Application number: CN202210428472.1A
Authority: CN
Inventors: 吴永乐; 王杰; 王卫民
Original assignee: Beijing University of Posts and Telecommunications
Current assignee: Beijing University of Posts and Telecommunications
Priority date: 2022-04-22
Filing date: 2022-04-22
Publication date: 2022-08-02

Abstract

The invention provides a millimeter wave high selectivity gap waveguide filter, comprising: upper metal cover plate, lower floor's metal flat board, first feed port and second feed port, upper metal cover plate passes through the support column with lower floor's metal flat board and is connected and fixed, have on lower floor's the face that is close to upper metal cover plate: the input cavity and the output cavity are respectively communicated with the first feeding port and the second feeding port; the metal pins are closely arranged at preset intervals, a rectangular resonant cavity is formed in the center of the lower metal flat plate in a surrounding mode, the resonant cavity is communicated with the input cavity and the output cavity, and the height of each metal pin is lower than that of each support column; the central resonant columns are positioned in the center of the resonant cavity and are distributed in central symmetry; and the tuning pin is positioned at the position where the input cavity, the output cavity and the resonant cavity are communicated. The invention can realize the miniaturization and low loss of the filter and the high selectivity of millimeter wave band signals.

Description

Millimeter wave high selectivity gap waveguide filter

Technical Field

The invention relates to the technical field of millimeter wave devices, in particular to a millimeter wave high-selectivity gap waveguide filter.

Background

In recent years, with the steady development of the 5G communication era, the requirements of wireless communication systems for data signal transmission are also increased, and the wireless communication systems tend to be more broadband and higher in speed, which also promotes the working frequency band to develop towards the millimeter wave frequency band with wider frequency spectrum resources. The filter is used as a front-end module of the radio frequency system, plays a role in screening and extracting the frequency of signal transmission, and the performance of the filter has an important influence on the whole radio frequency system, so that the filter is also developed towards miniaturization, low loss and high out-of-band rejection. Filters designed by adopting the traditional microstrip line technology are difficult to meet the requirements at the same time, and a novel filter is urgently needed to be designed to meet higher development requirements.

Gap waveguide technology was first proposed in 2009 by P-s.kildal and was subsequently widely used by numerous scholars in the design of various types of passive devices and antennas, specifically to create transmission paths by introducing periodic pins on a metal plate to achieve specific transmission and coupling of electromagnetic wave signals. The process flow of the gap waveguide technology includes milling, electric discharge, surface grinding treatment, etc., and each layer is independently processed and then fixed by screws.

At present, most of band-pass filters based on the gap waveguide technology generate transmission zero points according to a cross-coupling structure, and generally four or more resonant cavities are cascaded, but the structural size of the device is greatly increased by the cascading mode, which is not beneficial to achieving a miniaturization target.

Therefore, how to provide a miniaturized, high-selectivity and high-out-of-band rejection filter is a problem to be solved urgently.

Disclosure of Invention

In view of the problems in the prior art, an object of the present invention is to provide a millimeter wave high selectivity gap waveguide filter, which is used to provide a gap waveguide filter with miniaturization, high selectivity and high out-of-band rejection, and can realize the miniaturization of the filter structure, low loss of signal transmission, high out-of-band signal rejection and high selectivity for millimeter wave band signals.

One aspect of the present invention provides a millimeter wave highly selective gap waveguide filter, the gap waveguide filter structure comprising: upper metal covering plate, lower floor's metal flat board, first feed port and second feed port, upper metal covering plate with lower floor's metal flat board passes through the support column to be connected and fixed, first feed port with lower floor's metal flat board's relative two sides are arranged respectively in to the second feed port, have on lower floor's the metal flat board's of being close to upper metal covering plate's the face: the input cavity and the output cavity are respectively communicated with the first feeding port and the second feeding port; the metal pins are closely arranged at preset intervals, a rectangular resonant cavity is formed in the center of the lower metal flat plate in a surrounding mode, the resonant cavity is communicated with the input cavity and the output cavity, the height of each metal pin is lower than that of the support column, and an air gap layer between the upper metal cover plate and the upper surface of each metal pin is formed; the central resonant columns are positioned at the centers of the resonant cavities and are distributed in a centrosymmetric manner; and the tuning pin is positioned at the position where the input cavity and the output cavity are communicated with the resonant cavity.

In some embodiments of the present invention, the supporting columns are located at four corners of the inner surface of the lower metal plate, and the supporting columns and the lower metal plate are in an integrally formed structure; the upper-layer metal cover plate further comprises a plurality of screws, and the plurality of screws correspond to the supporting columns respectively and are used for fixing the upper-layer cover plate and the lower-layer metal flat plate.

In some embodiments of the present invention, the first feeding port and the second feeding port use a standard rectangular waveguide port WR-14 for feeding and receiving signals, and have a length of 3.759mm and a width of 1.88 mm.

In some embodiments of the present invention, the first feeding port and the second feeding port are arranged in a central symmetry, and the input cavity and the output cavity are also arranged in a central symmetry.

In some embodiments of the present invention, the central resonant columns have one or two rows, and each row of the central resonant columns contains 2 or 3 central resonant columns.

In some embodiments of the present invention, two of the tuning pins are distributed in a centrosymmetric manner at positions where the resonant cavity is communicated with the input cavity and the output cavity respectively.

In some embodiments of the invention, the input and output chambers are chamfered at the corners.

In some embodiments of the invention, the lower metal plate and the metal pins, the central resonating column and the tuning pins are integrally formed during the manufacturing process.

In some embodiments of the invention, the input cavity, the output cavity and the first and second feed ports are rectangular in shape, and the metal pin, the central resonant column and the tuning pin are cylindrical or square prism in shape.

In some embodiments of the invention, the height of the metal pin is greater than the height of the center resonant post, which is greater than the height of the tuning pin.

The millimeter wave high-selectivity gap waveguide filter can realize the miniaturization of the filter structure, the low loss of signal transmission, the high out-of-band signal suppression and the high selectivity to millimeter wave band signals.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and drawings.

It will be appreciated by those skilled in the art that the objects and advantages that can be achieved with the present invention are not limited to the specific details set forth above, and that these and other objects that can be achieved with the present invention will be more clearly understood from the detailed description that follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. For purposes of illustrating and describing some portions of the present invention, corresponding parts of the drawings may be exaggerated, i.e., may be larger, relative to other components in an exemplary apparatus actually manufactured according to the present invention. In the drawings:

fig. 1 is a schematic perspective view of a millimeter-wave high selectivity gap waveguide filter according to an embodiment of the present invention.

Fig. 2 is a schematic structural diagram of an appearance of a millimeter-wave high selectivity gap waveguide filter according to an embodiment of the present invention.

Fig. 3 is a schematic diagram of a structure diagram of a periodic metal pin unit and a simulation result of a dispersion curve thereof according to an embodiment of the present invention.

Fig. 4 is a top view of a planar structure of a millimeter-wave high selectivity gap waveguide filter according to an embodiment of the present invention.

Fig. 5 is a diagram illustrating simulation results of S-parameters of a millimeter-wave high selectivity gap waveguide filter according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the following embodiments and accompanying drawings. The exemplary embodiments and descriptions of the present invention are provided to explain the present invention, but not to limit the present invention.

It should be noted that, in order to avoid obscuring the present invention with unnecessary details, only the structures and/or processing steps closely related to the scheme according to the present invention are shown in the drawings, and other details not so relevant to the present invention are omitted.

It should be emphasized that the term "comprises/comprising" when used herein, is taken to specify the presence of stated features, elements, steps or components, but does not preclude the presence or addition of one or more other features, elements, steps or components.

It is also noted herein that the term "coupled," if not specifically stated, may refer herein to not only a direct connection, but also an indirect connection in which an intermediate is present.

In order to solve the problems of the existing filter structure and realize the miniaturization of the filter structure, the low loss of signal transmission, the high out-of-band signal suppression and the high selectivity of millimeter wave band signals, the invention provides a millimeter wave high selectivity gap waveguide filter, which adopts a gap waveguide structure to design the filter, creatively adds a plurality of central resonance columns in a gap waveguide resonant cavity, and the design is that a central symmetrical structure has transmission zero points at both sides of a passband.

The gap waveguide structure not only keeps the advantages of the traditional metal waveguide, but also greatly reduces the difficulty of processing and assembling, thereby having the characteristics of low cost and easy assembly. On the other hand, the gap waveguide structure has very low transmission loss in a millimeter wave frequency band, namely, the signal transmission effect is excellent while a wider pass band is kept, so that the gap waveguide structure has the characteristics of low loss and broadband. The advantages of low cost, easy assembly, high performance and the like enable the gap waveguide technology to have rich application prospect and practical value in millimeter wave and higher frequency bands.

The design that a plurality of center resonance columns are added in a gap waveguide resonant cavity aims at introducing resonance modes with different frequencies, namely, the resonant cavity has multimode characteristics, and then a transmission zero point is generated through the coupling effect among different resonance modes, so that the high selectivity of the frequency is realized, the good transmission effect of a band-pass filter is ensured, the miniaturized design target is realized, and the band-pass filter can be well applied to millimeter waves and higher frequency bands. Furthermore, the height of the central resonance column can be changed, so that the frequencies of different resonance modes can be changed, and the purpose of adjusting the position of the transmission zero point can be achieved.

Fig. 1 is a schematic perspective view of a millimeter-wave high selectivity gap waveguide filter according to an embodiment of the present invention, in which a perspective view of the gap waveguide filter is shown and various parts are labeled and distinguished in detail, and the gap waveguide filter includes the following structures: the antenna comprises an upper-layer metal cover plate 1, a lower-layer metal flat plate 2, a resonant cavity 3, a plurality of metal pins 10, a plurality of central resonant columns 11, tuning pins 12, a first feeding port 13, a second feeding port 14, an input cavity 15, an output cavity 16, a support column 17 and screws 18.

In the embodiment of the present invention, the upper metal cover plate 1 and the lower metal flat plate 2 are connected and fixed by the supporting column 17, the first feeding port 13 and the second feeding port 14 are respectively disposed on two opposite side surfaces of the lower metal flat plate, and a surface of the lower metal flat plate 2 close to the upper metal cover plate 1 has: an input cavity 15 and an output cavity 16 communicating with the first feeding port 13 and the second feeding port 14, respectively; the metal pins 10 are closely arranged at preset intervals, a rectangular resonant cavity 3 is formed around the center of the lower metal flat plate, the resonant cavity 3 is communicated with an input cavity 15 and an output cavity 16, the height of each metal pin 10 is lower than that of a support column 17, and an air gap layer between the upper metal cover plate 1 and the upper surface of each metal pin 10 is formed; the central resonant columns 11 are positioned at the center of the resonant cavity 3 and are distributed in a centrosymmetric manner; and a tuning pin 12 located at a position where the input chamber 15 and the output chamber 16 communicate with the resonance chamber 3.

In an embodiment of the present invention, the supporting pillars 17 are located at four corners of the inner surface of the lower metal plate 2, and the supporting pillars 17 and the lower metal plate 2 are integrally formed. The upper layer metal cover plate 1 further comprises a plurality of screws 18, and the plurality of screws 18 correspond to the support columns 17 respectively and are used for fixing the upper layer cover plate and the lower layer metal flat plate. Specifically, in the embodiment of the present invention, there are four support columns 17 and four screws 18, which are respectively located at four corners. It should be noted that the position on the support column 17 corresponding to the screw 18 selected in the embodiment of the present invention may be a screw hole drilled in advance, or may be a screw hole drilled during connection and fixation. The supporting and fixing manner by the supporting column 17 and the screw 18 is only an example, and the present invention is not limited thereto, and for example, various supporting and fixing methods such as integral forming and snap fixing may be used, and other alternatives that are easily conceivable by those skilled in the art should fall within the protection scope of the present invention.

In one embodiment of the present invention, the first feeding port 13 and the second feeding port 14 use a standard rectangular waveguide port WR-14 for feeding and receiving signals, and the dimensions of the feeding port are 3.759mm in length and 1.88mm in width, which are fixed dimensions of the standard rectangular waveguide port WR-14. The first and

second feeding ports

13 and 14 are arranged in a centrosymmetric manner, and the input cavity 15 and the output cavity 16 are also arranged in a centrosymmetric manner. It should be noted that, the embodiment of the present invention follows a central symmetry structure as a whole in the structure, thereby bringing two transmission zeros and having a left-right substantial symmetry. The transmission zero brings the effect of high selectivity to the filter, and the design of the invention brings two transmission zeros, thereby bringing better high selectivity.

In the embodiment of the present invention, the resonant cavity 3 plays a role of isolating leakage of electromagnetic waves. Introduce central resonance post 11 in resonant cavity 3, central resonance post 11 is 3 one row, two rows of distributions along the central axis symmetry, the central point that is located lower floor's metal flat 2 puts, totally 6, the size is identical completely, play the effect that forms multiple resonance mode in resonant cavity 3, can change the mode distribution of empty resonant cavity 3 promptly, through rationally arranging central resonance post 11 the position and selecting the size parameter, can form multiple resonance mode at required frequency channel, and then form transmission zero point through the interact between the mode. The specific number and arrangement of the central resonant columns are only examples, and the present invention is not limited thereto, and the central resonant column 11 may have one row or two rows, each row of the central resonant columns includes 2 or 3 central resonant columns, for example, there may also be two rows of the central resonant columns, each row has two, for a total of 4 central resonant columns.

In an embodiment of the present invention, two tuning pins 12 are distributed in a centrosymmetric manner at the positions where the resonant cavity 3 communicates with the input cavity 15 and the output cavity 16, respectively. The tuning pins 12 are distributed on the adjacent edges of the resonant cavity 3 and the input cavity 15 and the output cavity 16 in a central symmetry manner, so as to adjust the coupling between the input cavity 15 and the resonant cavity 3 and the coupling between the output cavity 16 and the resonant cavity 3, i.e. the resonant frequencies of the multiple resonant modes can be slightly adjusted, and the coupling effect among different modes can be enhanced. The input cavity 15 and the output cavity 16 are respectively used for transmitting signals fed from the first feeding port 13 and the second feeding port 14, and are connected with the resonant cavity 3 to form a plurality of resonant modes, and further, different transmission zero points are generated by interaction among the plurality of resonant modes, so that an effect of high selectivity is achieved.

With reference to fig. 1, the principle of generating transmission zero point by various specific resonance modes of the present invention is as follows: two rows of central resonant columns 11 are introduced into the resonant cavity 3, and form a complete filter structure together with the input cavity 15 and the output cavity 16. Four resonance modes are introduced near a required frequency band of 60GHz, and are TE102, TE202, TE301 and TE401 modes from low to high in sequence according to resonance frequency, wherein the TE102 mode and the TE202 mode are coupled pairwise to generate a transmission zero point on the left side of a passband; the TE301 mode and the TE401 mode are coupled to each other, and a transmission zero point on the right side of the passband is generated. Therefore, the effect of generating transmission zero points on the left and right sides of the passband can be achieved in the resonator 3 with a smaller size by the multimode effect, and the passband is wider and the transmission loss is smaller. The central resonator post 11 also has the effect of adjusting the resonant frequency of the cavity modes. The mode of generating transmission zero points depends on the coupling action among multiple modes in the resonant cavity 3, the multiple modes are generated by introducing a plurality of central resonant columns in the resonant cavity, the mode of generating transmission zero points on two sides of a passband greatly reduces the number and the volume of the resonant cavity in the traditional cross coupling mode and the like, and simultaneously achieves good transmission effect, thereby realizing the design targets of miniaturization, high performance and high selectivity. The coupling combination of the four resonant modes is only an example, and the invention is not limited thereto, and in the embodiment of the invention, the TE102 and the TE202 interact with each other, and the TE301 and the TE401 interact with each other, or there may be other combinations, but the generation of the transmission zero point may also be changed adaptively.

In one embodiment of the present invention, the input cavity 15, the output cavity 16 and the first and

second feeding ports

13 and 14 are rectangular in shape, and the metal pin 10, the central resonant column 11 and the tuning pin 12 are square prisms in shape. The shapes of the metal pin 10, the central resonance column 11 and the tuning pin 12 are merely examples, and the present invention is not limited thereto, and may be, for example, a cylinder, that is, the shapes of the upper and lower bottom surfaces of the metal pin 10, the central resonance column 11 and the tuning pin 12 may be a square or a circle.

It should be noted that the metal materials adopted in the present invention are all ideal electrical conductors, that is, the present invention does not adopt the conventional techniques of metal waveguides, dielectric filters, substrate integrated waveguides, etc., but is constructed based on the gap waveguide technique, and while maintaining good filtering performance, the present embodiment also has the advantages of convenient processing and assembly, small size, low cost, etc.

Fig. 2 is a schematic structural diagram of an appearance of a millimeter-wave high selectivity gap waveguide filter according to an embodiment of the present invention. The completed structure of millimeter wave high selectivity gap waveguide filter 100 is shown in the figure, wherein it can be clearly seen that the upper metal cover plate 1 is connected to the lower metal flat plate 2 through the four corner supporting posts 17 with identical size, and is fixed by the screws 18, and the height of the supporting posts 17 is the sum of the heights of the periodic metal pins 10 and the air gap layer 19, so as to ensure the existence of the air gap layer 19. It should be noted that the supporting columns 17 and the screws 18 have no influence on the transmission effect of the millimeter wave high selectivity gap waveguide filter, and only serve as fixed supports and connections. Fig. 1 is a view for clearly showing the internal structure of a gap waveguide filter, fig. 2 is a view showing a complete and real gap waveguide filter structure, and an upper layer metal cover plate, a lower layer metal flat plate and an upper structure are connected and fixed together by means of screws, fasteners, welding and the like.

In the embodiment of the present invention, the height of the metal pin 10 is greater than that of the central resonance column 11, and the height of the central resonance column 11 is greater than that of the tuning pin 12. Also, the height of the metal pin 10 is smaller than the height of the support column 17. It should be noted that this height relationship is fixed because the air gap layer is an indispensable part of the present invention. However, the heights of the metal pin 10, the center resonance post 11, and the tuning pin 12 of the present invention are not limited thereto, and the frequency range of out-of-band suppression or high selectivity may be changed by adjusting the heights of the three.

Fig. 3 is a schematic diagram of a structure diagram of a periodic metal pin unit and a simulation result of a dispersion curve thereof according to an embodiment of the present invention. Specifically, the metal pins can form a stopband, the stopband range is 50-89GHz, namely, the electromagnetic waves in the resonant cavity cannot pass through the boundary formed by the periodic pins in the frequency band, so that the electromagnetic wave resonant cavity plays a good role in isolation and encapsulation, and an additional structure is not required to be introduced. In the embodiment of the present invention, the sizes of the metal pins 10 are respectively that the gap height g is 0.25mm, the height h of the metal pin 10 is 1.25mm, the width a is 0.4mm, and the distribution period p is 0.8 mm. The gap waveguide technology adopts a plurality of metal pins which are periodically arranged to form a wave stop band, so that the energy leakage is avoided, the transmission loss is extremely low, the processing and the assembly are very simple and convenient without strict electric contact, and the gap waveguide technology can be well applied to millimeter waves and higher frequency bands. Mode 1, mode 2, and mode 3 shown in fig. 3 are stray modes of the metal pin at this size, indicating the isolated, encapsulated frequency range of the metal pin at the above size.

In an embodiment of the present invention, the input cavity 15 and the output cavity 16 are chamfered at the corners, which is more beneficial for manufacturing.

In one embodiment of the present invention, the lower metal plate 2, the metal pin 10, the central resonance column 11 and the tuning pin 12 are integrally formed during the manufacturing process, and the integral structure is more stable.

FIG. 4 is a top view of a planar structure of a millimeter-wave high selectivity gap waveguide filter with a design of dimensional parameters. Wherein the overall dimensions of the Gap Waveguide Filter are only 2.56 λ g, 1.68 λ g respectively, compared to the "Miniaturized W-Band Gap Waveguide Band Filter Using the MEMS Technology for the bath Waveguide and Surface Mounted Packaging" proposed by Shi yongnong et al in 2019, the "A Novel Iris Waveguide Band Filter Using Air filtered Waveguide Technology" proposed by Sun donggan et al in 2016, the "A Novel Iris Waveguide Band Filter Using Air Waveguide Technology" in 3.88 λ g, 2.61 λ g. By comparison, it can be seen that the embodiments of the present invention satisfy the advantage of small size. The physical meaning of λ g is waveguide wavelength, which is a unit of length, and the wavelength λ c/f corresponding to 60GHz is 5mm, and the actual length and width of the filter is 12.8mm and 8.4mm, so that 12.8/5 is 2.56 λ g, and 8.4/5 is 1.68 λ g.

In the embodiment of the invention, the side length of the bottom surface of the central resonance column 11 is 0.4mm, the height of the bottom surface of the central resonance column is 0.8mm, and the transverse distance a and the longitudinal distance b between the bottom surface of the central resonance column and the bottom surface of the central resonance column are respectively 0.755mm and 1.84 mm; the length l and the width c of the resonant cavity 3 are respectively 6.19mm and 4.4 mm; the tuning pin 12 also has a bottom surface with a side length of 0.4mm and a height of 0.53 mm. The length of the input cavity 15 and the length of the output cavity 16 are both 4.52mm, and the corners are chamfered, so that the processing and the manufacturing are more facilitated. The size of the center resonance column 11 is merely an example, and the present invention is not limited thereto, and the frequency range can be adjusted by adjusting the height of the center resonance column 11.

Fig. 5 is a diagram illustrating simulation results of the S-parameter of a millimeter wave high selectivity gap waveguide filter in accordance with one embodiment of the present invention. Including return loss (| S) ₁₁ I) and insertion loss (| S) ₂₁ The millimeter-wave high-selectivity gap waveguide filter provided by the embodiment of the invention works in a V wave band, the passband is 58.32-62.91GHz, the width is 4.59GHz, the relative bandwidth reaches 7.57%, the in-band insertion loss is less than 0.1dB, the return loss is better than 20dB, the transmission zero point on the left side of the passband is 56.79GHz, the out-of-band rejection exceeds 20dB, the transmission zero point on the right side of the passband is 64.92GHz, and the out-of-band rejection exceeds 28 dB. It can be seen that the gap waveguide filter has high selectivity, two transmission zeros are close to a passband, the out-of-band drop is very fast, the insertion loss is less than 0.1dB, the return loss is higher than 20dB, the signal transmission is excellent, and the performance of the gap waveguide filter is superior to that of many bandpass filters constructed by microstrip lines, dielectric waveguides and the like in a relative passband bandwidth of 4.59 GHz.

The millimeter wave high-selectivity gap waveguide filter provided by the embodiment of the invention works near 60GHz, has a broadband characteristic, is extremely low in pass band loss, and can be well applied to various scenes. It should be explained that the 60GHz band is an operating band of a satellite antenna, a radar, and the like, and is a key band for millimeter wave design. Has rich application. Therefore, the embodiment of the present invention selects this frequency band. The band of operation of the filter of 60GHz is merely an example, and the present invention is not limited thereto, and the band of operation of the filter can be changed by adjusting the heights of the metal pin 10, the center resonance column 11, and the tuning pin 12.

Furthermore, it should be noted that, in the embodiment of the present invention, the millimeter wave gap waveguide filter is centrosymmetric, so that the partial structures are completely consistent and symmetrically distributed, and therefore the same reference numerals are used. The present invention is not limited thereto, and the input cavity 15 and the output cavity 16 are switchable due to the centrosymmetric structural design of the present invention, i.e., the input cavity 15 can function as an output cavity and the output cavity 16 can function as an input cavity.

The invention is based on the gap waveguide technology, utilizes a cavity formed by periodically distributing a plurality of metal pins as a resonant cavity, and simultaneously introduces two rows of central resonant columns, can generate a plurality of resonant modes in the resonant cavity, can independently generate two zero points through the interaction between every two different modes, and are respectively positioned at two sides of a pass band. The broadband gap waveguide filter in the embodiment of the invention realizes miniaturization, high performance, low cost and low loss, and is very beneficial to exploring and developing millimeter wave and higher frequency bands for abundant expanded application.

Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other embodiments in the present invention.

The foregoing is considered as illustrative only of the preferred embodiments of the invention and is not to be construed as limiting thereof, the foregoing detailed description being given by way of illustration or explanation of the principles of the invention and not limitation thereof. Various modifications and alterations to the embodiments of the present invention will be apparent to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention. Further, it is intended that the appended claims cover all such variations and modifications as fall within the scope and boundaries of the appended claims or the equivalents of such scope and boundaries.

Claims

1. The utility model provides a millimeter wave high selectivity clearance waveguide filter, its characterized in that includes upper metal cover plate, lower floor's metal flat board, first feed port and second feed port, upper metal cover plate with lower floor's metal flat board passes through the support column to be connected and fixed, first feed port with the second feed port is arranged in two relative sides of lower floor's metal flat board respectively, have on the face of lower floor's metal flat board that is close to upper metal cover plate:

the input cavity and the output cavity are respectively communicated with the first feeding port and the second feeding port;

the metal pins are closely arranged at preset intervals, a rectangular resonant cavity is formed in the center of the lower metal flat plate in a surrounding mode, the resonant cavity is communicated with the input cavity and the output cavity, the height of each metal pin is lower than that of the support column, and an air gap layer between the upper metal cover plate and the upper surface of each metal pin is formed;

the central resonant columns are positioned at the centers of the resonant cavities and are distributed in a centrosymmetric manner;

and the tuning pin is positioned at the position where the input cavity and the output cavity are communicated with the resonant cavity.

2. The millimeter-wave high selectivity gap waveguide filter of claim 1, wherein the support posts are located at four corners of the inner surface of the lower metal plane, the support posts and the lower metal plane being of an integrally formed structure;

the upper-layer metal cover plate further comprises a plurality of screws, and the plurality of screws correspond to the supporting columns respectively and are used for fixing the upper-layer cover plate and the lower-layer metal flat plate.

3. The millimeter-wave high selectivity gap waveguide filter of claim 1, wherein the first and second feed ports use a standard rectangular waveguide port WR-14 for feeding and receiving signals, and have dimensions of 3.759mm in length and 1.88mm in width.

4. The millimeter-wave highly selective gap waveguide filter according to claim 1, wherein the first and second feed ports are arranged in a central symmetry, and the input and output cavities are also arranged in a central symmetry.

5. The millimeter-wave high selectivity gap waveguide filter of claim 1, wherein the central resonator posts are in one or two rows, each row containing 2 or 3 central resonator posts.

6. The millimeter-wave high selectivity gap waveguide filter of claim 1, wherein two of the tuning pins are disposed in a centrosymmetric manner at positions where the resonant cavity communicates with the input cavity and the output cavity, respectively.

7. The millimeter-wave high selectivity gap waveguide filter of claim 1, wherein the input and output cavities are chamfered at corners.

8. The millimeter-wave high selectivity gap waveguide filter of claim 1, wherein the lower metal plane plate and the metal pins, center resonator column, and tuning pins are integrally formed during manufacture.

9. The millimeter-wave highly selective gap waveguide filter according to claim 1, wherein the input cavity, output cavity, and the first and second feed ports are rectangular in shape, and the metal pin, central resonant cylinder, and tuning pin are cylindrical or right quadrangular prism in shape.

10. The millimeter-wave high selectivity gap waveguide filter of claim 1, wherein the metal pins have a height greater than a height of a center resonance post, the height of the center resonance post being greater than a height of the tuning pins.