Multilayer Wide Stopband Substrate Integrated Waveguide Filter

Abstract

The present invention discloses a multi-layer substrate integrated waveguide filter with a wide stopband, which comprises a plurality of successively arranged metal substrates, and a dielectric substrate is arranged between adjacent metal substrates; metallized via hole arrays penetrate through corresponding positions on adjacent metal substrates and the dielectric substrate therebetween to form resonant cavities; the resonant cavities located on the same layer are independently arranged; the resonant cavities located on different layers are staggeredly stacked and connected through a slot array, wherein the slot array is parallel to the magnetic field direction of the main mode of the waveguide filter, and the slot array is arranged at the weakest magnetic field of some high-order modes of the waveguide filter and is perpendicular to the magnetic field direction of some high-order modes of the waveguide filter. The present invention has a sufficient stopband width and is easy to integrate.

Description

Technical Field

[0001] The present invention belongs to the technical field of microwave processing, and particularly relates to a multi-layer wide-stopband substrate integrated waveguide filter. Background Art

[0002] As an important component device in radio frequency and microwave circuit systems, filters have been developing towards the direction of low cost, low power consumption, small size, high power handling capacity, and easy integration. The substrate integrated waveguide filter combines waveguide and planar structures, and has the advantages of small size, low loss, and easy integration with planar circuits.

[0003] Due to the continuous development of modern communication circuit systems, the role of wide-stopband filters in eliminating unwanted clutter and interference signals has always received extensive attention. At present, the wide-stopband filters designed by substrate integrated waveguides have a narrow stopband on the one hand and are not easy to integrate on the other hand. It is difficult to achieve both a wide stopband and easy integration, which greatly limits the application range of wide-stopband substrate integrated waveguide filters.

[0004] To solve the above problems, it is necessary for the filter to have not only a sufficient stopband width, but also a compact structure and easy integration with other microwave circuits. Therefore, there is an urgent need to study wide-stopband filters that are easy to integrate. Summary of the Invention

[0005] In view of the above problems, the present invention proposes a multi-layer wide-stopband substrate integrated waveguide filter, which has a sufficient stopband width and is easy to integrate.

[0006] In order to achieve the above technical objectives and reach the above technical effects, the present invention is realized through the following technical solutions:

[0007] A multi-layer wide-stopband substrate integrated waveguide filter includes a plurality of sequentially arranged metal substrates, and a dielectric substrate is provided between adjacent metal substrates;

[0008] Metalized via arrays penetrate through corresponding positions on adjacent metal substrates and the dielectric substrate therebetween to form resonant cavities;

[0009] The resonant cavities in the same layer are independently arranged;

[0010] The resonant cavities in different layers are staggered and stacked, and are connected by a slot array. Among them, the slot array is parallel to the magnetic field direction of the main mode of the waveguide filter, and the slot array is arranged at the weakest magnetic field of some high-order modes of the waveguide filter and is perpendicular to the magnetic field direction of some high-order modes of the waveguide filter.

[0011] Optionally, the multi-layer wide stopband substrate integrated waveguide filter includes a top metal substrate and a bottom metal substrate which are oppositely arranged, and a first intermediate metal substrate and a second intermediate metal substrate are stacked between the top metal substrate and the bottom metal substrate; dielectric substrates are stacked between adjacent metal substrates;

[0012] The top metal substrate and the first intermediate metal substrate, and at corresponding positions on the dielectric substrate therebetween, a first metallized via hole array and a third metallized via hole array penetrate through, forming a first resonant cavity and a third resonant cavity;

[0013] The bottom metal substrate and the second intermediate metal substrate, and at corresponding positions on the dielectric substrate therebetween, a second metallized via hole array penetrates through, forming a second resonant cavity.

[0014] Optionally, the first resonant cavity, the second resonant cavity and the third resonant cavity are stacked in an interleaved manner, and the second resonant cavity is connected to the first resonant cavity and the third resonant cavity respectively through a slot array.

[0015] Optionally, the multi-layer wide stopband substrate integrated waveguide filter includes a top metal substrate and a bottom metal substrate which are oppositely arranged, and a first intermediate metal substrate and a second intermediate metal substrate are stacked between the top metal substrate and the bottom metal substrate; dielectric substrates are stacked between adjacent metal substrates;

[0016] The top metal substrate and the first intermediate metal substrate, and at corresponding positions on the dielectric substrate therebetween, a first metallized via hole array, a third metallized via hole array and a fifth metallized via hole array penetrate through, forming a first resonant cavity, a third resonant cavity and a fifth resonant cavity;

[0017] The bottom metal substrate and the second intermediate metal substrate, and at corresponding positions on the dielectric substrate therebetween, a second metallized via hole array and a fourth metallized via hole array penetrate through, forming a second resonant cavity and a fourth resonant cavity.

[0018] Optionally, the first resonant cavity, the second resonant cavity, the third resonant cavity, the fourth resonant cavity and the fifth resonant cavity are stacked in an interleaved manner, and the second resonant cavity is connected to the first resonant cavity and the third resonant cavity respectively through a slot array, and the fourth resonant cavity is connected to the third resonant cavity and the fifth resonant cavity respectively through a slot array.

[0019] Optionally, an input port and an output port are provided on the metal substrate at the topmost layer.

[0020] Optionally, the input port is a microstrip line connected to the first resonant cavity, and the output port is a microstrip line connected to the second resonant cavity.

[0021] Optionally, the input port and the output port are centrosymmetric with respect to the center of the filter.

[0022] Optionally, slits are provided at corresponding positions on the sides of the upper and lower resonators close to each other, and all the slits together form a slit array; the position and direction of the slit array should meet the following requirements:

[0023] The slit array is located at the weakest magnetic field of the TE m0n mode where m = 3, 5, 7, …, n = 1, 2, 3, …; perpendicular to the magnetic field of the TE m0n mode where m = 1, 2, 3, …, n = 3, 5, 7, …; and the slit array is parallel to the magnetic field direction of the main mode.

[0024] Optionally, the slit is provided on a metal substrate, and the slit is rectangular.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] The present invention adopts a multi-layer substrate stacking method. The upper and lower metal substrates and the metallized via hole array between the upper and lower metal substrates form a resonator. The upper and lower resonators are stacked staggered and connected through a slit array. The coplanar setting of the input and output ports makes the filter structure more compact and easier to integrate with modern microwave and millimeter-wave circuit systems. Moreover, the provided slit array can well eliminate the coupling of high-order modes while maintaining good coupling of the main mode, achieving the performance of a wide stopband for the filter. Description of the Drawings

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings, where:

[0028] Figure 1 It is a three-dimensional structure diagram of a third-order multi-layer wide stopband substrate integrated waveguide filter;

[0029] Figure 2 It is Figure 1 the top view of the filter shown;

[0030] Figure 3 It is Figure 1 the passband S-parameter diagram of the filter shown;

[0031] Figure 4 It is Figure 1 the out-of-band S-parameter diagram of the filter shown;

[0032] Figure 5It is a three-dimensional structure diagram of a fifth-order multi-layer wide-stopband substrate integrated waveguide filter;

[0033] Figure 6 It is Figure 5 the top view of the filter shown;

[0034] Figure 7 It is Figure 5 the passband S-parameter diagram of the filter shown;

[0035] Figure 8 It is Figure 5 the out-of-band S-parameter diagram of the filter shown. Specific embodiments

[0036] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way limits the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0037] Unless otherwise specifically stated, the relative arrangements, numerical expressions and values of the components and steps described in these embodiments do not limit the scope of the present invention. At the same time, it should be understood that for the sake of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationship. Technologies, methods and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods and devices should be regarded as part of the authorization specification. In all the examples shown and discussed here, any specific value should be interpreted as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may also include different values. It should be noted that: similar reference numerals and letters indicate similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0038] In the description of the present invention, the meaning of several is more than one, and the meaning of multiple is more than two. Understandings such as greater than, less than, exceeding, etc. do not include the present number, and understandings such as above, below, within, etc. include the present number. If there is a description of first and second, it is only for the purpose of distinguishing technical features and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence relationship of the indicated technical features.

[0039] In the description of the present invention, the description with reference to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0040] The application principle of the present invention will be described in detail below with reference to the accompanying drawings.

[0041] The present invention provides a multi-layer wide-stopband substrate integrated waveguide filter, which includes a plurality of sequentially arranged metal substrates, and dielectric substrates are provided between adjacent metal substrates;

[0042] Metalized via hole arrays 9 penetrate through corresponding positions on adjacent metal substrates and the dielectric substrates therebetween to form resonant cavities;

[0043] The resonant cavities located on the same layer are independently arranged;

[0044] The resonant cavities located on different layers are stacked in an interleaved manner and are connected by a slot array 10. Among them, the slot array 10 is parallel to the magnetic field direction of the main mode of the waveguide filter, and the slot array 10 is arranged at the weakest magnetic field of some high-order modes of the waveguide filter and is perpendicular to the magnetic field direction of some high-order modes of the waveguide filter.

[0045] The substrate integrated waveguide filter of the present invention adopts a multi-layer structure. Compared with the traditional single-layer structure, the structure is more compact. Compared with other multi-layer structures, only two dielectric substrates are used, and the ports are located in the same plane, which is more suitable for integration with modern microwave and millimeter-wave circuit systems; at the same time, a vertically stacked magnetic coupling method is adopted, and the coupling level of the filter can be flexibly adjusted as needed. On the premise of ensuring the performance of the substrate integrated waveguide remains unchanged, it has an ultra-wide stopband that other substrate integrated waveguide filters in the past did not have, and at the same time, it can also maintain a good out-of-band rejection level.

[0046] In a specific embodiment of the present invention, the multi-layer wide-stopband substrate integrated waveguide filter includes a top metal substrate 3 and a bottom metal substrate 6 arranged opposite to each other. A first intermediate metal substrate 4 and a second intermediate metal substrate 5 are stacked between the top metal substrate 3 and the bottom metal substrate 6; dielectric substrates are stacked between adjacent metal substrates;

[0047] The top metal substrate 3 and the first middle metal substrate 4, as well as the dielectric substrate therebetween, are penetrated by metallized through hole arrays 9 at corresponding positions, which are respectively recorded as the first metallized through hole array and the third metallized through hole array, forming the first resonant cavity and the third resonant cavity;

[0048] The bottom metal substrate 6, the second middle metal substrate 5, and the corresponding positions on the dielectric substrate therebetween are all penetrated by a metallized through hole array 9, which is denoted as a second metallized through hole array, forming a second resonant cavity.

[0049] The first resonant cavity, the second resonant cavity and the third resonant cavity are stacked alternately, and the second resonant cavity is connected to the first resonant cavity and the third resonant cavity respectively through the slot array 10.

[0050] In another specific embodiment of the present invention, the multilayer wide stopband substrate integrated waveguide filter comprises a top metal substrate 3 and a bottom metal substrate 6 which are arranged opposite to each other, a first intermediate metal substrate 4 and a second intermediate metal substrate 5 are stacked between the top metal substrate 3 and the bottom metal substrate 6; a dielectric substrate is stacked between adjacent metal substrates;

[0051] The top metal substrate 3 and the first middle metal substrate 4, as well as the corresponding positions on the dielectric substrate therebetween, are penetrated by metallized through hole arrays 9, which are respectively denoted as the first metallized through hole array, the third metallized through hole array and the fifth metallized through hole array, forming the first resonant cavity, the third resonant cavity and the fifth resonant cavity;

[0052] The bottom metal substrate 6, the second middle metal substrate 5, and the corresponding positions on the dielectric substrate therebetween are penetrated by metallized through hole arrays 9, which are respectively recorded as the second metallized through hole array and the fourth metallized through hole array, forming the second resonant cavity and the fourth resonant cavity.

[0053] Among them, the first resonant cavity, the second resonant cavity, the third resonant cavity, the fourth resonant cavity and the fifth resonant cavity are stacked alternately, and the second resonant cavity is connected to the first resonant cavity and the third resonant cavity respectively through the slot array 10, and the fourth resonant cavity is connected to the third resonant cavity and the fifth resonant cavity respectively through the slot array 10.

[0054] In a specific embodiment of the present invention, an input port 1 and an output port 2 are provided on the topmost metal substrate. In a specific implementation, the input port 1 is a microstrip line connected to the first resonant cavity, and the output port 2 is a microstrip line connected to the third resonant cavity. Preferably, the input port 1 and the output port 2 are symmetrical about the center of the filter.

[0055] In a specific embodiment of the present invention, gaps are provided at corresponding positions on the sides of the upper and lower resonant cavities that are close to each other, and all the gaps together form a gap array 10. In the specific implementation process, the gaps are provided on a metal substrate, and the gaps are rectangular.

[0056] The multi-layer wide-stopband substrate integrated waveguide bandpass filter in the present invention will be described in detail below in conjunction with specific embodiments.

[0057] The multi-layer wide-stopband substrate integrated waveguide bandpass filter in the embodiment of the present invention includes a stacked top metal substrate 3 and a bottom metal substrate 6. An input port 1 and an output port 2 are provided on the top metal substrate 3. Two intermediate metal substrates are stacked between the top metal substrate 3 and the bottom metal substrate 6, which are respectively denoted as the first intermediate metal substrate 4 and the second intermediate metal substrate 5. Dielectric substrates are stacked between adjacent upper and lower metal substrates.

[0058] The input port 1 is a microstrip line connected to the resonant cavity R1, and the output port 2 is a microstrip line connected to the resonant cavity R3. The input port 1 and the output port 2 are centrosymmetric about the center of the filter.

[0059] A metallized via array 9 penetrates through the adjacent metal substrates and the dielectric substrate therebetween. The metallized via array 9 penetrating through the dielectric substrate, the upper metal substrate, and the lower metal substrate together form a resonant cavity.

[0060] The upper and lower resonant cavities are stacked in an interleaved manner. A plurality of gap arrays 10 connecting the upper and lower resonant cavities are etched on the first intermediate metal substrate 4 and the second intermediate metal substrate 5 respectively. The gap array 10 includes a plurality of rectangular gaps, and all the gaps are distributed on a group of side walls of the resonant cavity.

[0061] The gap arrays 10 on the first intermediate metal substrate 4 and the second intermediate metal substrate 5 are parallel to the two side walls of the resonant cavity and are symmetric about a center line of the resonant cavity.

[0062] The position and direction of the gap array 10 have the following requirements: The gap array 10 is located at the weakest magnetic field of some high-order modes and is perpendicular to the magnetic field of another part of the high-order modes. The gap array 10 is parallel to the magnetic field direction of the main mode. That is, the position and direction of the gap array should meet the following requirements: The gap array is located at the weakest magnetic field of the TE m0n mode, where m = 3, 5, 7, …, n = 1, 2, 3, …; perpendicular to the magnetic field of the TE m0n mode, where m = 1, 2, 3, …, n = 3, 5, 7, …; and the gap array is parallel to the magnetic field direction of the main mode.

[0063] The main mode magnetic coupling is performed by using the gap array 10, and the electric coupling between modes can be ignored. Therefore, only the magnetic coupling of high-order modes needs to be considered for suppression.

[0064] The slot array 10 perpendicular to a part of the high-order mode magnetic field is translated along the magnetic field direction of the high-order mode, and the suppression of the mode is hardly affected. When it is translated to another area where the high-order mode magnetic field is the weakest, the out-of-band suppression effect can reach the optimal.

[0065] Since the weakest magnetic field is an area, adjusting the length of the slot array 10 in a suitable area hardly affects the mode suppression, which is beneficial to flexibly regulating the coupling of the main mode.

[0066] For each pair of orthogonally distributed high-order modes, by arranging the slot array 10 at the weakest magnetic field of one of the modes, and exactly the slot array 10 is perpendicular to the magnetic field of another high-order mode. Therefore, such a setting can suppress multiple high-order modes simultaneously. These slot arrays 10 are also parallel to the magnetic field of the main mode, enabling the main mode to complete magnetic coupling, so that the effect of a wide stopband can be achieved while coupling the main mode.

[0067] In the specific implementation process, the dielectric substrate can be selected as Rogers 5880 dielectric board, where the dielectric constant is 2.2 and the thickness is 0.508 mm.

[0068] The multi-layer wide-stopband substrate integrated waveguide filter in the embodiment of the present invention adopts a multi-layer substrate stacking method. The upper and lower two resonators are staggered and stacked and connected through the slot array 10 on the middle metal substrate. This not only reduces the number of dielectric substrates but also maintains the coplanar setting of the ports, making it easier to integrate with modern microwave and millimeter-wave circuit systems. And the set slot array can, while maintaining good coupling of the main mode, also well eliminate the coupling of high-order modes, achieving the wide-stopband characteristic of the filter.

[0069] To reflect the effect of the filter, a third-order and fifth-order easily integrated multi-layer wide-stopband substrate integrated waveguide filter is constructed in the embodiment of the present invention, and the center frequency of the filter is 6 GHz.

[0070] Figure 1 The third-order easily integrated multi-layer wide-stopband substrate integrated waveguide filter includes a top metal substrate 3, an upper dielectric substrate 7, a first intermediate metal substrate 4, a second intermediate metal substrate 5, a lower dielectric substrate 8, and a bottom metal substrate 6 stacked in sequence. All the through holes in all the metallized via hole arrays 9 of the filter have the same size.

[0071] The top metal substrate 3, the first intermediate metal substrate 4, and the metallized via hole array 9 therebetween form the first resonator R1 and the third resonator R3; the second intermediate metal substrate 5, the bottom metal substrate 6, and the metallized via hole array 9 therebetween form the second resonator R2.

[0072] AsFigure 1 and 2 As shown, multiple groups of slot arrays 10 are etched on the first intermediate metal substrate 4 and the second intermediate metal substrate 5, and are symmetric about the vertical center line of the top view of the resonant cavity. Figure 4 The slot 10 connecting the resonant cavity R1 and the resonant cavity R2 is perpendicular to the magnetic field of the TE m0n (n is an even number) mode and is located at the weakest point of the magnetic field of the TE 501 mode. Therefore, the coupling of these modes can be suppressed. The slot 10 connecting the resonant cavity R2 and the resonant cavity R3 is perpendicular to the magnetic fields of the TE m03 mode and the TE 105 mode and is located at the weakest point of the magnetic field of the TE 30n mode. Therefore, the coupling of these modes can also be suppressed. In addition, since the TE m0n (n is an even number) mode is fed at the center, it will not be excited. Therefore, the third-order filter operating in the TE 101 mode can suppress all high-order modes within the TE 404 , and the stopband may extend to 4f0 (f0: the center frequency of the filter).

[0073] An input port 1 and an output port 2 are respectively arranged on the top metal substrate 3. The input port 1 and the output port 2 both use microstrip lines with the same size, and the two ports are symmetric about the center of the filter.

[0074] Figure 3 is the passband S-parameter curve of the third-order filter. It can be clearly seen that the passband transmission performance is good, and the in-band return loss S11 is all below -20 dB.

[0075] Figure 4 is the out-of-band S-parameter curve of the third-order filter. The stopband suppression of -30 dB can extend to 3.97f0.

[0076] Figure 5 A fifth-order easily integrated multi-layer wide-stopband substrate integrated waveguide filter includes a top metal substrate 3, an upper dielectric substrate 7, a first intermediate metal substrate 4, a second intermediate metal substrate 5, a lower dielectric substrate 8, and a bottom metal substrate 6 stacked in sequence. All the through holes in all the metallized via arrays 9 of the filter have the same size.

[0077] The top metal substrate 3, the first intermediate metal substrate 4, and the metallized via array 9 therebetween form the first resonant cavity R1, the third resonant cavity R3, and the fifth resonant cavity R5. The second intermediate metal substrate 5, the bottom metal substrate 6, and the metallized via array 9 therebetween form the second resonant cavity R2 and the fourth resonant cavity R4.

[0078] As Figure 5 and 6As shown, multiple sets of slot arrays 10 are etched on the first intermediate metal substrate 4 and the second intermediate metal substrate 5, symmetric about the horizontal center line in the top view of the resonant cavity. Figure 6 The slot 10 connecting the resonant cavity R1 and the resonant cavity R2 is perpendicular to the magnetic field of the TE m0n (n is an even number) mode, so the coupling of these modes can be suppressed. The slot 10 connecting the resonant cavity R2 and the resonant cavity R3 is perpendicular to the magnetic field of the TE m03 mode and is located at the weakest point of the magnetic field of the TE 30n mode, so the coupling of these modes can be suppressed. The slot 10 connecting the resonant cavity R3 and the resonant cavity R4 is perpendicular to the magnetic field of the TE m05 mode and is located at the weakest point of the magnetic field of the TE 50n mode, so the coupling of these modes can be suppressed; the slot 10 connecting the resonant cavity R4 and the resonant cavity R5 is perpendicular to the magnetic field of the TE m07 mode and is located at the weakest point of the magnetic field of the TE 70n mode, so the coupling of these modes can also be suppressed; in addition, since the TE m0n (m is an even number) mode is fed at the center, it will not be excited. Therefore, the fifth-order filter operating in the TE 101 can suppress all high-order modes within the TE 707 , and the stopband may extend to 7f0.

[0079] An input port 1 and an output port 2 are respectively arranged on the top metal substrate 3. Both the input port 1 and the output port 2 use microstrip lines with the same size, and the two ports are symmetric about the center of the filter.

[0080] Figure 7 is the passband S-parameter curve of the fifth-order filter. It can be clearly seen that the passband transmission performance is good, and the in-band return loss S11 is all below -20 dB.

[0081] Figure 8 is the out-of-band S-parameter curve of the fifth-order filter. The stopband suppression level of nearly -36 dB can extend to 6.5f0.

[0082] In the description of this application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the protection content of the present invention.

[0083] The foregoing has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and what is described in the above embodiments and the specification is only to illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements fall within the scope of the present invention claimed. The scope of the present invention claimed is defined by the appended claims and their equivalents.

Claims

1. A multi-layer substrate integrated waveguide filter with a wide stopband, characterized in that: It includes a plurality of successively arranged metal substrates, and dielectric substrates are provided between adjacent metal substrates; Metalized vias arrays penetrate through corresponding positions on adjacent metal substrates and the dielectric substrates therebetween, forming resonant cavities; The resonant cavities located on the same layer are independently arranged; The resonant cavities located on different layers are staggeredly stacked and connected through a slot array, wherein the slot array is parallel to the magnetic field direction of the main mode of the waveguide filter, and the slot array is arranged at the weakest magnetic field of some high-order modes of the waveguide filter and perpendicular to the magnetic field direction of some high-order modes of the waveguide filter; An input port and an output port are provided on the metal substrate at the topmost layer; Slots are provided at corresponding positions on the adjacent sides of the upper and lower resonant cavities close to each other, and all the slots together form a slot array; the position and direction of the slot array should meet the following requirements: The slot array is located at the weakest magnetic field of the TE m0n mode, where m = 3, 5, 7, … and n = 1, 2, 3, …; perpendicular to the magnetic field of the TE m0n mode, where m = 1, 2, 3, … and n = 3, 5, 7, …; and the slot array is parallel to the magnetic field direction of the dominant mode; The slots are provided on the metal substrate, and the slots are rectangular.

2. The multilayer wide stopband substrate integrated waveguide filter according to claim 1, wherein: The multi-layer wide-stopband substrate integrated waveguide filter includes a top-layer metal substrate and a bottom-layer metal substrate arranged oppositely, and a first intermediate metal substrate and a second intermediate metal substrate are stacked between the top-layer metal substrate and the bottom-layer metal substrate; Dielectric substrates are stacked between adjacent metal substrates; First metalized vias arrays and third metalized vias arrays penetrate through corresponding positions on the top-layer metal substrate and the first intermediate metal substrate and the dielectric substrates therebetween, forming a first resonant cavity and a third resonant cavity; Second metalized vias arrays penetrate through corresponding positions on the bottom-layer metal substrate and the second intermediate metal substrate and the dielectric substrates therebetween, forming a second resonant cavity.

3. The multilayer wide stopband substrate integrated waveguide filter according to claim 2, characterized in that: The first resonant cavity, the second resonant cavity and the third resonant cavity are staggeredly stacked, and the second resonant cavity is connected to the first resonant cavity and the third resonant cavity respectively through a slot array.

4. A multi-layer wide stopband substrate integrated waveguide filter according to claim 1, wherein: The multi-layer wide-stopband substrate integrated waveguide filter includes a top-layer metal substrate and a bottom-layer metal substrate arranged oppositely, and a first intermediate metal substrate and a second intermediate metal substrate are stacked between the top-layer metal substrate and the bottom-layer metal substrate; Dielectric substrates are stacked between adjacent metal substrates; First metalized vias arrays, third metalized vias arrays and fifth metalized vias arrays penetrate through corresponding positions on the top-layer metal substrate and the first intermediate metal substrate and the dielectric substrates therebetween, forming a first resonant cavity, a third resonant cavity and a fifth resonant cavity; Second metalized vias arrays and fourth metalized vias arrays penetrate through corresponding positions on the bottom-layer metal substrate and the second intermediate metal substrate and the dielectric substrates therebetween, forming a second resonant cavity and a fourth resonant cavity.

5. A multi-layer wide stopband substrate integrated waveguide filter according to claim 4, characterized in that: The first resonant cavity, the second resonant cavity, the third resonant cavity, the fourth resonant cavity and the fifth resonant cavity are staggeredly stacked, and the second resonant cavity is connected to the first resonant cavity and the third resonant cavity respectively through a slot array, and the fourth resonant cavity is connected to the third resonant cavity and the fifth resonant cavity respectively through a slot array.

6. The multi-layer wide-stopband substrate integrated waveguide filter according to claim 1, characterized in that: The input port is a microstrip line connected to the first resonant cavity, and the output port is a microstrip line connected to the third resonant cavity.

7. A multi-layer wide-stopband substrate integrated waveguide filter according to claim 1, wherein: The input port and the output port are centrosymmetric about the filter center.

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