A multi-zero bandpass filter

Abstract

The present application provides a multi-zero-point bandpass filter, which includes a dielectric substrate and at least two resonators connected to the dielectric substrate, the dielectric substrate includes an input end, an output end and a ground end, the input side of some of the at least two resonators is connected to the input end, the output side of another part of the resonators is connected to the output end, and the ground sides of at least two resonators are connected to the ground end; at least two resonators are stacked and arranged at intervals, and the odd mode and even mode generated by one resonator are respectively coupled with the odd mode and even mode generated by another adjacent resonator, generating four signal transmission paths and three transmission zero points. The multi-zero-point bandpass filter provided by the present application can generate mixed cross-coupling between odd and even modes between different resonators, thereby providing multiple transmission paths for radio frequency signals, and then generating multiple transmission zero points, improving the filter band selectivity, and the stacking arrangement between resonators also improves the compactness of the filter and reduces the physical size.

Description

Technical Field

[0001] The present application relates to the technical field of radio frequency filters, and in particular to a multi-zero-point bandpass filter. Background Art

[0002] In order to adapt to the rapid development of modern communication systems, RF filters need to be improved in terms of physical size and frequency selectivity. Existing studies using quarter-wavelength resonators or step impedance resonance methods are limited to planar structures and have limited size reduction. For selectivity, traditional single-mode resonators have high requirements on the number of resonators and topological structures to achieve cross-coupling, and the number of transmission zeros is limited.

[0003] Therefore, the use of traditional filter technology to design compact and highly selective bandpass filters can no longer fully meet the requirements of technological development, and a miniaturized multi-zero bandpass filter is urgently needed to solve the above problems. Summary of the invention

[0004] The purpose of the present application is to provide a multi-zero bandpass filter to solve the problems of the limited degree of size reduction of the traditional resonator and the limited number of transmission zeros in the above-mentioned prior art.

[0005] The present application provides a multi-zero-point bandpass filter, which includes: a dielectric substrate and at least two resonators connected to the dielectric substrate, the dielectric substrate includes an input end, an output end and a ground end, the input side of some resonators of the at least two resonators is connected to the input end, the output side of another part of the resonators is connected to the output end, and the ground sides of the at least two resonators are both connected to the ground end;

[0006] The at least two resonators are stacked and arranged at intervals, and the odd mode and even mode generated by one resonator are respectively coupled with the odd mode and even mode generated by another adjacent resonator, thereby generating four signal transmission paths and three transmission zero points.

[0007] In one possible design, the number of the resonators is two, namely a first-order resonator and a second-order resonator. The input side of the first-order resonator is connected to the input end, the output side of the second-order resonator is connected to the output end, and the ground sides of the first-order resonator and the second-order resonator are both connected to the ground end.

[0008] In a possible design, the first-order resonator and the second-order resonator are buried in the dielectric matrix.

[0009] In a possible design, projections of the first-order resonator and the second-order resonator partially overlap.

[0010] In a possible design, the first-order resonator and the second-order resonator have the same structure, and both the first-order resonator and the second-order resonator include a main resonant pole, an upper compensation pole and a lower compensation pole, the upper compensation pole and the lower compensation pole are respectively located on both sides of the main resonant pole, and the upper compensation pole, the main resonant pole and the lower compensation pole are stacked and arranged at intervals;

[0011] The main resonance pole of the first-order resonator is connected to the input end;

[0012] The main resonance pole of the second-order resonator is connected to the output end.

[0013] In a possible design, the main resonant pole includes a first branch, a second branch and a third branch, the second branch is located between the first branch and the third branch, and the length of the second branch is longer than the first branch and the second branch.

[0014] In a possible design, the upper compensation pole includes a first compensation pole, a second compensation pole and a third compensation pole, and the lower compensation pole includes a fourth compensation pole, a fifth compensation pole and a sixth compensation pole;

[0015] The first compensation pole and the fourth compensation pole are respectively located on both sides of the first branch node, and the first compensation pole, the first branch node and the fourth compensation pole are stacked and arranged at intervals;

[0016] The second compensation pole and the fifth compensation pole are respectively located on both sides of the second branch node, and the second compensation pole, the second branch node and the fifth compensation pole are stacked and arranged at intervals;

[0017] The third compensation pole and the sixth compensation pole are respectively located on both sides of the third branch node, and the third compensation pole, the third branch node and the sixth compensation pole are stacked and arranged at intervals;

[0018] The first compensation pole, the second compensation pole, the third compensation pole, the fourth compensation pole, the fifth compensation pole and the sixth compensation pole each include a first end and a second end, the first ends of the first compensation pole, the second compensation pole, the third compensation pole, the fourth compensation pole, the fifth compensation pole and the sixth compensation pole are each connected to the ground end, and the second ends of the first compensation pole, the second compensation pole, the third compensation pole, the fourth compensation pole, the fifth compensation pole and the sixth compensation pole are each suspended.

[0019] In one possible design, the multi-zero-point bandpass filter also includes a first conductor, a second conductor, an input tap and an output tap, the first conductor and the second conductor are respectively attached to both sides of the dielectric substrate, the first conductor forms the input end, the second conductor forms the output end, the first-order resonator is connected to the first conductor through the input tap, and the second-order resonator is connected to the second conductor through the output tap.

[0020] In a possible design, the multi-zero-point bandpass filter further includes a first floor and a second floor, wherein the first floor and the second floor are respectively attached to two sides of the dielectric substrate that are adjacent to and opposite to the first conductor and the second conductor;

[0021] The first compensation pole, the second compensation pole, the third compensation pole, the fourth compensation pole, the fifth compensation pole and the sixth compensation pole of the first-order resonator are all connected to the first ground plane;

[0022] The first compensation pole, the second compensation pole, the third compensation pole, the fourth compensation pole, the fifth compensation pole and the sixth compensation pole of the second-order resonator are all connected to the second ground plane.

[0023] In one possible design, the multi-zero-point bandpass filter also includes a first shielding plate and a second shielding plate, and the first shielding plate and the second shielding plate are respectively attached to the two sides of the dielectric substrate that are adjacent to and opposite to the first conductor, the second conductor, the first floor, and the second floor.

[0024] In a possible design, notches are provided on the edges of the first shielding plate and the second shielding plate that are adjacent to the input end and the output end.

[0025] In a possible design, edges of the first shielding plate and the second shielding plate adjacent to the first floor panel and the second floor panel are provided with empty grooves.

[0026] The technical solution provided by this application can achieve the following beneficial effects:

[0027] The multi-zero-point bandpass filter provided by the present application can generate mixed cross-coupling between the odd and even modes of different resonators by stacking and arranging at least two resonators in a single direction, that is, the odd mode of one resonator can be coupled with the odd mode and even mode of another resonator, and the even mode of one resonator can also be coupled with the odd mode and even mode of another resonator, thereby providing multiple transmission paths for radio frequency signals and generating multiple transmission zeros, thereby improving the filter band selectivity and making the filter have good passband response and double-sideband suppression characteristics, which is very suitable for modern radio frequency communication systems, and the stacking arrangement between resonators also improves the compactness of the filter and reduces the physical size.

[0028] It should be understood that the foregoing general description and the following detailed description are exemplary only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic diagram of the structure of a multi-zero bandpass filter provided in an embodiment of the present application;

[0030] Figure 2 A topological structure diagram of a multi-zero bandpass filter provided in an embodiment of the present application;

[0031] Figure 3 A simulation result diagram of a multi-zero bandpass filter provided in an embodiment of the present application (S11 and S21 curve diagrams);

[0032] Figure 4 is a schematic diagram of the structure of the first-order resonator;

[0033] Figure 5 is a schematic diagram of the structure of the main resonant pole;

[0034] Figure 6 is a structural schematic diagram of the upper compensation pole;

[0035] Figure 7 A side view showing the arrangement of the upper compensation pole, the main resonance pole and the lower compensation pole;

[0036] Figure 8 is a schematic structural diagram of a first conductor;

[0037] Fig. 9 is a structural schematic diagram of the first floor;

[0038] Fig.10 Schematic diagram of the structure of the first shielding plate.

[0039] Reference numerals:

[0040] 1- medium matrix;

[0041] 2- First order resonator;

[0042] 21- main resonant pole;

[0043] 211-First branch;

[0044] 212-Second branch;

[0045] 213-third branch;

[0046] 22-upper compensation pole;

[0047] 221- first compensation pole;

[0048] 222- second compensation pole;

[0049] 223-third compensation pole;

[0050] 23-lower compensation pole;

[0051] 231- fourth compensation pole;

[0052] 232-fifth compensation pole;

[0053] 233-sixth compensation pole;

[0054] 3- Second order resonator;

[0055] 4- a first electrical conductor;

[0056] 41- input tap;

[0057] 5- a second conductor;

[0058] 51- output tap;

[0059] 6- First floor;

[0060] 7- Second floor;

[0061] 8- first shielding plate;

[0062] 81-Gap;

[0063] 82 - empty slot;

[0064] 9- Second shielding plate.

[0065] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application. DETAILED DESCRIPTION

[0066] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described here are only used to explain the present application and are not used to limit the present application.

[0067] In the description of this application, unless otherwise clearly specified and limited, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance; unless otherwise specified or explained, the term "plurality" refers to two or more; the terms "connected" and "fixed" should be understood in a broad sense, for example, "connected" can be a fixed connection, a detachable connection, an integral connection, or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0068] Existing quarter-wavelength resonators or methods using step impedance resonance are limited to planar structures. Since their size is directly related to the wavelength, they have great limitations in size reduction and are not conducive to application scenarios with small layout space. In terms of band selectivity, traditional single-mode resonators have high requirements on the number of resonators and topological structures to achieve cross-coupling, that is, there are great restrictions in terms of the number of layouts and layout space, and the number of transmission zeros is limited. Therefore, the use of traditional filter technology to design compact and highly selective bandpass filters can no longer fully meet the requirements of technological development.

[0069] Figure 1 A schematic diagram of the structure of a multi-zero bandpass filter provided in an embodiment of the present application is shown in FIG. Figure 1 As shown, the present application provides a multi-zero-point bandpass filter, which includes a dielectric substrate 1 and at least two resonators connected to the dielectric substrate 1, and the dielectric substrate 1 includes an input end, an output end and a ground end. The input end and the output end are arranged on the outer surface of the dielectric substrate 1, and are used to connect to external electronic devices or circuits. The input side of some of the at least two resonators is connected to the input end, the output side of the other part of the resonators is connected to the output end, and the ground sides of at least two resonators are both connected to the ground end.

[0070] Among them, at least two resonators are stacked and arranged at intervals, and the odd mode and even mode generated by one resonator are coupled with the odd mode and even mode generated by another adjacent resonator, respectively, to generate four signal transmission paths and three transmission zeros. By stacking and arranging at least two resonators in a single direction, the odd and even modes between different resonators can generate mixed cross-coupling, that is, the odd mode of one resonator can be coupled with the odd mode and even mode of another resonator, and the even mode of one resonator can also be coupled with the odd mode and even mode of another resonator, thereby providing multiple transmission paths for RF signals, and then generating multiple transmission zeros, improving the filter band selectivity, and making the filter have good passband response and double-sideband suppression characteristics, which is very suitable for modern RF communication systems, and the stacking arrangement between resonators also improves the compactness of the filter and reduces the physical size.

[0071] Specifically, Figure 1 As shown, in this embodiment, the number of resonators is two, namely a first-order resonator 2 and a second-order resonator 3. The input side of the first-order resonator 2 is connected to the input end, the output side of the second-order resonator 3 is connected to the output end, and the grounding sides of the first-order resonator 2 and the second-order resonator 3 are both connected to the grounding end.

[0072] Figure 2 The topological structure diagram of the multi-zero bandpass filter provided in the embodiment of the present application is as follows: Figure 2 As shown, S represents the source, L represents the load, 1E represents the even mode of the first-order resonator 2, 1O represents the odd mode of the first-order resonator 2, 2E represents the even mode of the second-order resonator 3, and 2O represents the odd mode of the second-order resonator 3. According to the resonator coupling theory, except for the coupling between the odd and even modes in the same resonator, in this embodiment, there is energy coupling between 1E-2E, 1E-2O, 1O-2O and 2O-1E, that is, there are four signal transmission paths between the source and the load, which can generate three transmission zeros. In addition, since the dual-mode resonator has a zero point in the high frequency band, the filter provided in this embodiment has a total of four transmission zeros in the stop band.

[0073] Figure 3 The simulation result diagram of the multi-zero bandpass filter provided in the embodiment of the present application includes S11 curve a and S12 curve b. S11 curve a is the return loss curve on the spectrum, and S21 curve b is the insertion loss curve on the spectrum. Figure 3 As shown in the figure, the center frequency of the filter is 2.63GHz, the 1dB bandwidth is 220MHz, the insertion loss is as low as 0.87dB, the return loss in the passband is better than 20dB, and a transmission zero is generated at each of the 2.44GHz, 2.83GHz, 3.03GHz and 3.28GHz frequencies, ensuring good sideband and stopband suppression characteristics of the bandpass filter.

[0074] Specifically, the first-order resonator 2 and the second-order resonator 3 are both embedded in the dielectric matrix 1, which is beneficial to reducing the volume of the filter, eliminating the adverse effects of environmental factors on the resonator, and improving the reliability of use. The material of the dielectric matrix 1 can be a ceramic material or a high molecular polymer. In this embodiment, the dielectric matrix 1 is preferably made of ceramic material and is prepared using low temperature co-fired ceramic technology.

[0075] Among them, the projections of the first-order resonator 2 and the second-order resonator 3 partially overlap. In a single direction, the first-order resonator 2 and the second-order resonator 3 are arranged in parallel, and the first-order resonator 2 and the second-order resonator 3 are not completely aligned, but there is a partial overlapping area in the projection, realizing a positional "misalignment", so that cross-coupling between the first-order resonator 2 and the second-order resonator 3 can be achieved to generate multiple transmission zeros. The filter in this embodiment can generate four transmission zeros.

[0076] Specifically, Figure 1 and Figure 4 As shown, the first-order resonator 2 and the second-order resonator 3 have the same structure. Figures 4 to 7 The first-order resonator 2 and the second-order resonator 3 shown in the figure both include a main resonant pole 21, an upper compensation pole 22 and a lower compensation pole 23, the upper compensation pole 22 and the lower compensation pole 23 are respectively located on both sides of the main resonant pole 21, and the upper compensation pole 22, the main resonant pole 21 and the lower compensation pole 23 are stacked and arranged at intervals, the main resonant pole 21 of the first-order resonator 2 is connected to the input end, and the main resonant pole 21 of the second-order resonator 3 is connected to the output end.

[0077] Among them, Figure 5 and Figure 6 As shown, the main resonant pole 21 and the upper compensation pole 22 can both be thin metallized structures, and the lower compensation pole 23 and the upper compensation pole 22 can have the same structure, both of which are metallized structures. Figure 7 As shown, the upper compensation pole 22 and the lower compensation pole 23 are respectively located on both sides of the main resonance pole 21, and one end of the upper compensation pole 22 and the lower compensation pole 23 are connected to the grounding end of the dielectric substrate 1 to achieve grounding, and the other ends of the upper compensation pole 22 and the lower compensation pole 23 are suspended, and a certain interval is maintained between the whole and the main resonance pole 21 to achieve coupling connection with the main resonance pole 21. The upper compensation pole 22 and the lower compensation pole 23 can introduce strong electric field coupling to generate a capacitive effect loaded on the main resonance pole 21, which greatly reduces the physical size of the resonator.

[0078] Specifically, Figure 5 As shown, the main resonant pole 21 includes a first branch 211, a second branch 212 and a third branch 213, the second branch 212 is located between the first branch 211 and the third branch 213, and the length of the second branch 212 is longer than the first branch 211 and the second branch 212. The main resonant pole 21 is formed of the first branch 211, the second branch 212 and the third branch 213 to form a "mountain" shape, and the main resonant pole formed by the first branch 211, the second branch 212 and the third branch 213 can make each resonator generate an odd-even dual mode, and make the odd-even dual modes between different resonators generate hybrid cross-coupling, provide multiple transmission paths for radio frequency signals, and then generate transmission zero points, thereby improving the frequency selectivity of the filter.

[0079] Specifically, Figure 5 As shown, the upper compensation pole 22 includes a first compensation pole 221, a second compensation pole 222 and a third compensation pole 223, and the lower compensation pole 23 includes a fourth compensation pole 231, a fifth compensation pole 232 and a sixth compensation pole 233. The first compensation pole 221, the second compensation pole 222, the third compensation pole 223, the fourth compensation pole 231, the fifth compensation pole 232 and the sixth compensation pole 233 can all be metallized sheet structures, such as copper sheets, and the sizes of the compensation poles can be the same. Of course, the sizes of the compensation poles can also be different depending on the specific application.

[0080] Among them, the first compensation pole 221 and the fourth compensation pole 231 are respectively located on both sides of the first branch 211, and the first compensation pole 221, the first branch 211 and the fourth compensation pole 231 are stacked and arranged at intervals. The second compensation pole 222 and the fifth compensation pole 232 are respectively located on both sides of the second branch 212, and the second compensation pole 222, the second branch 212 and the fifth compensation pole 232 are stacked and arranged at intervals. The third compensation pole 223 and the sixth compensation pole 233 are respectively located on both sides of the third branch 213, and the third compensation pole 223, the third branch 213 and the sixth compensation pole 233 are stacked and arranged at intervals. In other words, a compensation pole is arranged on both sides of each branch, and the compensation poles on both sides of each branch keep a certain distance from the branch, forming a stacked and spaced arrangement, so that the strong electric field coupling can be introduced through the compensation poles on both sides of each branch to generate a capacitance effect loaded on the main resonant pole 21, which is conducive to compressing the overall size of the filter.

[0081] Among them, the first compensation pole 221, the second compensation pole 222, the third compensation pole 223, the fourth compensation pole 231, the fifth compensation pole 232 and the sixth compensation pole 233 all include a first end and a second end, and the first ends of the first compensation pole 221, the second compensation pole 222, the third compensation pole 223, the fourth compensation pole 231, the fifth compensation pole 232 and the sixth compensation pole 233 are all connected to the grounding end of the dielectric substrate 1, and the second ends of the first compensation pole 221, the second compensation pole 222, the third compensation pole 223, the fourth compensation pole 231, the fifth compensation pole 232 and the sixth compensation pole 233 are all suspended, that is, a distance is maintained between the corresponding branches.

[0082] As a specific implementation method, Figure 1 and Figure 8 As shown, the multi-zero-point bandpass filter also includes a first conductor 4, a second conductor, an input tap 41 and an output tap 51. The first conductor 4 and the second conductor are respectively attached to the two sides of the dielectric substrate 1, the first conductor 4 forms an input end, the second conductor forms an output end, the first-order resonator 2 is connected to the first conductor 4 through the input tap 41, and the second-order resonator 3 is connected to the second conductor through the output tap 51.

[0083] Among them, Figure 8 As shown, the first conductor 4 and the second conductor can be metal plates or metal sheets with excellent conductive properties such as copper plates, the first tap and the second tap can also be structures such as metal sheets, or transmission lines such as conductive wires, and the first tap and the second tap can be buried in the dielectric matrix 1. The first conductor 4 and the second conductor can be attached to the outside of the dielectric matrix 1, or partially buried in the dielectric matrix 1 and partially exposed. The first-order resonator 2 buried in the dielectric matrix 1 can be connected to the first conductor 4 through the first tap, and the second-order resonator 3 buried in the dielectric matrix 1 can be connected to the second conductor through the second tap. By attaching each conductor to the surface of the dielectric matrix 1 and burying each tap in the dielectric matrix 1, the volume of the filter can be effectively reduced, and the adverse effects of environmental factors on the taps, resonators, etc. can be prevented.

[0084] As a specific implementation method, Figure 1 and Fig. 9 As shown, the multi-zero-point bandpass filter also includes a first floor 6 and a second floor 7, which can be metal plates. The first floor 6 and the second floor 7 are respectively attached to the dielectric substrate 1 on two sides adjacent to and opposite to the first conductor 4 and the second conductor. The first floor 6 and the second floor 7 can have the same structure. Among them, the first compensation pole 221, the second compensation pole 222, the third compensation pole 223, the fourth compensation pole 231, the fifth compensation pole 232 and the sixth compensation pole 233 of the first-order resonator 2 are all connected to the first floor 6, and the first compensation pole 221, the second compensation pole 222, the third compensation pole 223, the fourth compensation pole 231, the fifth compensation pole 232 and the sixth compensation pole 233 of the second-order resonator 3 are all connected to the second floor 7 to achieve grounding.

[0085] It should be noted that, in this embodiment, Figure 1 As shown, the dielectric substrate 1 is a rectangular parallelepiped, and its length direction is defined as the X direction, the width direction is the Y direction, and the height direction is the Z direction. The first conductor 4 and the second conductor are respectively located on both sides of the dielectric substrate 1 in the X direction, and the first floor 6 and the second floor 7 are respectively located on both sides of the dielectric substrate 1 in the Y direction. Fig. 9 As shown, the first floor 6 and the second floor 7 have a larger area. In this embodiment, Figure 1 As shown, the first floor 6 and the second floor 7 can cover both sides of the dielectric substrate 1, thereby providing more selectivity for the grounding positions of the first-order resonator 2 and the second-order resonator 3, making the grounding more flexible.

[0086] As a specific implementation method, Figure 1 and Fig.10 As shown, the multi-zero-point bandpass filter further includes a first shielding plate 8 and a second shielding plate 9, which can be metal plates. The first shielding plate 8 and the second shielding plate 9 are respectively attached to the dielectric substrate 1 on two sides adjacent to and opposite to the first conductor 4, the second conductor, the first floor 6 and the second floor 7. In this embodiment, Figure 1 As shown, the first shielding plate 8 and the second shielding plate 9 can be respectively located on both sides of the dielectric substrate 1 in the Z direction, and the first shielding plate 8 and the second shielding plate 9 can shield external electromagnetic interference. At the same time, the first shielding plate 8, the second shielding plate 9, the first floor 6 and the second floor 7 can be enclosed to form a metal cavity, which can provide a flexible grounding method for the internal resonator and reduce the impact of the external electromagnetic environment on the filter performance in engineering applications.

[0087] Specifically, Figure 1 and Fig.10 As shown, the edges of the first shielding plate 8 and the second shielding plate 9 adjacent to the input end and the output end are provided with notches 81. The notches 81 can be used to adjust the capacitance of the input end and the output end to the ground, so as to achieve the purpose of impedance optimization.

[0088] It can be understood that the first shielding plate 8 and the second shielding plate 9 are respectively attached to the dielectric substrate 1. Specifically, the first shielding plate 8 and the second shielding plate 9 can be printed on the dielectric substrate 1 to ensure the reliability of the shielding plates connected to the dielectric substrate 1.

[0089] In addition, it should be noted that the first shielding plate 8 and the second shielding plate 9 are connected to the edges of the first floor 6 and the second floor 7, respectively, so that a metal cavity can be formed between the first shielding plate 8, the second shielding plate 9, the first floor 6 and the second floor 7. In one case, when the first shielding plate 8, the second shielding plate 9, the first floor 6 and the second floor 7 are all metal plates, cracks are easily generated at the joint position of two adjacent metal plates. To this end, in this embodiment, by providing an empty groove 82 on the edges of the first shielding plate 8 and the second shielding plate 9 adjacent to the first floor 6 and the second floor 7, the stress at the connection between the first shielding plate 8 and the second shielding plate 9 and the first floor 6 and the second floor 7 can be relieved, and cracks at the connection position can be effectively prevented. At the same time, cracks caused by printing a large area of ​​metal electrodes can also be prevented, thereby ensuring the reliability of the connection between the first shielding plate 8, the second shielding plate 9, the first floor 6 and the second floor 7.

[0090] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A multi-zero bandpass filter, characterized in that: include: A dielectric substrate and at least two resonators connected to the dielectric substrate, wherein the dielectric substrate comprises an input end, an output end and a ground end, the input sides of some of the at least two resonators are connected to the input end, the output sides of another part of the resonators are connected to the output end, and the ground sides of the at least two resonators are both connected to the ground end; The at least two resonators are stacked and arranged at intervals, and the odd mode and even mode generated by one resonator are coupled with the odd mode and even mode generated by another adjacent resonator, respectively, to generate four signal transmission paths and three transmission zero points; The number of the resonators is two, namely a first-order resonator and a second-order resonator, the input side of the first-order resonator is connected to the input end, the output side of the second-order resonator is connected to the output end, and the ground sides of the first-order resonator and the second-order resonator are both connected to the ground end; The first-order resonator and the second-order resonator have the same structure, and both the first-order resonator and the second-order resonator include a main resonant pole, an upper compensation pole and a lower compensation pole, the upper compensation pole and the lower compensation pole are respectively located on both sides of the main resonant pole, and the upper compensation pole, the main resonant pole and the lower compensation pole are stacked and arranged at intervals; The main resonance pole of the first-order resonator is connected to the input end; The main resonance pole of the second-order resonator is connected to the output end.

2. The multi-zero bandpass filter according to claim 1, characterized in that: The first-order resonator and the second-order resonator are buried in the dielectric matrix.

3. The multi-zero bandpass filter according to claim 1, characterized in that: The projections of the first-order resonator and the second-order resonator partially overlap.

4. The multi-zero bandpass filter according to claim 1, characterized in that: The main resonance pole includes a first branch, a second branch and a third branch. The second branch is located between the first branch and the third branch, and the length of the second branch is longer than that of the first branch and the second branch.

5. The multi-zero bandpass filter according to claim 4, characterized in that: The upper compensation pole includes a first compensation pole, a second compensation pole and a third compensation pole, and the lower compensation pole includes a fourth compensation pole, a fifth compensation pole and a sixth compensation pole; The first compensation pole and the fourth compensation pole are respectively located on both sides of the first branch node, and the first compensation pole, the first branch node and the fourth compensation pole are stacked and arranged at intervals; The second compensation pole and the fifth compensation pole are respectively located on both sides of the second branch node, and the second compensation pole, the second branch node and the fifth compensation pole are stacked and arranged at intervals; The third compensation pole and the sixth compensation pole are respectively located on both sides of the third branch node, and the third compensation pole, the third branch node and the sixth compensation pole are stacked and arranged at intervals; The first compensation pole, the second compensation pole, the third compensation pole, the fourth compensation pole, the fifth compensation pole and the sixth compensation pole each include a first end and a second end, the first ends of the first compensation pole, the second compensation pole, the third compensation pole, the fourth compensation pole, the fifth compensation pole and the sixth compensation pole are each connected to the ground end, and the second ends of the first compensation pole, the second compensation pole, the third compensation pole, the fourth compensation pole, the fifth compensation pole and the sixth compensation pole are each suspended.

6. The multi-zero bandpass filter according to claim 1, characterized in that: The multi-zero-point bandpass filter also includes a first conductor, a second conductor, an input tap and an output tap. The first conductor and the second conductor are respectively attached to both sides of the dielectric substrate. The first conductor forms the input end, and the second conductor forms the output end. The first-order resonator is connected to the first conductor through the input tap, and the second-order resonator is connected to the second conductor through the output tap.

7. The multi-zero bandpass filter according to claim 6, characterized in that: The multi-zero-point bandpass filter further comprises a first floor and a second floor, wherein the first floor and the second floor are respectively attached to two sides of the dielectric substrate adjacent to and opposite to the first conductor and the second conductor; The first compensation pole, the second compensation pole, the third compensation pole, the fourth compensation pole, the fifth compensation pole and the sixth compensation pole of the first-order resonator are all connected to the first ground plane; The first compensation pole, the second compensation pole, the third compensation pole, the fourth compensation pole, the fifth compensation pole and the sixth compensation pole of the second-order resonator are all connected to the second ground plane.

8. The multi-zero bandpass filter according to claim 7, characterized in that: The multi-zero-point bandpass filter also includes a first shielding plate and a second shielding plate, which are respectively attached to two sides of the dielectric substrate that are adjacent to and opposite to the first conductor, the second conductor, the first floor and the second floor.

9. The multi-zero bandpass filter according to claim 8, characterized in that: Notches are provided on the edges of the first shielding plate and the second shielding plate adjacent to the input end and the output end.

10. The multi-zero bandpass filter according to claim 8, characterized in that: Empty grooves are provided on the edges of the first shielding plate and the second shielding plate adjacent to the first floor panel and the second floor panel.

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