A patch cavity filter

Abstract

The embodiment of the present application provides a patch cavity filter, and relates to the technical field of filters.The patch cavity filter comprises: a plurality of dielectric substrates which are sequentially and laminatedly arranged; a first patch, which is arranged between two adjacent dielectric substrates; a metal ground plate, which is arranged between another two adjacent dielectric substrates; and a second patch, which is arranged between still another two adjacent dielectric substrates; so that the first patch, the metal ground plate and the second patch are sequentially and spacedly arranged along the laminating direction of the dielectric substrates; an input part, which is coupled with the first patch; and an output part, which is coupled with the second patch.The patch cavity filter provided by the embodiment of the present application solves the problem that it is difficult to improve the stopband bandwidth while reducing the size of the filter in the prior art.

Description

Technical Field

[0001] This application relates to the technical field of filters, and more particularly to a patch cavity filter. Background Technology

[0002] With the development of communication systems, filters play an irreplaceable role in suppressing noise and clutter.

[0003] In related technologies, there are various design methods for filters, and therefore, different design methods are often used to meet different performance requirements. For example, the stopband bandwidth can be improved by using low-pass filter cascading, but the circuit size will increase; if three-dimensional packaging technology is used to improve the circuit size, the design cost will increase significantly.

[0004] However, when improving filter performance using the methods described above, it is difficult to reduce the filter size while simultaneously improving the stopband bandwidth. Summary of the Invention

[0005] This application provides a patch cavity filter to solve the problem in the prior art that it is difficult to reduce the size of the filter while improving the stopband bandwidth.

[0006] This application provides a patch cavity filter, including:

[0007] Multiple dielectric substrates stacked sequentially;

[0008] A first patch is disposed between two adjacent dielectric substrates;

[0009] A metal ground plane, wherein the metal ground plane is disposed between two other adjacent dielectric substrates;

[0010] The second patch is disposed between two adjacent dielectric substrates;

[0011] So that the first patch, the metal ground plane and the second patch are arranged at intervals along the stacking direction of the dielectric substrate;

[0012] An input element, which is coupled to the first patch;

[0013] An output component, which is coupled to the second patch.

[0014] In one possible implementation, the plurality of dielectric substrates include a first dielectric substrate, a second dielectric substrate, a third dielectric substrate, and a fourth dielectric substrate;

[0015] The input device is disposed on the first dielectric substrate;

[0016] The first patch is disposed between the first dielectric substrate and the second dielectric substrate;

[0017] The metal ground plane is disposed between the second dielectric substrate and the third dielectric substrate;

[0018] The second patch is disposed between the third dielectric substrate and the fourth dielectric substrate;

[0019] The output component is disposed on the fourth dielectric substrate.

[0020] In one possible implementation, the input device includes an input microstrip line disposed on a corresponding surface of the dielectric substrate opposite to the first patch, the input microstrip line being coupled to the first patch.

[0021] In one possible implementation, the input device further includes a low-impedance input feed line and a high-impedance input short line, wherein the input microstrip line, the low-impedance input feed line, and the high-impedance input short line are located on the same surface of the corresponding dielectric substrate.

[0022] The input microstrip line, the low-impedance input feed line, and the high-impedance input short line are connected in sequence, and the high-impedance input short line is coupled to the first patch.

[0023] In one possible implementation, the input device further includes an input feed post that penetrates the corresponding dielectric substrate, and the high-impedance input short line is coupled to the first patch through the input feed post.

[0024] In one possible implementation, both the first patch and the second patch are configured as semi-circular structures, and the projections of the first patch on the metal ground plane and the projections of the second patch on the metal ground plane are centrally symmetrical about the center of the metal ground plane.

[0025] In one possible implementation, the straight edge of the first patch is parallel to any long edge of the metal ground plane, the extension direction of the low-impedance input feed line is perpendicular to the straight edge of the first patch, and the high-impedance input short line extends radially along the first patch.

[0026] In one possible implementation, the metal ground plane has a coupling groove, the center of which coincides with the center of the metal ground plane.

[0027] In one possible implementation, through holes are formed on the dielectric substrate corresponding to the first patch, the metal ground plane, and the second patch, and the through holes simultaneously penetrate the first patch, the metal ground plane, and the second patch.

[0028] In one possible implementation, each of the through holes is interconnected, and the interconnected through holes form a through hole group. Two through hole groups are provided, and the two through hole groups are symmetrically distributed on opposite sides of the coupling groove.

[0029] This application provides a patch cavity filter, which comprises: multiple dielectric substrates stacked sequentially; a first patch disposed between two adjacent dielectric substrates; a metal ground plane disposed between two other adjacent dielectric substrates; a second patch disposed between yet another pair of adjacent dielectric substrates; such that the first patch, metal ground plane, and second patch are arranged at intervals along the stacking direction of the dielectric substrates; an input element coupled to the first patch; and an output element coupled to the second patch. Thus, by placing patch resonators (i.e., the first patch and the second patch) and a metal ground plane between different dielectric substrates, selective filtering of specific frequencies can be achieved, optimizing the wide stopband performance of the filter. Furthermore, the resulting multilayer structure allows for a more compact filter size while optimizing performance. This achieves high filter selectivity, a wide stopband suppression frequency band, and a compact planar size, thereby controlling the filter size while maintaining a wide stopband, solving the problem in the prior art of difficulty in reducing filter size while improving stopband bandwidth. Attached Figure Description

[0030] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0031] Figure 1 This is a schematic diagram of the structure of the patch cavity filter provided in the embodiments of this application;

[0032] Figure 2 A schematic diagram of the passband transmission curve of the patch cavity filter provided in the embodiments of this application;

[0033] Figure 3 This is a schematic diagram illustrating the out-of-band suppression of the patch cavity filter provided in an embodiment of this application.

[0034] Explanation of reference numerals in the attached figures:

[0035] 100 - Dielectric substrate; 110 - First dielectric substrate; 120 - Second dielectric substrate; 130 - Third dielectric substrate; 140 - Fourth dielectric substrate;

[0036] 200 - First patch;

[0037] 300 - Metal Grounding Plate;

[0038] 400 - Second patch;

[0039] 500 - Input component; 510 - Input microstrip line; 520 - Low impedance input feed line; 530 - High impedance input short line; 540 - Input feed post;

[0040] 600 - Output component; 610 - Output microstrip line; 620 - Low impedance output feed line; 630 - High impedance output short line; 640 - Output feed post;

[0041] 700-Coupled Groove;

[0042] 800 - Through hole group; 810 - Through hole.

[0043] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0044] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0045] In related technologies, there are various design methods for filters. Therefore, different design methods are often used to meet different performance requirements. Currently, the existing wide stopband design methods usually include the following: (1) cascaded low-pass filter method; (2) introducing transmission zeros, such as loading stub resonators or using defective ground structures.

[0046] However, while the transmission zero method is effective, it presents a trade-off between design complexity and performance, resulting in lower cost-effectiveness for wide-stopband designs. Cascading low-pass filters can improve stopband bandwidth, but this increases circuit size. While 3D packaging technology can further reduce circuit size, it significantly increases design costs. Consequently, when designing or improving filter performance using existing methods, it is difficult to simultaneously improve stopband bandwidth and reduce filter size.

[0047] Therefore, this application provides a patch cavity filter, including: a plurality of dielectric substrates stacked sequentially; a first patch disposed between two adjacent dielectric substrates; a metal ground plane disposed between two more adjacent dielectric substrates; a second patch disposed between yet another pair of adjacent dielectric substrates; such that the first patch, the metal ground plane, and the second patch are sequentially spaced along the stacking direction of the dielectric substrates; an input element coupled to the first patch; and an output element coupled to the second patch. Thus, by placing patch resonators (i.e., the first patch and the second patch) and a metal ground plane between different dielectric substrates, selective filtering of specific frequencies can be achieved, optimizing the wide stopband performance of the filter; and the resulting multilayer structure allows for a more compact filter size while optimizing performance; achieving high filter selectivity, a wide stopband suppression frequency band, and a compact planar size, thereby enabling control of the filter size while maintaining a wide stopband, solving the problem in the prior art of difficulty in reducing filter size while improving stopband bandwidth.

[0048] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0049] like Figure 1 As shown in the embodiment of this application, a patch cavity filter includes:

[0050] Multiple dielectric substrates 100 are stacked sequentially.

[0051] The first patch 200 is disposed between two adjacent dielectric substrates 100;

[0052] A metal ground plane 300 is disposed between two adjacent dielectric substrates 100.

[0053] The second patch 400 is disposed between two adjacent dielectric substrates 100;

[0054] So that the first patch 200, the metal ground plane 300 and the second patch 400 are arranged at intervals along the stacking direction of the dielectric substrate 100;

[0055] Input component 500, which is coupled to the first patch 200;

[0056] Output component 600 is coupled to the second patch 400.

[0057] The number of dielectric substrates 100 can be reasonably set according to actual needs. In this embodiment, for example... Figure 1 As shown, four dielectric substrates 100 are provided, and the plurality of dielectric substrates 100 include a first dielectric substrate 110, a second dielectric substrate 120, a third dielectric substrate 130 and a fourth dielectric substrate 140, and each dielectric substrate 100 is stacked vertically. The first patch 200 and the second patch 400 are both patch resonators.

[0058] At this time, the input element 500 is disposed on the first dielectric substrate 110;

[0059] The first patch 200 is disposed between the first dielectric substrate 110 and the second dielectric substrate 120;

[0060] A metal ground plane 300 is disposed between the second dielectric substrate 120 and the third dielectric substrate 130;

[0061] The second patch 400 is disposed between the third dielectric substrate 130 and the fourth dielectric substrate 140;

[0062] The output component 600 is disposed on the fourth dielectric substrate 140.

[0063] Therefore, by placing patch resonators (i.e., the first patch 200 and the second patch 400) and a metal ground plane 300 between different dielectric substrates 100, selective filtering of specific frequencies can be achieved, optimizing the wide stopband performance of the filter. Furthermore, the resulting multi-layer structure can make the filter size more compact while optimizing performance. It achieves the characteristics of high filter selectivity, wide stopband suppression, and compact planar size, thus enabling control of the filter size while having a wide stopband. Moreover, it can be used for multi-band filter implementation and has good out-of-band suppression characteristics, solving the problem in the prior art of reducing the filter size while improving the stopband bandwidth.

[0064] Furthermore, such as Figure 1 As shown, each dielectric substrate 100 is configured as a rectangular structure, and the first patch 200 and the second patch 400 are configured as semi-circular structures. The projections of the first patch 200 on the metal ground plane 300 and the second patch 400 on the metal ground plane 300 are centrally symmetrical about the center of the metal ground plane 300.

[0065] This allows for symmetrical input and output structures in the filter, improving its performance.

[0066] In some embodiments, such as Figure 1As shown, the input device 500 includes an input microstrip line 510, which is disposed on the surface of the corresponding dielectric substrate 100 away from the first patch 200, and the input microstrip line 510 is coupled to the first patch 200.

[0067] In this embodiment, the input microstrip line 510 is disposed on the surface of the first dielectric substrate 110 opposite to the first patch 200, i.e., on the upper surface of the first dielectric substrate 110, so that the input microstrip line 510 serves as a signal input terminal, and signals can be input through the input microstrip line 510. For example, in practice, the input microstrip line 510 can be a 50-ohm microstrip line.

[0068] The input device 500 also includes a low-impedance input feed line 520 and a high-impedance input short line 530, with the input microstrip line 510, the low-impedance input feed line 520 and the high-impedance input short line 530 located on the same surface of the corresponding dielectric substrate 100.

[0069] The input microstrip line 510, the low-impedance input feed line 520, and the high-impedance input short line 530 are connected in sequence, and the high-impedance input short line 530 is coupled to the first patch 200.

[0070] The input device 500 also includes an input feed post 540, which penetrates the corresponding dielectric substrate 100. The high-impedance input short line 530 is coupled to the first patch 200 through the input feed post 540.

[0071] Specifically, the impedance of the high-impedance input short line 530 is higher than that of the low-impedance input feed line 520. The input microstrip line 510, the low-impedance input feed line 520, and the high-impedance input short line 530 are all located on the upper surface of the first dielectric substrate 110. These three lines are connected sequentially. The input feed post 540 is a metal post that vertically penetrates the first dielectric substrate 110. The upper end of the input feed post 540 is connected to the high-impedance input short line 530, and the lower end is connected to the first patch 200, thereby coupling the high-impedance input short line 530 to the first patch 200 through the input feed post 540.

[0072] Therefore, at the signal input end, the traditional uniform impedance feed line is replaced with a non-uniform impedance feed line (i.e., a low-impedance input feed line 520 and a high-impedance input short line 530) to reduce the contact area between the feed line and the patch resonator, thereby exciting the higher harmonics of the patch resonator and facilitating wideband stopband suppression. Furthermore, signal transmission is achieved through the input feed post 540, and the feed position is selected based on the electric field distribution to excite the TM of the patch resonator. 11The mode forms a passband and simultaneously suppresses multiple high-order noises with weak electric field amplitude at the feed position of the patch resonator. Therefore, the combination of the input feed post 540, the first patch 200, and the high-impedance input short line 530 can achieve harmonic suppression and improve the performance of the filter's wideband stopband suppression.

[0073] Correspondingly, such as Figure 1 As shown, the output device 600 includes an output microstrip line 610, a low-impedance output feed line 620, a high-impedance output short line 630, and an output feed post 640. The output microstrip line 610 can also be a 50-ohm microstrip line, and the impedance of the high-impedance output short line 630 is higher than that of the low-impedance output feed line 620.

[0074] Specifically, the output microstrip line 610, the low-impedance output feed line 620, and the high-impedance output short line 630 are all disposed on the surface of the fourth dielectric substrate 140 opposite to the second patch 400 (i.e., the lower surface of the fourth dielectric substrate 140), and the output microstrip line 610, the low-impedance output feed line 620, and the high-impedance output short line 630 are connected sequentially. The output feed post 640 is a metal post that vertically penetrates the fourth dielectric substrate 140. The upper end of the output feed post 640 is connected to the second patch 400, and the lower end is connected to the high-impedance output short line 630. This makes the output component 600 and the input component 500 centrally symmetrical about the metal ground plane 300, thereby improving the symmetry of the input and output structures and optimizing the performance.

[0075] In practice, the end of the input microstrip line 510 away from the low-impedance input feed line 520 can be extended to the upper surface edge of the first dielectric substrate 110; and the end of the output microstrip line 610 away from the low-impedance output feed line 620 can be extended to the lower surface edge of the fourth dielectric substrate 140.

[0076] Furthermore, such as Figure 1 As shown, the straight edge of the first patch 200 is parallel to any long edge of the metal ground plane 300, the extension direction of the low impedance input feed line 520 is perpendicular to the straight edge of the first patch 200, and the high impedance input short line 530 extends radially along the first patch 200.

[0077] This facilitates the realization of a regular dielectric substrate 100, making full use of the area of ​​the dielectric substrate 100. The high-impedance input short line 530 extends radially along the first patch 200 to obtain the shortest electrical length. At the same time, it is set as a high-impedance input short line 530 with a small linewidth to reduce the vertical coupling between the feed line (i.e., the low-impedance input feed line 520) and the patch resonator, thereby avoiding the generation of some high-order noise.

[0078] In some embodiments, such as Figure 1As shown, a coupling groove 700 is provided on the metal ground plate 300, and the center of the coupling groove 700 coincides with the center of the metal ground plate 300.

[0079] In this embodiment, the coupling groove 700 can be a rectangular structure, or it can be other shapes. The coupling groove 700 is formed in the middle of the metal ground plane 300, and the coupling groove 700 extends along the width direction of the metal ground plane 300, such that the center of the coupling groove 700 coincides with the center of the metal ground plane 300.

[0080] The coupling slot 700 facilitates the coupling of two patch resonators (i.e., the first patch 200 and the second patch 400), generating two transmission poles in the passband. Furthermore, it should be noted that the length and width of the coupling slot 700 affect the frequency distance between the transmission poles, i.e., the coupling strength, with the length having a more sensitive impact on the coupling strength. In addition, the odd-mode electric field transmission characteristics of the coupling slot 700 prevent the transmission of some even-mode resonant modes of the patch resonators, further suppressing some noise.

[0081] In some embodiments, such as Figure 1 As shown, through holes 810 are provided on the dielectric substrate 100 corresponding to the first patch 200, the metal ground plane 300 and the second patch 400, and the through holes 810 pass through the first patch 200, the metal ground plane 300 and the second patch 400.

[0082] Each through hole 810 is interconnected, and the interconnected through holes 810 form a through hole group 800. Two through hole groups 800 are provided, and the two through hole groups 800 are symmetrically distributed on opposite sides of the coupling groove 700.

[0083] In this embodiment, the through-hole 810 is a metallized through-hole 810. Three through-holes 810 form a group, and the three through-holes 810 in the same group are connected sequentially along the width direction to form a through-hole group 800. Two through-hole groups 800 are symmetrically distributed on opposite sides of the coupling groove 700 in the length direction. In other embodiments, other numbers of through-holes 810 can also be set as through-hole groups 800.

[0084] Thus, the via 810 generates a perturbation, increasing the in-band transmission poles and simultaneously creating source-load coupling, generating a transmission zero at the left passband edge. Furthermore, the via group 800 is simultaneously connected to the metal ground plane 300, weakening the electric field near the symmetry plane of the patch resonator (i.e., the first patch 200 and the second patch 400), further improving the high-order clutter suppression capability.

[0085] When implementing the embodiments of this application, as follows: Figure 2As shown, for example, there are three transmission poles in the passband of the filter. Pole 1 is an additional resonant mode generated by the perturbation of the TM11 resonator mode after the via group 800 is added. Pole 2 and pole 3 are generated by two patch resonators (i.e., the first patch 200 and the second patch 400) coupled through the coupling slot 700.

[0086] like Figure 3 As shown, there is a transmission zero on the left side of the filter passband, caused by inductive coupling from the source load after the via group 800 is added. The out-of-band clutter suppression reaches 19.5f0 with a 20dB reduction. The reasons include: (a) The positions of the input feed post 540 and the output feed post 640 are selected at the weakest electric field points of multiple higher-order modes, making it impossible for the corresponding higher-order modes to excite, such as TM. 31 TM 51 TM 32 (b) The coupling strength between the high-impedance input short line 530 and the high-impedance output short line 630 and the corresponding patch is weakened to prevent the excitation of strong edge-field modes, such as TM. 12 TM 13 (c) Coupled slot 700 filters even-mode resonant frequency, such as TM 21 TM 41 (d) The grounding effect of the through-hole group 800 weakens the coupling of higher-order resonant modes that tend to the edge of the patch, thereby achieving an ultra-wide stopband bandwidth.

[0087] In summary, the patch cavity filter provided in this application, by setting patch resonators (i.e., the first patch 200 and the second patch 400) and a metal ground plane 300 between different dielectric substrates 100, can achieve selective filtering of specific frequencies and optimize the wide stopband performance of the filter. Furthermore, the multi-layer structure formed can make the filter size more compact while optimizing performance. It achieves the characteristics of high filtering selectivity, wide stopband suppression frequency band, and compact planar size, thereby enabling the control of the filter size while having a wide stopband. Moreover, it can be used for multi-band filter implementation and has good out-of-band suppression characteristics, solving the problem in the prior art that it is difficult to reduce the size of the filter while improving the stopband bandwidth.

[0088] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A patch cavity filter, characterized by, The application relates to a patch antenna, which comprises: a plurality of dielectric substrates (100) arranged in sequence; a first patch (200) arranged between two adjacent dielectric substrates (100); a metal ground plate (300) arranged between another two adjacent dielectric substrates (100); a second patch (400) arranged between still another two adjacent dielectric substrates (100); the first patch (200), the metal ground plate (300) and the second patch (400) are arranged in sequence along the stacking direction of the dielectric substrates (100); an input element (500) coupled with the first patch (200); an output element (600) coupled with the second patch (400); the input element (500) comprises an input microstrip line (510) arranged on the surface of the corresponding dielectric substrate (100) away from the first patch (200), and the input microstrip line (510) is coupled with the first patch (200); the input element (500) further comprises a low-impedance input feed line (520) and a high-impedance input short line (530), and the input microstrip line (510), the low-impedance input feed line (520) and the high-impedance input short line (530) are located on the same surface of the corresponding dielectric substrate (100); the input microstrip line (510), the low-impedance input feed line (520) and the high-impedance input short line (530) are connected in sequence, and the high-impedance input short line (530) is coupled with the first patch (200); the input element (500) further comprises an input feed column (540) penetrating through the corresponding dielectric substrate (100), and the high-impedance input short line (530) is coupled with the first patch (200) through the input feed column (540); a coupling groove (700) is arranged on the metal ground plate (300), and the center of the coupling groove (700) coincides with the center of the metal ground plate (300); a through hole (810) is arranged on the corresponding dielectric substrate (100) of the first patch (200), the metal ground plate (300) and the second patch (400), and the through hole (810) penetrates through the first patch (200), the metal ground plate (300) and the second patch (400) at the same time; the through holes (810) are communicated with each other, the communicated through holes (810) form a through hole group (800), and the through hole group (800) is arranged in two groups, and the two groups of through hole groups (800) are symmetrically distributed on the opposite sides of the coupling groove (700).

2. The patch cavity filter of claim 1, wherein, The plurality of dielectric substrates (100) comprises a first dielectric substrate (110), a second dielectric substrate (120), a third dielectric substrate (130) and a fourth dielectric substrate (140). The input part (500) is arranged on the first dielectric substrate (110); The first patch (200) is arranged between the first dielectric substrate (110) and the second dielectric substrate (120); The metal ground plate (300) is arranged between the second dielectric substrate (120) and the third dielectric substrate (130); The second patch (400) is arranged between the third dielectric substrate (130) and the fourth dielectric substrate (140); The output part (600) is arranged on the fourth dielectric substrate (140).

3. The patch cavity filter of claim 1, wherein, The first patch (200) and the second patch (400) are both arranged as a semicircular structure, and the projection of the first patch (200) on the metal ground plate (300) and the projection of the second patch (400) on the metal ground plate (300) are centrally symmetrically distributed about the center of the metal ground plate (300).

4. The patch cavity filter of claim 3, wherein, The straight edge of the first patch (200) is parallel to any long edge of the metal ground plate (300), the extension direction of the low-impedance input feed line (520) is perpendicular to the straight edge of the first patch (200), and the high-impedance input stub (530) extends along the radial direction of the first patch (200).

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