Paster cavity filter

Abstract

The embodiment of the invention provides a patch cavity filter, and relates to the technical field of filters, and the patch cavity filter comprises a plurality of dielectric substrates which are sequentially stacked; a first patch, wherein the first patch is arranged between two adjacent dielectric substrates; the metal grounding plate is arranged between the other two adjacent dielectric substrates; the second patch is arranged between another two adjacent dielectric substrates; the first patch, the metal grounding plate and the second patch are sequentially arranged at intervals in the stacking direction of the dielectric substrate; the input part is coupled with the first patch; and the output piece is coupled with the second patch. According to the patch cavity filter provided by the embodiment of the invention, the problem that the size of the filter is difficult to reduce while the stop-band bandwidth is improved in the prior art is solved.

Description

Technical Field

[0001] The present application relates to the technical field of filters, and in particular to a patch cavity filter. Background Art

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

[0003] In the related art, there are various filter design methods, so different design methods are often used to meet different performance requirements. For example, the stopband bandwidth is improved by using the low-pass filter cascade method, but the circuit size will increase; if the circuit size is improved by using three-dimensional packaging technology at this time, the design cost will increase greatly.

[0004] However, when improving the performance of the filter by the above method, it is difficult to reduce the size of the filter while improving the stopband bandwidth. Summary of the invention

[0005] The embodiment of the present 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] The present application provides a patch cavity filter, including:

[0007] A plurality of dielectric substrates stacked in sequence;

[0008] A first patch, the first patch is arranged between two adjacent dielectric substrates;

[0009] A metal grounding plate, the metal grounding plate being arranged between another two adjacent dielectric substrates;

[0010] A second patch, the second patch being arranged between two adjacent dielectric substrates;

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

[0012] an input element coupled to the first patch;

[0013] An output element is coupled to the second patch.

[0014] In a possible implementation manner, 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 member is disposed on the first dielectric substrate;

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

[0017] The metal ground plate is arranged between the second dielectric substrate and the third dielectric substrate;

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

[0019] The output member is arranged on the fourth dielectric substrate.

[0020] In a possible implementation manner, the input element includes an input microstrip line, the input microstrip line is arranged on a surface of the corresponding dielectric substrate away from the first patch, and the input microstrip line is coupled to the first patch.

[0021] In a possible implementation manner, the input component further includes a low-impedance input feed line and a high-impedance input short line, and 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 a possible implementation manner, the input component further includes an input feeding column, the input feeding column penetrates the corresponding dielectric substrate, and the high-impedance input short line is coupled to the first patch through the input feeding column.

[0024] In a possible implementation, the first patch and the second patch are both configured as semicircular structures, and a projection of the first patch on the metal ground plane and a projection of the second patch on the metal ground plane are centrally symmetrically distributed about the center of the metal ground plane.

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

[0026] In a possible implementation manner, a coupling groove is formed on the metal grounding plate, and a center of the coupling groove coincides with a center of the metal grounding plate.

[0027] In a possible implementation manner, through holes are provided on the dielectric substrate corresponding to the first patch, the metal ground plate, and the second patch, and the through holes penetrate the first patch, the metal ground plate, and the second patch at the same time.

[0028] In a possible implementation manner, the through holes are 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 two opposite sides of the coupling slot.

[0029] The embodiment of the present application provides a patch cavity filter, which is provided by: a plurality of dielectric substrates stacked in sequence; a first patch, the first patch is arranged between two adjacent dielectric substrates; a metal ground plate, the metal ground plate is arranged between another two adjacent dielectric substrates; a second patch, the second patch is arranged between another two adjacent dielectric substrates; so that the first patch, the metal ground plate and the second patch are arranged in sequence along the stacking direction of the dielectric substrate; an input component, the input component is coupled with the first patch; an output component, the output component is coupled with the second patch. Thus, by arranging patch resonators (i.e., the first patch and the second patch) and the metal ground plate between different dielectric substrates, selective filtering of specific frequencies can be achieved, and the wide stopband performance of the filter can be optimized; and the formed multilayer structure can make the size of the filter more compact while optimizing the performance; the characteristics of high filtering selectivity, wide stopband suppression frequency band and compact plane size are achieved, so that the size of the filter can be controlled while having a wide stopband, solving the problem in the prior art that it is difficult to reduce the size of the filter while improving the stopband bandwidth. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] 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.

[0031] Figure 1 A schematic diagram of the structure of a patch cavity filter provided in an embodiment of the present application;

[0032] Figure 2 A schematic diagram of a passband transmission curve of a patch cavity filter provided in an embodiment of the present application;

[0033] Figure 3 A schematic diagram of the out-of-band suppression of the patch cavity filter provided in an embodiment of the present application.

[0034] Description of reference numerals:

[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 ground 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 column;

[0040] 600-output component; 610-output microstrip line; 620-low impedance output feed line; 630-high impedance output short line; 640-output feed column;

[0041] 700-coupling slot;

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

[0043] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0044] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0045] In the related art, there are various filter design methods, so different design methods are often used to meet different performance requirements. At present, the existing wide stopband design methods usually include the following: (1) cascade low-pass filter method; (2) introduction of transmission zero point method, such as loading branch resonators or using defective ground structures.

[0046] However, although the introduction of the transmission zero method is effective, there is a contradiction between design complexity and performance, and the cost-effectiveness of wide stopband design is low. The stopband bandwidth is improved by the low-pass filter cascade method, but the circuit size will increase. If the circuit size is improved by three-dimensional packaging technology at this time, the design cost will increase greatly. As a result, when designing or improving the performance of the filter by the existing method, it is difficult to reduce the size of the filter while improving the stopband bandwidth.

[0047] Therefore, the embodiment of the present application provides a patch cavity filter, including: a plurality of dielectric substrates stacked in sequence; a first patch, the first patch is arranged between two adjacent dielectric substrates; a metal ground plate, the metal ground plate is arranged between another two adjacent dielectric substrates; a second patch, the second patch is arranged between another two adjacent dielectric substrates; so that the first patch, the metal ground plate and the second patch are arranged in sequence along the stacking direction of the dielectric substrate; an input component, the input component is coupled with the first patch; an output component, the output component is coupled with the second patch. Therefore, by arranging patch resonators (i.e., the first patch and the second patch) and the metal ground plate between different dielectric substrates, selective filtering of specific frequencies can be achieved, and the wide stopband performance of the filter can be optimized; and the multilayer structure formed can make the size of the filter more compact while optimizing the performance; the characteristics of high filtering selectivity, wide stopband suppression frequency band and compact plane size are achieved, so that the size of the filter can be controlled while having a wide stopband, solving the problem in the prior art that it is difficult to reduce the size of the filter while improving the stopband bandwidth.

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

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

[0050] A plurality of dielectric substrates 100 stacked in sequence;

[0051] A first patch 200, the first patch 200 is arranged between two adjacent dielectric substrates 100;

[0052] A metal grounding plate 300, wherein the metal grounding plate 300 is disposed between another two adjacent dielectric substrates 100;

[0053] A second patch 400, the second patch 400 is disposed between two adjacent dielectric substrates 100;

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

[0055] An input element 500 , the input element 500 is coupled to the first patch 200 ;

[0056] The output element 600 is coupled to the second patch 400 .

[0057] The number of dielectric substrates 100 can be reasonably set according to actual needs. 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 member 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] The metal ground plate 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 member 600 is disposed on the fourth dielectric substrate 140 .

[0063] Therefore, by arranging patch resonators (i.e., the first patch 200 and the second patch 400) and the metal ground plate 300 between different dielectric substrates 100, selective filtering of specific frequencies can be achieved and the wide stopband performance of the filter can be optimized; and the formed multi-layer structure can make the size of the filter more compact while optimizing the performance; the characteristics of high filtering selectivity, wide stopband suppression frequency band, and compact plane size are achieved, so that the size of the filter can be controlled while having a wide stopband, and it can be used for the realization of multi-band filters 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.

[0064] Further, such as Figure 1 As shown, each dielectric substrate 100 is configured as a rectangular structure, the first patch 200 and the second patch 400 are configured 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.

[0065] In this way, the input and output structures in the filter can be symmetrical, thereby improving the use effect of the filter.

[0066] In some embodiments, Figure 1As shown, the input element 500 includes an input microstrip line 510 . The input microstrip line 510 is disposed on a surface of the corresponding dielectric substrate 100 away from the first patch 200 . 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 away from the first patch 200, that is, the upper surface of the first dielectric substrate 110, so that the input microstrip line 510 is used as the input end of the signal, and the signal can be input through the input microstrip line 510. In implementation, illustratively, the input microstrip line 510 can be a 50-ohm microstrip line.

[0068] The input element 500 further includes a low impedance input feed line 520 and a high impedance input short line 530. 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.

[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 element 500 further includes an input feeding column 540 , which penetrates the corresponding dielectric substrate 100 , and the high-impedance input short line 530 is coupled to the first patch 200 via the input feeding column 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. The input microstrip line 510, the low impedance input feed line 520 and the high impedance input short line 530 are connected in sequence. The input feed column 540 is a metal column, and the input feed column 540 vertically penetrates the first dielectric substrate 110. The upper end of the input feed column 540 is connected to the high impedance input short line 530, and the lower end is connected to the first patch 200, so that the high impedance input short line 530 is coupled to the first patch 200 through the input feed column 540.

[0072] Therefore, at the input end of the signal, the traditional uniform impedance feed line is changed to 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, and to excite the high-order harmonics of the patch resonator, thereby facilitating the realization of broadband stopband suppression. In addition, the signal is transmitted through the input feed column 540, and the feeding position is selected according to the electric field distribution to excite the TM of the patch resonator. 11The mode forms a passband and suppresses multiple high-order clutters with weak electric field amplitude of the patch resonator at the feeding position. Therefore, the input feeding column 540 is combined with the first patch 200 and the high-impedance input short line 530 to achieve harmonic suppression and improve the use effect of the filter's broadband stopband suppression.

[0073] Correspondingly, such as Figure 1 As shown, the output element 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 column 640 . The output microstrip line 610 may also be a 50 ohm microstrip line. 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 arranged on the surface of the fourth dielectric substrate 140 away from 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 in sequence. The output feed column 640 is a metal column, and the output feed column 640 vertically penetrates the fourth dielectric substrate 140. The upper end of the output feed column 640 is connected to the second patch 400, and the lower end is connected to the high-impedance output short line 630. The output component 600 and the input component 500 are centrally symmetrical structures with respect to the metal ground plate 300, thereby improving the symmetry of the input and output structures and optimizing the use effect.

[0075] During implementation, the end of the input microstrip line 510 away from the low impedance input feeder 520 can be extended to the upper edge of the first dielectric substrate 110 ; the end of the output microstrip line 610 away from the low impedance output feeder 620 can be extended to the lower edge of the fourth dielectric substrate 140 .

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

[0077] Thus, it is easy to realize the regular dielectric substrate 100 and fully utilize the area of ​​the dielectric substrate 100. The high-impedance input short line 530 extends along the radial direction of the first patch 200 to obtain the shortest electrical length, and is set as a high-impedance input short line 530 with a small line width 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 clutter.

[0078] In some embodiments, Figure 1As shown, a coupling slot 700 is formed on the metal grounding plate 300 , and the center of the coupling slot 700 coincides with the center of the metal grounding plate 300 .

[0079] In this embodiment, the coupling slot 700 may be a rectangular structure, or other shapes. The coupling slot 700 is opened in the middle of the metal ground plate 300, and the coupling slot 700 extends along the width direction of the metal ground plate 300, so that the center of the coupling slot 700 coincides with the center of the metal ground plate 300.

[0080] Under the action of the coupling slot 700, it is easy to achieve the coupling of the two patch resonators (i.e., the first patch 200 and the second patch 400), and generate two transmission poles in the passband. In addition, it should be noted that the length and width of the coupling slot 700 affect the frequency distance of the transmission pole, i.e., the coupling strength, wherein the length is more sensitive to the coupling strength. In addition, the odd-mode electric field transmission characteristics of the coupling slot 700 make it impossible for some even-mode resonant modes of the patch resonator to be transmitted, further suppressing some clutter.

[0081] In some embodiments, Figure 1 As shown, the dielectric substrate 100 corresponding to the first patch 200 , the metal ground plate 300 and the second patch 400 is provided with a through hole 810 , and the through hole 810 penetrates the first patch 200 , the metal ground plate 300 and the second patch 400 at the same time.

[0082] The through holes 810 are 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 two opposite sides of the coupling slot 700 .

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

[0084] Thus, a perturbation is generated through the through hole 810, which increases the transmission pole in the band and forms a source-load coupling, thereby generating a transmission zero at the left passband edge. In addition, the through hole group 800 is connected to the metal ground plate 300 at the same time, so that the electric field near the symmetry plane of the patch resonator (i.e., the first patch 200 and the second patch 400) is weakened, further improving the high-order clutter suppression capability.

[0085] When the embodiment of the present application is implemented, Figure 2As shown, exemplarily, there are three transmission poles in the filter passband, where pole 1 is generated by the addition of the through hole group 800, which causes a perturbation to the TM11 resonator mode and thus generates an additional resonant mode, and poles 2 and 3 are generated by coupling two patch resonators (i.e., the first patch 200 and the second patch 400) through the coupling slot 700.

[0086] like Figure 3 As shown, there is a transmission zero on the left side of the filter passband, which is caused by the source load inductive coupling after the through hole group 800 is added, and the out-of-band clutter suppression reaches 19.5f0 by 20dB. The reasons include: (a) The positions of the input feed column 540 and the output feed column 640 are selected at the weakest points of the electric field of multiple high-order modes, so that the corresponding high-order modes such as TM cannot be excited. 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 avoid the excitation of the mode with strong edge field, such as TM 12 ,TM 13 etc.; (c) The coupling slot 700 filters the even-mode resonant frequency, such as TM 21 ,TM 41 etc.; (d) The grounding effect of the through hole group 800 weakens the coupling of higher-order resonant modes tending to the edge of the patch, thereby achieving an ultra-wide stopband bandwidth.

[0087] In summary, the patch cavity filter provided in the embodiment of the present application can achieve selective filtering of specific frequencies and optimize the wide stopband performance of the filter by arranging patch resonators (i.e., the first patch 200 and the second patch 400) and the metal ground plate 300 between different dielectric substrates 100; and the formed multi-layer structure can make the size of the filter more compact while optimizing the performance; it achieves the characteristics of high filtering selectivity, wide stopband suppression frequency band, and compact planar size, so that the size of the filter can be controlled while having a wide stopband, and 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 those skilled in the art will readily conceive of other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. The present invention is intended to cover any variations, uses or adaptations of the present invention, which follow the general principles of the present invention and include common knowledge or customary technical means in the art not disclosed by the present invention, are not limited to the precise structure described above and shown in the drawings, and may be modified and changed in various ways without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A patch cavity filter, characterized in that: include: A plurality of dielectric substrates (100) stacked in sequence; A first patch (200), the first patch (200) being arranged between two adjacent dielectric substrates (100); A metal grounding plate (300), the metal grounding plate (300) being arranged between another two adjacent dielectric substrates (100); A second patch (400), the second patch (400) being arranged between two adjacent dielectric substrates (100); so that the first patch (200), the metal ground plate (300) and the second patch (400) are sequentially arranged at intervals along the stacking direction of the dielectric substrate (100); An input component (500), the input component (500) being coupled to the first patch (200); An output element (600), the output element (600) being coupled to the second patch (400); The input element (500) comprises an input microstrip line (510), the input microstrip line (510) being arranged on a surface of the corresponding dielectric substrate (100) facing away from the first patch (200), and the input microstrip line (510) being coupled to 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), wherein 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 to the first patch (200); The input component (500) further comprises an input feeding column (540), wherein the input feeding column (540) penetrates the corresponding dielectric substrate (100), and the high-impedance input short line (530) is coupled to the first patch (200) via the input feeding column (540).

2. A patch cavity filter according to claim 1, characterized in that: 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); The input component (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 grounding 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 component (600) is arranged on the fourth dielectric substrate (140).

3. A patch cavity filter according to claim 1, characterized in that: The first patch (200) and the second patch (400) are both arranged as semicircular structures, and the projection of the first patch (200) on the metal grounding plate (300) and the projection of the second patch (400) on the metal grounding plate (300) are centrally symmetrically distributed about the center of the metal grounding plate (300).

4. A patch cavity filter according to claim 3, characterized in that: 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 short line (530) extends in the radial direction of the first patch (200).

5. A patch cavity filter according to any one of claims 1 to 4, characterized in that: A coupling slot (700) is provided on the metal grounding plate (300), and the center of the coupling slot (700) coincides with the center of the metal grounding plate (300).

6. A patch cavity filter according to claim 5, characterized in that: The dielectric substrate (100) corresponding to the first patch (200), the metal ground plate (300) and the second patch (400) is provided with a through hole (810), and the through hole (810) simultaneously penetrates the first patch (200), the metal ground plate (300) and the second patch (400).

7. A patch cavity filter according to claim 6, characterized in that: The through holes (810) are 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 two opposite sides of the coupling slot (700).

Images