An integrated microwave ceramic waveguide dual-band filter

Abstract

The present invention discloses an integrated microwave ceramic waveguide dual-band filter, belonging to the field of microwave communication technology. The filter comprises: a ceramic dielectric body, and a first dielectric waveguide power divider, a second dielectric waveguide power divider, a first dielectric waveguide filter, a second dielectric waveguide filter, and an impedance matching structure integrated on the ceramic dielectric body; the center frequency of the first dielectric waveguide filter is lower than the center frequency of the second dielectric waveguide filter, and an impedance matching structure is provided between the two dielectric waveguide power dividers and the two dielectric waveguide filters with different center frequencies. The impedance matching structure can be equivalent to a series capacitor and inductor structure, so that when the dual-band filter operates in one frequency band, the impedance mismatch caused by the filter in the other frequency band is suppressed, thereby improving the device's return loss in both frequency bands. The present invention realizes an integrated design of the power divider, impedance matching structure, and filter, which can reduce device production costs, device size, and insertion loss.

Description

Technical Field

[0001] The present invention belongs to the field of microwave communication technology, and more specifically, relates to an integrated microwave ceramic waveguide dual-frequency filter. Background Art

[0002] With the rapid development of contemporary communications technology, spectrum resources are becoming increasingly scarce, and their division is becoming increasingly detailed. To fully utilize existing spectrum resources and avoid interference between different communication standards, it is necessary to set up multiple, simultaneously operating communication frequency bands within the communication system. Using high-performance dual-band or multi-band filters is one effective solution.

[0003] The advancement of communication technology has placed higher demands on the loss and size of communication equipment. In multi-frequency applications, using two single filters to operate directly will increase system loss, size, and production costs. Although dual-band filters made from microstrip linear stepped impedance resonators and branch-loaded resonators have a simple structure and a small size, their high insertion loss and low power handling make them difficult to use in communication base stations. Compared to microstrip filters, ceramic dielectric filters offer advantages such as high Q, low loss, and small size.

[0004] In the prior art, a microstrip power splitter is often combined with two dielectric filters with different center frequencies to create a dual-band filter. However, due to the presence of the microstrip power splitter, this dual-band filter often suffers from high device losses. Furthermore, to avoid the impedance mismatch caused by connecting the two filters in parallel, an impedance matching structure consisting of lumped capacitors or inductors is required between the microstrip power splitter and the dielectric filter. This impedance matching network, comprised of lumped components, further increases the size and losses of the dual-band filter. Summary of the Invention

[0005] In response to the defects of the existing technology and the need for improvement, the present invention provides an integrated microwave ceramic waveguide dual-band filter, which aims to reduce the size and manufacturing cost of the dual-band filter through an integrated design, while also effectively improving the insertion loss and return loss characteristics within the two passbands of the dual-band filter.

[0006] To achieve the above objectives, according to one aspect of the present invention, an integrated microwave ceramic waveguide dual-band filter is provided, comprising:

[0007] A ceramic dielectric body and a first dielectric waveguide power divider, a second dielectric waveguide power divider, a first dielectric waveguide filter, a second dielectric waveguide filter and an impedance matching structure integrated on the ceramic dielectric body;

[0008] The first dielectric waveguide power divider includes an input end and two output ends, and the second dielectric waveguide power divider includes two input ends and one output end; the impedance matching structure includes a first inductive coupling structure, a second inductive coupling structure, a first capacitive coupling structure, and a second capacitive coupling structure;

[0009] The first output end of the first dielectric waveguide power divider is coupled to the first dielectric waveguide filter via a first inductive coupling structure, and the second output end is coupled to the second dielectric waveguide filter via a first capacitive coupling structure;

[0010] The first input end of the second dielectric waveguide power divider is coupled to the first dielectric waveguide filter via a second inductive coupling structure, and the second input end is coupled to the second dielectric waveguide filter via a second capacitive coupling structure;

[0011] The center frequency of the first dielectric waveguide filter is lower than the center frequency of the second dielectric waveguide filter; the input end of the first dielectric waveguide power divider and the output end of the second dielectric waveguide power divider are respectively used as the input end and output end of the dual-band filter to connect to an external circuit.

[0012] Furthermore,

[0013] The first inductive coupling structure is a coupling structure formed by a first coupling groove and a first shallow blind hole;

[0014] The second inductive coupling structure is a coupling structure formed by the first coupling groove and the second shallow blind hole;

[0015] The first capacitive coupling structure is a coupling structure formed by the second coupling groove and the first deep blind hole;

[0016] The second capacitive coupling structure is a coupling structure formed by a second coupling groove and a second deep blind hole.

[0017] Furthermore,

[0018] The first inductive coupling structure and the second inductive coupling structure are both equivalent to a capacitor and an inductor in series structure, and the inductive reactance of the inductor is greater than the capacitive reactance of the capacitor;

[0019] The first capacitive coupling structure and the second capacitive coupling structure are both equivalent to a capacitor and an inductor in series structure, and the capacitive reactance of the capacitor is greater than the inductive reactance of the inductor.

[0020] Furthermore, the two dielectric waveguide power dividers are both H-plane T-type dielectric waveguide power dividers.

[0021] Furthermore, a rectangular impedance matching slot is provided on the H-plane T-shaped dielectric waveguide power divider.

[0022] Furthermore, the two dielectric waveguide filters each include a capacitive CQ coupling structure for generating a pair of position-adjustable transmission zeros outside the passband of the filter.

[0023] Furthermore, the surfaces of the two dielectric waveguide filters have tuning holes, coupling slots and capacitive coupling blind holes;

[0024] The tuning hole is a blind hole for adjusting the resonant frequency of the resonant cavity; the coupling slot is a rectangular slot for adjusting the inductive coupling between the resonant cavities; and the capacitive coupling blind hole is used to form a capacitive CQ coupling structure in the filter.

[0025] Furthermore, the two dielectric waveguide filters are both ceramic waveguide filters.

[0026] Furthermore, the outer surface of the ceramic dielectric body is plated with a conductive metal layer.

[0027] Furthermore, the microwave signal of the dual-frequency filter is TE 10 mode for transmission.

[0028] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects:

[0029] (1) The integrated microwave ceramic waveguide dual-band filter of the present invention is provided with an impedance matching structure between two dielectric waveguide power dividers and two dielectric waveguide filters with different center frequencies. The impedance matching structure forms two inductive coupling structures between the dielectric waveguide power divider and the filter with a low center frequency, and two capacitive coupling structures between the dielectric waveguide power divider and the filter with a high center frequency. Impedance matching can be achieved within the two passband frequency ranges, so that when the dual-band filter operates in one frequency band, the impedance mismatch effect caused by the filter in the other frequency band is suppressed, thereby enabling the dual-band filter to have good return loss in both frequency bands.

[0030] At the same time, the first dielectric waveguide power divider, the second dielectric waveguide power divider, the first dielectric waveguide filter, the second dielectric waveguide filter, and the impedance matching structure of the present invention are integrated on the same piece of ceramic. The overall structure adopts an integrated design, which greatly reduces the production cost of the device and reduces the size of the device compared with the existing technology.

[0031] (2) Furthermore, the two inductive coupling structures are coupling structures formed by coupling slots and shallow blind holes, which can be equivalent to a series structure of capacitors and inductors, and the inductive reactance of the inductor is greater than the capacitive reactance of the capacitor. The two capacitive coupling structures are coupling structures formed by coupling slots and deep blind holes, which can be equivalent to a series structure of capacitors and inductors, and the capacitive reactance of the capacitor is greater than the inductive reactance of the inductor. Such a design can effectively improve the return loss in the two passbands of the dual-band filter.

[0032] (3) Furthermore, the microwave ceramic waveguide dual-frequency filter of the present invention uses TE 10 Compared with the TEM mode adopted by the prior art filter transmission signal using coaxial or microstrip structure, the transmission signal of the present invention adopts TE 10 mode, with lower transmission loss.

[0033] In summary, the integrated microwave ceramic waveguide dual-band filter of the present invention realizes the integrated design of waveguide power divider, impedance matching network and filter, which reduces the volume of the dual-band filter, reduces device loss, and reduces device cost, meeting the application requirements of 5G communication base stations. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a schematic diagram of the topological structure of an integrated dual-band filter formed by two six-cavity double-zero ceramic waveguide filters provided in Example 1 of the present invention.

[0035] Figure 2 This is a schematic diagram of the three-dimensional structure of an integrated dual-band filter formed by two six-cavity double-zero-point ceramic waveguide filters provided in Example 1 of the present invention.

[0036] Figure 3 This is a schematic diagram of the upper surface structure of an integrated dual-band filter formed by two six-cavity double-zero ceramic waveguide filters provided in Example 1 of the present invention.

[0037] Figure 4 This is a schematic diagram of the lower surface structure of an integrated dual-band filter formed by two six-cavity double-zero-point ceramic waveguide filters provided in Example 1 of the present invention.

[0038] Figure 5 1 is a schematic diagram of simulation results of reflection coefficient and transmission coefficient of an integrated dual-band filter composed of two six-cavity double-zero ceramic waveguide filters provided in Example 1 of the present invention.

[0039] Figure 6 This is a schematic diagram of the topological structure of an integrated dual-band filter provided by Example 2 of the present invention, which is composed of two eight-cavity four-zero-point ceramic waveguide filters.

[0040] Figure 7 This is a schematic diagram of the three-dimensional structure of an integrated dual-band filter provided by Example 2 of the present invention, which is composed of two eight-cavity four-zero-point ceramic waveguide filters.

[0041] Figure 8 This is a schematic diagram of the upper surface structure of an integrated dual-band filter composed of two eight-cavity four-zero-point ceramic waveguide filters provided in Example 2 of the present invention.

[0042] Figure 9This is a schematic diagram of the lower surface structure of an integrated dual-band filter composed of two eight-cavity four-zero-point ceramic waveguide filters provided in Example 2 of the present invention.

[0043] Figure 10 1 is a schematic diagram of simulation results of reflection coefficient and transmission coefficient of an integrated dual-band filter composed of two eight-cavity four-zero ceramic waveguide filters provided in Example 2 of the present invention.

[0044] Throughout the drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0045] 1 is a ceramic dielectric body, 2 is a first dielectric waveguide power divider, 3 is a first dielectric waveguide filter, 4 is a second dielectric waveguide power divider, and 5 is a second dielectric waveguide filter. DETAILED DESCRIPTION

[0046] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only intended to illustrate the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0047] In the present invention, the terms "first", "second", etc. in the present invention and the accompanying drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0048] like Figure 1 As shown, the present invention provides an integrated microwave ceramic waveguide dual-band filter, comprising: a ceramic dielectric body 1, two dielectric waveguide power dividers, two dielectric waveguide filters, and an impedance matching structure integrated on the ceramic dielectric body. The outer surface of the ceramic dielectric body 1 is plated with a conductive metal layer.

[0049] The two dielectric waveguide power dividers are respectively a first dielectric waveguide power divider 2 and a second dielectric waveguide power divider 4 . The first dielectric waveguide power divider includes one input end and two output ends, and the second dielectric waveguide power divider includes two input ends and one output end.

[0050] The two dielectric waveguide filters are respectively referred to as a first dielectric waveguide filter 3 and a second dielectric waveguide filter 5 .

[0051] The impedance matching structure is used to achieve a matching connection between two dielectric waveguide power dividers and two dielectric waveguide filters, suppress the impedance mismatch caused by the parallel connection of the two filters, and achieve excellent return loss characteristics in two passbands. The impedance matching structure includes two coupling slots, two shallow blind holes a1, and two deep blind holes a2. The two coupling slots are denoted as the first coupling slot b1 and the second coupling slot b2, the two shallow blind holes are denoted as the first shallow blind hole and the second shallow blind hole, and the two deep blind holes are denoted as the first deep blind hole and the second deep blind hole. The two shallow blind holes have the same depth, and the two deep blind holes have the same depth. The first coupling slot and the first shallow blind hole form a first inductive coupling structure, the first coupling slot and the second shallow blind hole form a second inductive coupling structure, the second coupling slot and the first deep blind hole form a first capacitive coupling structure, and the second coupling slot and the second deep blind hole form a second capacitive coupling structure.

[0052] The input end of the first dielectric waveguide power divider 2 serves as the input end of the dual-band filter and is connected to an external circuit. The first output end of the first dielectric waveguide power divider 2 is coupled to the first dielectric waveguide filter 3 via a first inductive coupling structure formed by a first coupling slot and a first shallow blind via, and the second output end is coupled to the second dielectric waveguide filter 5 via a first capacitive coupling structure formed by a second coupling slot and a first deep blind via. The first input end of the second dielectric waveguide power divider 4 is coupled to the first dielectric waveguide filter 3 via a second inductive coupling structure formed by a first coupling slot and a second shallow blind via, and the second input end is coupled to the second dielectric waveguide filter 5 via a second capacitive coupling structure formed by a second coupling slot and a second deep blind via. The output end of the second dielectric waveguide power divider 5 serves as the output end of the dual-band filter and is connected to an external circuit. The center frequency of the first dielectric waveguide filter 3 is lower than the center frequency of the second dielectric waveguide filter 5. In this embodiment, the first dielectric waveguide filter 3 functions as a low-frequency band filter, and the second dielectric waveguide filter 5 functions as a high-frequency band filter.

[0053] The first inductive coupling structure formed by the first coupling slot and the first shallow blind hole, and the second inductive coupling structure formed by the first coupling slot and the second shallow blind hole can both be equivalent to a series structure of a capacitor and an inductor, and the inductive reactance of the inductor is greater than the capacitive reactance of the capacitor;

[0054] The first capacitive coupling structure formed by the second coupling slot and the first deep blind hole and the second capacitive coupling structure formed by the second coupling slot and the second deep blind hole can both be equivalent to a capacitor and an inductor series structure, and the capacitive reactance of the capacitor is greater than the inductive reactance of the inductor.

[0055] An impedance matching structure is set between the two dielectric waveguide power dividers and the two dielectric waveguide filters. The impedance matching structure can be equivalent to a series structure of capacitors and inductors. When the dual-band filter operates in one frequency band, the impedance mismatch caused by the filter in the other frequency band is suppressed, thereby improving the return loss of the device in the two frequency bands.

[0056] In this embodiment, both dielectric waveguide power dividers are H-plane T-type dielectric waveguide power dividers. A rectangular impedance matching groove is provided on the T-type dielectric waveguide power divider, which is used to output the input signal with equal amplitude and phase at the two output branches of the T-type dielectric waveguide power divider. The rectangular impedance matching groove is located at the center of the narrow wall of the branch waveguide of the T-type dielectric waveguide power divider and at the connection between the branch waveguide and the main waveguide, and is used to achieve impedance matching of the power divider within a wider frequency band. The main waveguide is a waveguide connected to an external circuit to realize signal input and output, and the branch waveguide is a waveguide connected to the filter, that is, the input end of the first dielectric waveguide power divider and the output end of the second dielectric waveguide power divider are main waveguides, and the two output ends of the first dielectric waveguide power divider and the two input ends of the second dielectric waveguide power divider are branch waveguides.

[0057] The two dielectric waveguide filters include a capacitive CQ coupling structure for generating a pair of transmission zero points with adjustable positions outside the passband of the filter to improve the out-of-band suppression characteristics.

[0058] The upper surfaces of the two dielectric waveguide filters are provided with tuning holes, which independently form a resonant cavity with part of the body. The tuning holes are all blind holes and are used to adjust the resonant frequency of the cavity.

[0059] The two dielectric waveguide filters are respectively provided with coupling slots, which are rectangular slots located at the connection of the resonant cavities and are used to adjust the inductive coupling amount between the resonant cavities to achieve inductive coupling.

[0060] The two dielectric waveguide filters are respectively provided with negative coupling blind holes, which are capacitive coupling blind holes. The capacitive coupling between the resonant cavities is adjusted by adjusting the depth of the blind holes.

[0061] Both dielectric waveguide filters are ceramic waveguide filters.

[0062] The solution of the present invention is further described below with reference to two specific embodiments.

[0063] Example 1

[0064] like Figure 1 As shown, in this embodiment, the two dielectric waveguide filters are two six-cavity double-zero ceramic waveguide filters, respectively. The integrated dual-band filter is composed of two six-cavity double-zero ceramic waveguide filters. In the figure, L represents a low-frequency band filter, H represents a high-frequency band filter, the solid line connection between the resonant cavities represents inductive coupling, and the dotted line connection between the resonant cavities represents capacitive coupling.

[0065] Its appearance and structure are as follows Figure 2-4As shown, the H-plane T-type waveguide power splitter is equipped with rectangular slots B2 and B4 with a set length and width to adjust the return loss of the power splitter input port within the operating frequency range, achieving a good matching state within the operating frequency range. One branch of the waveguide power splitter is connected to the low-band filter via a coupling slot b1 and a coupling hole a1. The coupling slot is a rectangular slot with a set length, width, and height, and the coupling hole is a shallow blind hole. It is used to adjust the inductive coupling with the low-band filter, introducing an equivalent inductor and capacitor series structure with a greater inductive reactance than the capacitive reactance, thereby suppressing the impedance mismatch caused by the high-band filter. The coupling slot b2 and coupling hole a2 are located at the connection between the other branch of the waveguide power splitter and the high-band filter. They are used to adjust the capacitive coupling between the waveguide power splitter and the high-band filter, introducing an equivalent inductor and capacitor series structure with a greater capacitive reactance than the inductive reactance, thereby suppressing the impedance mismatch caused by the low-band filter. The coupling hole a2 is a deep blind hole.

[0066] The filter's top surface features tuning holes A1 and A3. These holes, along with a portion of the ceramic block, form independent resonant cavities. Changing the depth of the tuning holes adjusts the resonant frequency of the cavities. Coupling slots B1 and B3 are located between the resonant cavities. These rectangular slots, with set lengths, widths, and heights, are used to achieve inductive coupling between the cavities. Capacitive coupling between the cavities is achieved through coupling holes A2 and A4, with the strength of the capacitive coupling adjusted by varying the hole depth. The second, third, fourth, and fifth resonant cavities of the two filters each form a capacitive CQ coupling unit, introducing a pair of transmission zeros outside the two passbands. The positions of these transmission zeros can be adjusted by varying the amount of cross-coupling.

[0067] The reflection coefficient curve and transmission coefficient curve of the above ceramic waveguide dual-band filter are as follows: Figure 5 As shown in the figure, S11 and S21 represent the reflection coefficient and transmission coefficient respectively. It can be seen from the figure that the dual-band filter can achieve two frequency bands of 2.595 GHz and 3.5 GHz, and the return loss in the two passbands is below -18.5 dB.

[0068] Example 2

[0069] The difference from Example 1 is that the two dielectric waveguide filters are two eight-cavity four-zero-point ceramic waveguide filters. The integrated dual-band filter is composed of two eight-cavity four-zero-point ceramic waveguide filters. Its circuit topology is as follows: Figure 6 As shown, the appearance structure is as Figure 7-9As shown. Blind holes A2 and A5 are used to adjust the resonant frequency of the resonant cavity, rectangular slots B1 and B3 are used to achieve inductive coupling between the resonant cavities, and blind holes A1, A3, A4, and A6 achieve capacitive coupling between the resonant cavities. The first, second, third, and fourth resonant cavities and the fifth, sixth, seventh, and eighth resonant cavities of each filter form a CQ coupling structure, introducing two pairs of transmission zeros outside the passband. The same as Example 1 is that the power divider of this embodiment also has matching slots B2 and B4, so that the power divider has good matching within a wider frequency range; similarly, the impedance matching structures a1, a1 and b1, b2 between the power divider and the filter are inductively and capacitively coupled with the low-frequency band filter and the high-frequency band filter, respectively, introducing an equivalent inductor and capacitor series structure to achieve impedance matching in the two frequency bands and improve the return loss in the two passbands.

[0070] The reflection coefficient curve and transmission coefficient curve of this embodiment are as follows: Figure 10 As shown, two frequency bands, 2.595 GHz and 3.5 GHz, can be achieved, with return losses in the passbands of -19.6 dB and -19.0 dB respectively. There are two pairs of transmission zeros outside each passband, and their positions can be controlled by adjusting the cross-coupling amount.

[0071] The first dielectric waveguide power divider, the second dielectric waveguide power divider, the first dielectric waveguide filter, the second dielectric waveguide filter, and the impedance matching structure of the present invention are integrated on the same piece of ceramic. The overall structure adopts an integrated design. Compared with the existing technology, it facilitates subsequent processing and manufacturing, greatly reduces the production cost of the device, and reduces the size of the device.

[0072] The impedance matching network of the present invention suppresses the impedance mismatch caused by the parallel connection of two filters by arranging shallow and deep blind holes and coupling slots on the ceramic block for equivalent replacement, thereby achieving excellent return loss performance in two passbands.

[0073] The microwave ceramic waveguide dual-frequency filter of the present invention transmits microwave signals using TE 10 Compared with the TEM mode adopted by the prior art for transmitting microwave signals using filters with coaxial or microstrip structures, the transmission signal of the present invention adopts TE 10 mode, with lower transmission loss.

[0074] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An integrated microwave ceramic waveguide dual-band filter, characterized in that: include: A ceramic dielectric body and a first dielectric waveguide power divider, a second dielectric waveguide power divider, a first dielectric waveguide filter, a second dielectric waveguide filter and an impedance matching structure integrated on the ceramic dielectric body; The first dielectric waveguide power divider includes an input end and two output ends, and the second dielectric waveguide power divider includes two input ends and one output end; the impedance matching structure includes a first inductive coupling structure, a second inductive coupling structure, a first capacitive coupling structure, and a second capacitive coupling structure; The first output end of the first dielectric waveguide power divider is coupled to the first dielectric waveguide filter via a first inductive coupling structure, and the second output end is coupled to the second dielectric waveguide filter via a first capacitive coupling structure; The first input end of the second dielectric waveguide power divider is coupled to the first dielectric waveguide filter via a second inductive coupling structure, and the second input end is coupled to the second dielectric waveguide filter via a second capacitive coupling structure; The center frequency of the first dielectric waveguide filter is lower than the center frequency of the second dielectric waveguide filter; the input end of the first dielectric waveguide power divider and the output end of the second dielectric waveguide power divider are respectively used as the input end and output end of the dual-band filter to connect to an external circuit.

2. The integrated microwave ceramic waveguide dual-band filter according to claim 1, characterized in that: The first inductive coupling structure is a coupling structure formed by a first coupling groove and a first shallow blind hole; The second inductive coupling structure is a coupling structure formed by the first coupling groove and the second shallow blind hole; The first capacitive coupling structure is a coupling structure formed by the second coupling groove and the first deep blind hole; The second capacitive coupling structure is a coupling structure formed by a second coupling groove and a second deep blind hole.

3. The integrated microwave ceramic waveguide dual-band filter according to claim 2, characterized in that: The first inductive coupling structure and the second inductive coupling structure are both equivalent to a capacitor and an inductor in series structure, and the inductive reactance of the inductor is greater than the capacitive reactance of the capacitor; The first capacitive coupling structure and the second capacitive coupling structure are both equivalent to a capacitor and an inductor in series structure, and the capacitive reactance of the capacitor is greater than the inductive reactance of the inductor.

4. The integrated microwave ceramic waveguide dual-band filter according to claim 1, characterized in that: The two dielectric waveguide power dividers are both H-plane T-type dielectric waveguide power dividers.

5. The integrated microwave ceramic waveguide dual-band filter according to claim 4, characterized in that: A rectangular impedance matching slot is provided on the H-plane T-shaped dielectric waveguide power divider.

6. The integrated microwave ceramic waveguide dual-band filter according to claim 1, characterized in that: The two dielectric waveguide filters both include a capacitive CQ coupling structure for generating a pair of position-adjustable transmission zero points outside the passband of the filter.

7. The integrated microwave ceramic waveguide dual-band filter according to claim 1, characterized in that: The surfaces of the two dielectric waveguide filters are provided with tuning holes, coupling slots and capacitive coupling blind holes; The tuning hole is a blind hole for adjusting the resonant frequency of the resonant cavity; the coupling slot is a rectangular slot for adjusting the inductive coupling between the resonant cavities; and the capacitive coupling blind hole is used to form a capacitive CQ coupling structure in the filter.

8. The integrated microwave ceramic waveguide dual-band filter according to claim 1, characterized in that: The two dielectric waveguide filters are both ceramic waveguide filters.

9. The integrated microwave ceramic waveguide dual-band filter according to claim 1, characterized in that: The outer surface of the ceramic medium body is plated with a conductive metal layer.

10. The integrated microwave ceramic waveguide dual-band filter according to any one of claims 1 to 9, characterized in that: The microwave signal of the dual-frequency filter is TE 10 mode for transmission.

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