Substrate integrated waveguide filter structure based on mixed structure and design method

Abstract

The invention discloses a substrate integrated waveguide filter structure based on a mixed structure and a design method, and the structure comprises a bottom plate, a first dielectric substrate, a middle layer, a second dielectric substrate and a top plate, the stripline resonator includes a U-shaped half-wavelength stripline resonator or a combination of a U-shaped half-wavelength stripline resonator and a full-wavelength stripline resonator. A main body of the U-shaped half-wavelength strip line resonator is of a U-shaped structure, blind holes are formed in the two ends of the U-shaped half-wavelength strip line resonator, the U-shaped half-wavelength strip line resonator is arranged on the upper portion, the middle portion or the lower portion of the common wall, and the middle point of the U-shaped half-wavelength strip line resonator is located on the common The U-shaped half-wavelength strip line resonator is arranged, the position of the U-shaped half-wavelength strip line resonator can be flexibly arranged, the structure of the U-shaped half-wavelength strip line resonator is more compact, miniaturization of the filter is effectively achieved, the coupling strength of the U-shaped half-wavelength strip line resonator and the cavity of the SIW resonator can be well controlled by adjusting the bending degree of the U-shaped half-wavelength strip line resonator. The method is suitable for various wireless communication systems.

Description

Technical Field

[0001] The present invention relates to the field of microwave technology, and particularly to a substrate integrated waveguide filter structure and design method based on a hybrid structure. Background Art

[0002] A microwave filter is a device designed to selectively transmit or attenuate signals of specific frequencies, which can optimize system performance, reduce interference, and improve the quality of signal transmission. Microwave filters are widely used in multiple fields, including wireless communication systems, radar systems, radio frequency front-end processing, and satellite communication, etc. Particularly, it relates to a substrate integrated waveguide (SIW) filter with a hybrid structure, which has smaller size, higher quality factor, lower insertion loss, better shielding characteristics, and more transmission zeros compared with traditional filters, and is applicable to various wireless communication systems and application scenarios.

[0003] Microwave filters stem from the requirements of wireless communication systems and radar technology, especially the strict requirements for signal quality and frequency selectivity during the transmission and reception of high-frequency signals. With the development of wireless communication technology, it has become particularly important to design bandpass filters (BPFs) with small size, low insertion loss (IL), and controllable transmission zeros (TZ). Filter designs using SIW technology are widely applied in filter design due to their advantages such as low loss, high quality factor (Q), light weight, and easy integration. However, the sizes of these filters are relatively large. Using a hybrid structure for filters is a good way to achieve miniaturization, and these structures can be realized by combining SIW cavities with other planar resonators. However, the following problems still exist in the prior art: 1. The number of transmission zeros of the filter is small, the order is low, and the selectivity is poor. Although the hybrid SIW filter can effectively achieve miniaturization, the number of transmission zeros is small and their positions are not easy to control, making it difficult to achieve high order.

[0004] 2. The loss of the filter is high: To achieve the miniaturization of the hybrid SIW filter, semi-open structures are usually used, and these semi-open structures will reduce the quality factor of the SIW resonator, thereby increasing the insertion loss.

[0005] 3. The size of the filter is large: The SIW filter is larger in size than the microstrip filter, and high-order filters usually require multiple resonators to be cascaded to achieve the required filtering characteristics, and the overall size is usually large.

[0006] 4. The influence of the stripline resonator on the SIW resonator is large: The coupling strength between the traditional straight stripline and the SIW cavity is not easy to control, and the perturbation to the SIW resonator is large, so it is not easy to be used as a resonator. Summary of the Invention

[0007] In order to solve the problems of the existing filters, such as few transmission zeros, high loss, large filter size, and great influence of stripline resonators on SIW resonators, the present invention provides a substrate integrated waveguide filter structure and a design method based on a hybrid structure. The present invention increases the number of transmission zeros, embeds multiple stripline resonators into two SIW resonators on the left and right, and its size is reduced by 60% compared with the traditional SIW filter, effectively realizing miniaturization, and the structure is more compact, reducing loss. Finally, the present invention uses a U-shaped stripline as a resonator, and the coupling strength between the U-shaped half-wavelength stripline resonator and the cavity of the SIW resonator can be well controlled, which is applicable to various wireless communication systems.

[0008] In order to achieve the above object, the technical solution of the present invention is as follows: The present invention, in a first aspect, proposes a substrate integrated waveguide filter structure based on a hybrid structure, including a bottom plate, a first dielectric substrate, an intermediate layer, a second dielectric substrate, and a top plate. The bottom plate, the first dielectric substrate, the intermediate layer, the second dielectric substrate, and the top plate are arranged in sequence from bottom to top. The first dielectric substrate, the second dielectric substrate, and the top plate are respectively provided with via hole arrays. The bottom plate, the first dielectric substrate, the second dielectric substrate, the via hole arrays, and the top plate form two SIW resonators. The two SIW resonators are symmetrically distributed left and right. The adjacent sides of the two SIW resonators form a common wall. The feature is that the intermediate layer includes at least one stripline resonator, and the stripline resonator includes a U-shaped half-wavelength stripline resonator or a combination of a U-shaped half-wavelength stripline resonator and a full-wavelength strip resonator; this structure forms a multi-layer structure through the bottom plate, the first dielectric substrate, the intermediate layer, the second dielectric substrate, and the top plate, and forms two SIW resonators through the via hole arrays and the intermediate layer. The use of the U-shaped half-wavelength stripline resonator makes the overall structure compact, does not occupy extra space, effectively realizes miniaturization, and different-order filters such as third-order and fifth-order can be constructed according to this structure and different requirements; The main body of the U-shaped half-wavelength stripline resonator is in a U-shaped structure. Blind holes are provided at both ends of the U-shaped half-wavelength stripline resonator. The blind holes are located on the first dielectric substrate and penetrate the first dielectric substrate. The U-shaped half-wavelength stripline resonator is arranged on the upper, middle, or lower part of the common wall, and the midpoint of the U-shaped half-wavelength stripline resonator is located on the common wall; by setting the U-shaped half-wavelength stripline resonator, the overall structure is compact, and its position can be arbitrarily set on the upper, middle, or lower part of the common wall, the setting method is flexible, and the short circuit of both ends of the U-shaped half-wavelength stripline resonator is realized through the blind hole setting; The via array includes a plurality of vias, the vias are circular holes, and the plurality of vias are arranged near the edges of the first dielectric substrate, the second dielectric substrate and the top plate and at the position of the common wall. The vias vertically penetrate through the first dielectric substrate, the second dielectric substrate and the top plate. There is a gap at the position of the common wall in the via array. According to the position of the gap, it is divided into an upper array and a lower array. The upper array is an E shape arranged horizontally, and the lower array is an E shape that is a mirror image of the E shape arranged horizontally of the upper array, which is convenient for constructing two SIW resonators.

[0009] Further, the top plate includes a rectangular plate and two feed lines. One feed line is arranged on each of the left and right sides of the rectangular plate. The rectangular plate and the two feed lines are an integral structure. Two horizontally arranged L-shaped holes are opened at the connection between the feed line and the top plate. The two horizontally arranged L-shaped holes are respectively located on the upper and lower sides of the connection between the feed line and the top plate. The vertical section of the upper horizontally arranged L-shaped hole faces upward, and the vertical section of the lower horizontally arranged L-shaped hole faces downward; There is a gap between the vias of the upper array and the vias of the lower array at the position of the top plate corresponding to the L-shaped hole.

[0010] The second aspect of the present invention proposes a design method for a substrate integrated waveguide filter structure based on a hybrid structure, including: Step 1: Determine the materials of the first dielectric substrate and the second dielectric substrate based on the relative dielectric constant, loss tangent and cost, and set the operating frequency and order of the filter; Step 2: Set the number of required resonators according to the order of the filter, and calculate the sizes of the SIW resonator and the stripline resonator according to the operating frequency of the filter; Step 3: Set the equivalent topological structure of the filter and the coupling matrix corresponding to the equivalent topological structure, and determine the coupling coefficients between the resonators, the response of the coupling matrix, and the number and shape of the stripline resonators according to requirements; Step 4: Establish a simulation model of the hybrid substrate integrated waveguide filter, and optimize the simulation model to make the performance of the filter meet the requirements.

[0011] Step 5: Verify the theory by comparing the simulation results with the response of the coupling matrix, and complete the construction of the substrate integrated waveguide filter based on the hybrid structure.

[0012] Through this method, the actual requirements of the filter can be ensured, and the order and structure of the filter can be flexibly designed, which is applicable to different requirements and scenarios.

[0013] In the third aspect of the present invention, a directly coupled third-order hybrid SIW filter is proposed, which adopts the hybrid structure substrate integrated waveguide bandpass filter structure described in the first aspect. The stripline resonator includes a U-shaped half-wavelength stripline resonator, and the U-shaped half-wavelength stripline resonator includes a U-shaped stripline and blind vias. Blind vias are connected to both ends of the U-shaped stripline, and each blind via vertically penetrates the first dielectric substrate. The two blind vias are symmetrically distributed along the common wall. The two SIW resonators and the U-shaped half-wavelength stripline resonator form a main coupling path.

[0014] For the above directly coupled third-order hybrid SIW filter, the stripline resonator is embedded in the left and right SIW resonators without occupying additional space, reducing the size. Moreover, by using a U-shaped stripline as the resonator, the coupling strength can be well controlled, which is suitable for various wireless communication systems.

[0015] In the fourth aspect of the present invention, a fifth-order hybrid SIW filter based on a box-shaped topology structure is proposed, which adopts the hybrid structure substrate integrated waveguide bandpass filter structure described in the first aspect. The stripline resonator includes a combination of a U-shaped half-wavelength stripline resonator and two full-wavelength stripline resonators. The U-shaped half-wavelength stripline resonator includes a U-shaped stripline and blind vias. Blind vias are connected to both ends of the U-shaped stripline, and each blind via vertically penetrates the first dielectric substrate, facilitating the short-circuiting of both ends of the U-shaped half-wavelength stripline resonator. The two full-wavelength stripline resonators are respectively arranged in parallel on the upper and lower sides of the U-shaped half-wavelength stripline resonator. The midpoints of the two full-wavelength stripline resonators are located on the common wall. Each full-wavelength stripline resonator includes a stripline and blind vias. Blind vias are provided at both ends of the stripline, and the stripline is connected to the blind vias, facilitating the short-circuiting of both ends of the full-wavelength stripline resonator through the blind vias. The two SIW resonators, the U-shaped half-wavelength stripline resonator, and the two full-wavelength stripline resonators form four transmission zeros, three main coupling paths, and one cross-coupling path.

[0016] The fifth-order hybrid SIW filter based on the box-shaped topology structure can generate four transmission zeros, and the positions of three of the transmission zeros can be well controlled, effectively improving the performance of the stopband. Moreover, the three stripline resonators do not occupy additional space, effectively achieving miniaturization.

[0017] Advantages of the present invention: (1) The hybrid SIW filter of the present invention uses a U-shaped stripline as the resonator, and the coupling strength can be well controlled, which is suitable for various wireless communication systems.

[0018] (2) The present invention is also realized by embedding at least one U-shaped half-wavelength strip resonator into the left and right SIW resonators. It does not occupy additional space, and the size is reduced by 60% compared with the traditional SIW filter, effectively achieving miniaturization and reducing losses.

[0019] (3) The present invention proposes a fifth-order hybrid SIW filter based on a box-shaped topological structure on the basis of a substrate integrated waveguide filter structure with a hybrid structure. Its overall structure is compact and has four position-controllable TZs, achieving high selectivity. The hybrid SIW filter of the present invention can generate four transmission zeros through coupling, and the positions of three transmission zeros can be well controlled, which can effectively improve the performance of the stopband. Description of the Drawings

[0020] Figure 1 Schematic diagram of the substrate integrated waveguide filter structure with a hybrid structure provided by an embodiment of the present invention.

[0021] Figure 2 Schematic diagram of the equivalent topological structure of the directly-coupled third-order hybrid SIW filter provided by an embodiment of the present invention.

[0022] Figure 3 Schematic diagram of the directly-coupled third-order hybrid SIW filter provided by an embodiment of the present invention.

[0023] Figure 4 Schematic diagram of the electric field distribution at the center frequency of the directly-coupled third-order hybrid SIW filter provided by an embodiment of the present invention.

[0024] Figure 5 Schematic diagram of the response curve of the directly-coupled third-order hybrid SIW filter provided by an embodiment of the present invention.

[0025] Figure 6 Schematic diagram of the fifth-order hybrid SIW filter based on a box-shaped topological structure provided by an embodiment of the present invention.

[0026] Figure 7 Schematic diagram of the equivalent topological structure of the fifth-order hybrid SIW filter based on a box-shaped topological structure provided by an embodiment of the present invention.

[0027] Figure 8 Schematic diagram of the electric field distribution at the center frequency of the fifth-order hybrid SIW filter based on a box-shaped topological structure provided by an embodiment of the present invention.

[0028] Figure 9 Schematic diagram of the response curve of the fifth-order hybrid SIW filter based on a box-shaped topological structure provided by an embodiment of the present invention.

[0029] The reference numerals in the drawings are: 1 is the top plate, 2 is the second dielectric substrate, 3 is the U-shaped half-wavelength stripline resonator, 4 is the first dielectric substrate, 5 is the bottom plate, 6 is the via array, 7 is the blind via, 8 is the feeder, 9 is the L-shaped hole, 10 is the full-wavelength stripline, 11 is the mounting hole, 12 is the intermediate layer, 13 is the SIW resonator, and 14 is the common wall. Detailed implementation mode

[0030] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0031] Embodiment 1 As Figure 1 shown, a substrate integrated waveguide filter structure based on a hybrid structure includes a bottom plate 5, a first dielectric substrate 4, an intermediate layer 12, a second dielectric substrate 2, and a top plate 1. The bottom plate 5, the first dielectric substrate 4, the intermediate layer 12, the second dielectric substrate 2, and the top plate 1 are arranged in sequence from bottom to top. Specifically, the bottom plate 5 is a rectangular plate made of copper with a copper plating thickness of 0.035 mm. The intermediate layer 12 and the top plate 1 are also made of copper with copper plating thicknesses of 0.07 mm and 0.035 mm respectively. The first dielectric substrate 4 and the second dielectric substrate 2 are both rectangular plates made of Taconic TLY-5 material with a thickness of 0.508 mm, a relative dielectric constant of 2.2, and a loss tangent of 0.0008.

[0032] The top plate 1 includes a rectangular plate and two feeders 8. One feeder 8 is arranged on each of the left and right sides of the rectangular plate. The rectangular plate and the two feeders 8 are an integral structure. Two horizontally arranged L-shaped holes 9 are opened at the connection between the feeder 8 and the top plate 1. The two horizontally arranged L-shaped holes 9 are respectively located on the upper and lower sides of the connection between the feeder 8 and the top plate 1. The vertical section of the upper horizontally arranged L-shaped hole 9 faces upward, and the vertical section of the lower horizontally arranged L-shaped hole 9 faces downward.

[0033] The first dielectric substrate 4, the second dielectric substrate 2, and the top plate 1 are correspondingly provided with a via array 6. The via array 6 includes a plurality of vias. The vias are circular holes. The plurality of vias are opened near the edges of the first dielectric substrate 4, the second dielectric substrate 2, and the top plate 1 and the position of the common wall 14. The vias vertically penetrate the first dielectric substrate 4, the second dielectric substrate 2, and the top plate 1. A gap is left at the position of the common wall 14 in the via array 6. According to the gap position, it is divided into an upper array and a lower array. The upper array is an E-shaped arranged horizontally, and the lower array is an E-shaped that is a mirror image of the E-shaped arranged horizontally of the upper array.

[0034] There is a gap between the vias in the upper array and the vias in the lower array at the position of the top plate 1 corresponding to the L-shaped hole 9.

[0035] The bottom plate 5, the first dielectric substrate 4, the second dielectric substrate 2, the via array 6, and the top plate 1 form two SIW resonators 13. The two SIW resonators 13 are symmetrically distributed left and right. The adjacent sides of the two SIW resonators 13 form a common wall 14. The middle layer 12 includes at least one strip line resonator. The strip line resonator includes a U-shaped half-wavelength strip line resonator 3 or a combination of a U-shaped half-wavelength strip line resonator 3 and a full-wavelength strip resonator 10. Specifically, the main body of the U-shaped half-wavelength strip line resonator 3 has a U-shaped structure, making the overall structure compact and facilitating the miniaturization of the filter. Blind holes 7 are provided at both ends of the U-shaped half-wavelength strip line resonator 3. The blind holes 7 are located on the first dielectric substrate 4 and penetrate the first dielectric substrate 4, facilitating the short-circuiting of both ends of the U-shaped half-wavelength strip line resonator 3. The U-shaped half-wavelength strip line resonator 3 is disposed at the upper, middle, or lower part of the common wall 14, and the midpoint of the U-shaped half-wavelength strip line resonator 3 is located on the common wall 14. The flexible setting position of the U-shaped half-wavelength strip line resonator 3 can well meet the actual requirements, and the structure is compact, reducing losses and facilitating the miniaturization of the filter.

[0036] Embodiment 2 Based on the above embodiment, the present invention proposes a design method for a substrate integrated waveguide filter structure based on a hybrid structure, including: Step 1: Determine the materials of the first dielectric substrate 4 and the second dielectric substrate 2 based on the relative dielectric constant, loss tangent, and cost, and set the operating frequency and order of the filter.

[0037] Step 2: Set the number of required resonators according to the order of the filter, and calculate the sizes of the SIW resonator and the strip line resonator according to the operating frequency of the filter.

[0038] Step 3: Set the equivalent topological structure of the filter and the coupling matrix corresponding to the equivalent topological structure, and determine the coupling coefficients between the resonators, the response of the coupling matrix, and the number and shape of the strip line resonators according to the requirements.

[0039] Step 4: Establish a simulation model of the hybrid substrate integrated waveguide filter, and optimize the simulation model to make the performance of the filter meet the requirements.

[0040] Step 5: Verify the theory by comparing the simulation results with the response of the coupling matrix, and complete the construction of the substrate integrated waveguide filter based on the hybrid structure.

[0041] This method determines the material of the dielectric substrate, the operating frequency and the order of the filter according to the actual requirements. Then, the number and size of the resonators are obtained based on the order and the operating frequency. The equivalent topological structure of the filter and the coupling matrix corresponding to the equivalent topological structure are set, and the relevant data are obtained. Finally, simulation optimization is carried out to complete the design and construction of the substrate integrated waveguide filter based on the hybrid structure.

[0042] Example 3 Based on the above embodiments, as Figure 2 and Figure 3 shown, the present invention proposes a directly coupled third-order hybrid SIW filter (Filter Ⅰ), which adopts a hybrid structure substrate integrated waveguide bandpass filter structure in Example 1. The stripline resonator includes a U-shaped half-wavelength stripline resonator 3. The U-shaped half-wavelength stripline resonator 3 includes a U-shaped stripline and blind vias 7. Blind vias 7 are connected to both ends of the U-shaped stripline, which is convenient for short-circuiting both ends of the U-shaped half-wavelength stripline resonator 3. The midpoint of the U-shaped half-wavelength stripline resonator 3 is located on the common wall 14, and the two blind vias 7 are symmetrically distributed along the common wall 14. Two SIW resonators 13 and the U-shaped half-wavelength stripline resonator 3 form a main coupling path.

[0043] Specifically, Filter Ⅰ is realized by combining a U-shaped half-wavelength stripline resonator 3 (UHWSLR) with two SIW resonators 13. As Figure 3 shown, the two SIW resonators 13 on the left and right operate in the TE101 mode, and the UHWSLR operates in the fundamental mode. Compared with the straight stripline resonator, the UHWSLR has a compact structure and can be flexibly embedded into various resonators. As Figure 3 shown, and the coupling strength between the UHWSLR and the SIW resonator 13 can be controlled by the bending degree ( ) of the UHWSLR and . Among them, is the bending length of the stripline resonator, is the bottom length of the stripline resonator, and is the distance from the bottom of the stripline resonator to the transverse midline of the top plate 1. The center frequency of Filter Ⅰ is 9.27 GHz, the 3-dB relative bandwidth is 11.33%, and the insertion loss is -1.1 dB. To intuitively show the effect of the directly coupled third-order hybrid SIW filter, the present invention gives the electric field distribution at the center frequency of the directly coupled third-order hybrid SIW filter, as Figure 4 shown, and the response curve of the directly coupled third-order hybrid SIW filter as Figure 5 shown.

[0044] Example 4 Based on the above embodiments, as Figure 6As shown in the figure, the present invention proposes a fifth-order hybrid SIW filter (Fiter Ⅱ) based on a box-shaped topological structure, including: Adopt a hybrid structure substrate integrated waveguide bandpass filter structure in Embodiment 1. The stripline resonator includes a combination of a U-shaped half-wavelength stripline resonator 3 and two full-wavelength stripline resonators 10. The U-shaped half-wavelength stripline resonator 3 includes a U-shaped stripline and blind vias 7. Blind vias 7 are connected to both ends of the U-shaped stripline. Each blind via 7 vertically penetrates the first dielectric substrate 4, facilitating short-circuiting both ends of the U-shaped half-wavelength stripline resonator 3 through the blind vias 7.

[0045] The two full-wavelength stripline resonators 10 are respectively arranged in parallel on the upper and lower sides of the U-shaped half-wavelength stripline resonator 3. The midpoints of the two full-wavelength stripline resonators 10 are located on the common wall 14. Each full-wavelength stripline resonator 10 includes a stripline and blind vias 7. One blind via 7 is provided at both ends of the stripline, and the stripline is connected to the blind vias 7, facilitating short-circuiting both ends of the full-wavelength stripline resonator 10 through the blind vias 7. The two SIW resonators 13, the U-shaped half-wavelength stripline resonator 3 and the two full-wavelength stripline resonators 10 form four transmission zeros, three main coupling paths and one cross-coupling path.

[0046] Specifically, as Figure 7 shown, two full-wavelength stripline resonators 10 (FWSLRs) are added to Fiter Ⅱ on the basis of Filter Ⅰ. Both of the two FWSLRs operate in the first higher-order mode, and the UHWSLR operates in the fundamental mode. There are three main coupling paths in Fiter Ⅱ: 1-2-5, 1-3-5 and 1-4-5. Among them, 1-3-5 is the positive coupling path introduced by the UHWSLR, and 1-2-5 and 1-4-5 are the two negative coupling paths introduced by the upper and lower FWSLRs respectively. These two negative coupling paths can generate two transmission zeros (TZs) near the two passbands. The fundamental mode of the upper FWSLR serves as a non-resonant node, and this non-resonant node can generate a TZ in the lower stopband. And an additional TZ can be generated by the second higher-order mode of the FWSLR. Fiter Ⅱ can generate a total of four FTZs. The center frequency of Fiter Ⅱ is 9.26 GHz, the 3-dB relative bandwidth is 15.33%, and the insertion loss is -0.8 dB. To visually display the effect of the directly coupled third-order hybrid SIW filter, the present invention gives the electric field distribution at the center frequency of the fifth-order hybrid SIW filter based on the box-shaped topological structure, as Figure 8 shown, the response curve of the fifth-order hybrid SIW filter based on the box-shaped topological structure is as Figure 9 shown.

[0047] Preferably, the bottom plate 5, the first dielectric substrate 4, and the second dielectric substrate 2 may also be provided with a plurality of mounting holes 11 at uniform intervals around the periphery, facilitating the fixation of the filter.

[0048] In summary, the hybrid SIW filter of the present invention uses a U-shaped strip line as a resonator, and the coupling strength can be well controlled, which is suitable for various wireless communication systems. The present invention is also realized by embedding at least one U-shaped half-wavelength strip line resonator into the left and right two SIW resonators. It does not occupy extra space, and the size is reduced by 60% compared with the traditional SIW filter, effectively realizing miniaturization and reducing losses. The present invention proposes a fifth-order hybrid SIW filter based on a box-shaped topological structure on the basis of a hybrid-structure substrate integrated waveguide filter structure. Its overall structure is compact and has four position-controllable TZs, realizing high selectivity. The hybrid SIW filter of the present invention can generate four transmission zeros through coupling, and the positions of three transmission zeros can be well controlled, which can effectively improve the performance of the stopband.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. Substrate integrated waveguide filter structure based on a hybrid structure, comprising a bottom plate (5), a first dielectric substrate (4), an intermediate layer (12), a second dielectric substrate (2) and a top plate (1). The bottom plate (5), the first dielectric substrate (4), the intermediate layer (12), the second dielectric substrate (2) and the top plate (1) are arranged in sequence from bottom to top. The first dielectric substrate (4), the second dielectric substrate (2) and the top plate (1) are correspondingly provided with via hole arrays (6). The bottom plate (5), the first dielectric substrate (4), the second dielectric substrate (2), the via hole arrays (6) and the top plate (1) form two SIW resonators (13). The two SIW resonators (13) are symmetrically distributed left and right. An adjacent side of the two SIW resonators (13) forms a common wall (14). It is characterized in that, The intermediate layer (12) includes at least one strip-line resonator, and the strip-line resonator includes a U-shaped half-wavelength strip-line resonator (3) or a combination of a U-shaped half-wavelength strip-line resonator (3) and a full-wavelength strip resonator (10); The main body of the U-shaped half-wavelength strip-line resonator (3) has a U-shaped structure. Blind holes (7) are provided at both ends of the U-shaped half-wavelength strip-line resonator (3). The blind holes (7) are located on the first dielectric substrate (4) and penetrate through the first dielectric substrate (4). The U-shaped half-wavelength strip-line resonator (3) is arranged at the upper, middle or lower part of the common wall (14), and the midpoint of the U-shaped half-wavelength strip-line resonator (3) is located on the common wall (14); The via array (6) includes a plurality of vias. The vias are circular holes. The plurality of vias are arranged near the edges of the first dielectric substrate (4), the second dielectric substrate (2) and the top plate (1) and the common wall (14). The vias vertically penetrate through the first dielectric substrate (4), the second dielectric substrate (2) and the top plate (1). The via array (6) has a gap at the position of the common wall (14). According to the position of the gap, it is divided into an upper array and a lower array. The upper array is an E-shaped arranged horizontally, and the lower array is an E-shaped mirror image of the E-shaped arranged horizontally with the upper array; 2. The substrate integrated waveguide filter structure based on a hybrid structure according to claim 1, characterized in that, The top plate (1) includes a rectangular plate and two feed lines (8). One feed line (8) is provided on each of the left and right sides of the rectangular plate. The rectangular plate and the two feed lines (8) are an integral structure. Two horizontally arranged L-shaped holes (9) are opened at the connection of the feed line (8) and the top plate (1). The two horizontally arranged L-shaped holes (9) are respectively located on the upper and lower sides of the connection of the feed line (8) and the top plate (1). The vertical section of the upper horizontally arranged L-shaped hole (9) faces upward, and the vertical section of the lower horizontally arranged L-shaped hole (9) faces downward; There is a gap between the vias of the upper array and the vias of the lower array at the position of the top plate (1) corresponding to the L-shaped hole (9).

3. The design method of the substrate integrated waveguide filter structure based on the hybrid structure according to claim 1, characterized in that Including: Step 1: Determine the materials of the first dielectric substrate (4) and the second dielectric substrate (2) based on the relative dielectric constant, loss tangent and cost, and set the operating frequency and order of the filter; Step 2: Set the number of required resonators according to the order of the filter, and calculate the sizes of the SIW resonator (13) and the strip-line resonator according to the operating frequency of the filter; Step 3: Set the equivalent topological structure of the filter and the coupling matrix corresponding to the equivalent topological structure, and determine the coupling coefficient between each resonator, the response of the coupling matrix, and the number and shape of the strip-line resonators according to requirements; Step 4: Establish a simulation model of the hybrid substrate integrated waveguide filter, optimize the simulation model, and make the performance of the filter meet the requirements; Step 5: Verify the theory by comparing the simulation results with the response of the coupling matrix, and complete the construction of the substrate integrated waveguide filter based on the hybrid structure.

4. A directly coupled third-order hybrid SIW filter, characterized in that, Adopt a hybrid - structure substrate - integrated waveguide band - pass filter structure according to claim 1. The stripline resonator includes a U - shaped half - wavelength stripline resonator (3). The U - shaped half - wavelength stripline resonator (3) includes a U - shaped stripline and blind vias (7). Blind vias (7) are connected to both ends of the U - shaped stripline. Each blind via (7) vertically penetrates the first dielectric substrate (4). The two blind vias (7) are symmetrically distributed along the common wall (14). The two SIW resonators (13) and the U - shaped half - wavelength stripline resonator (3) form a main coupling path.

5. A fifth-order hybrid SIW filter based on a box-shaped topology structure, characterized in that, Adopt a hybrid - structure substrate - integrated waveguide band - pass filter structure according to claim 1. The stripline resonator includes a combination of a U - shaped half - wavelength stripline resonator (3) and two full - wavelength stripline resonators (10). The U - shaped half - wavelength stripline resonator (3) includes a U - shaped stripline and blind vias (7). Blind vias (7) are connected to both ends of the U - shaped stripline. Each blind via (7) vertically penetrates the first dielectric substrate (4). The two full - wavelength stripline resonators (10) are respectively arranged in parallel on the upper and lower sides of the U - shaped half - wavelength stripline resonator (3). The mid - points of the two full - wavelength stripline resonators (10) are located on the common wall (14). Each full - wavelength stripline resonator (10) includes a stripline and blind vias (7). One blind via (7) is provided at both ends of the stripline, and the stripline is connected to the blind vias (7). The two SIW resonators (13), the U - shaped half - wavelength stripline resonator (3) and the two full - wavelength stripline resonators (10) form four transmission zeros, three main coupling paths and one cross - coupling path.

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