A multilayer dual-channel substrate integrated waveguide filter
By designing slots and port positions in multilayer substrate integrated waveguide filters, the problems of large size and low isolation of microwave devices are solved, achieving compact and highly isolated dual-channel filtering functionality.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NANJING UNIV OF POSTS & TELECOMM
- Filing Date
- 2026-04-24
- Publication Date
- 2026-06-05
AI Technical Summary
Existing microwave devices in dual-channel device structures suffer from problems such as large size, high insertion loss, and poor isolation between passband modes, making it difficult to achieve compactness and high isolation with flexible frequency adjustment.
Slots in different directions are set between the SIW cavities of the multilayer substrate integrated waveguide filter, especially cross slots are set on the metal substrate to physically separate the TE102 and TE201 modes, and high isolation is achieved through port position design.
It achieves good frequency selectivity and high channel isolation in a compact size, suppresses mode interference and crosstalk, and improves the performance of the filter.
Smart Images
Figure CN122158904A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of microwave communication technology, and in particular to a multilayer dual-channel substrate integrated waveguide filter. Background Technology
[0002] The rapid iteration of wireless communication and sensing technologies has driven the development of microwave devices towards miniaturization, integration, multi-band operation, and multi-functionality. Traditional multi-band filter designs, such as cascaded filter banks or single-cavity multimode topologies, generally suffer from bottlenecks such as large size, high insertion loss, and poor mode isolation between passbands. In recent years, substrate-integrated waveguides have become the preferred technology for developing high-performance filters due to their low transmission loss, high quality factor, and good compatibility with planar circuits. However, achieving high isolation between dual channels within a compact dual-channel device structure with flexible adjustable operating frequency and bandwidth remains a critical research challenge in the field of radio frequency devices. Summary of the Invention
[0003] The purpose of this invention is to provide a multilayer dual-channel substrate integrated waveguide filter, which uses slots of different directions on the metal substrate between each substrate integrated waveguide (SIW) cavity to enable the filter to exhibit good frequency selectivity and high channel isolation in a compact size.
[0004] To achieve the above objectives, the present invention is implemented using the following technical solution: This invention provides a multilayer dual-channel substrate integrated waveguide filter, comprising a plurality of SIW cavities stacked sequentially, wherein: the second metal substrate of the top SIW cavity is provided with a first directional slot; and the first metal substrate of the bottom SIW cavity is provided with a second directional slot. In the intermediate SIW cavity, except for the top SIW cavity and the bottom SIW cavity: the first metal substrate of the second SIW cavity is provided with a first directional groove, the second metal substrate of the penultimate SIW cavity is provided with a second directional groove, and the remaining metal substrates are provided with a cross groove formed by the combination of the first directional groove and the second directional groove. The intersection of the cross grooves is located at the center of the SIW cavity; the first direction groove and the second direction groove are aligned with the cross groove. The first channel of the filter includes a first input port, all first-direction slots, and a first output port; The second channel of the filter includes a second input port, all second-direction slots, and a second output port.
[0005] Optionally, the SIW cavity includes two metal substrates and a dielectric substrate with an array of metallized vias between the two metal substrates; The metallized vias in the metallized via array form a rectangle with the upper and lower metal substrates, and the radii of the metallized vias are all the same.
[0006] Optionally, the first input port is disposed on the first metal substrate of the top-layer SIW cavity; The second input port is disposed on the first metal substrate of the second layer SIW cavity of the filter; The first output port is disposed on the second metal substrate of the penultimate SIW cavity of the filter; The second output port is located on the second metal substrate of the bottom SIW cavity of the filter.
[0007] By setting the four input and output ports of the two channels on SIW cavities of different layers, high isolation between the two channels is achieved.
[0008] Optionally, the first channel couples the TE102 mode of the SIW cavity and suppresses the TE201 mode of the SIW cavity; The second channel suppresses the TE102 mode of the SIW cavity and couples the TE201 mode of the SIW cavity.
[0009] Optionally, the operating center frequencies of the first and second channels are controlled by the length and width of the SIW cavity.
[0010] Optionally, both the first and second directional slots are parallel to the sidewall of the SIW cavity. By adjusting the length of the first directional slot, the magnetic coupling of the TE102 mode is controlled, and by adjusting the length of the second directional slot, the magnetic coupling of the TE201 mode is controlled. Controlling the magnetic coupling of the TE102 and TE201 modes can control the working bandwidth of the channel.
[0011] Optionally, all input and output ports adopt a transition structure from microstrip line to coplanar waveguide.
[0012] Optionally, the metal substrate of the top SIW cavity is offset in one direction according to the length of the coplanar waveguide transition structure of the second SIW cavity; the metal substrate of the bottom SIW cavity is offset in one direction according to the length of the coplanar waveguide transition structure of the penultimate SIW cavity.
[0013] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: The first directional slot of this invention is located at the strongest magnetic field of the TE102 mode, and the second directional slot is located at the strongest magnetic field of the TE201 mode. This physically separates the TE102 and TE201 modes, connecting the four ports of the two channels to different cavities, thereby improving isolation and suppressing mode interference and crosstalk of traditional multi-channel filters. This allows the filter to exhibit good frequency selectivity and high channel isolation in a compact size. Attached Figure Description
[0014] Figure 1 This is an exploded view of the multilayer dual-channel substrate integrated waveguide filter of the present invention; Figure 2 This is a schematic diagram of the S-parameter test curves of the multilayer dual-channel substrate integrated waveguide filter of the present invention.
[0015] The markings in the diagram are: 1-First metal substrate of the top SIW cavity, 2-First dielectric substrate, 3-Second metal substrate of the top SIW cavity, 4-First metal substrate of the second SIW cavity, 5-Second dielectric substrate, 6-Second metal substrate of the second SIW cavity, 7-First metal substrate of the third SIW cavity, 8-Third dielectric substrate, 9-Second metal substrate of the third SIW cavity, 10-First metal substrate of the bottom SIW cavity, 11-Fourth dielectric substrate, 12-Second metal substrate of the bottom SIW cavity, 13-First directional slot, 14-Second directional slot, 15-First input port, 16-Second input port, 17-First output port, 18-Second output port, 19-Metalized via. Detailed Implementation
[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Example 1:
[0017] This embodiment describes a multilayer dual-channel substrate integrated waveguide filter, such as... Figure 1 As shown, it includes multiple SIW cavities stacked sequentially. Among the multiple SIW cavities: the second metal substrate 3 of the top SIW cavity is provided with a first directional slot 13; the first metal substrate 10 of the bottom SIW cavity is provided with a second directional slot 14. In the intermediate SIW cavity, except for the top SIW cavity and the bottom SIW cavity: the first metal substrate 4 of the second SIW cavity is provided with a first directional slot 13, the second metal substrate 9 of the penultimate SIW cavity is provided with a second directional slot 14, and the remaining metal substrates are provided with a cross slot formed by the combination of the first directional slot 13 and the second directional slot 14. The intersection of the cross grooves is located at the center of the SIW cavity; the first direction groove 13 and the second direction groove 14 are aligned with the cross grooves. The first channel of the filter includes a first input port 15, all first-direction slots 13, and a first output port 17. The second channel of the filter includes a second input port 16, all second-direction slots 14, and a second output port 18.
[0018] In some embodiments, the first input port 15 is disposed on the metal substrate 1 of the top SIW cavity of the filter; The second input port 16 is disposed on the first metal substrate 4 of the second SIW cavity of the filter; The first output port 17 is disposed on the penultimate metal substrate of the filter; The second output port 18 is disposed on the second metal substrate 12 of the bottom SIW cavity of the filter.
[0019] By setting the four input and output ports of the two channels on SIW cavities of different layers, high isolation between the two channels is achieved.
[0020] In some embodiments, the SIW cavity includes two metal substrates and a dielectric substrate with an array of metallized vias between the two metal substrates; The metallized vias 19 in the metallized via array form a rectangle with the upper and lower metal substrates, and the radii of the metallized vias 19 are all the same.
[0021] In some implementations, the first channel couples the TE102 mode of the SIW cavity and suppresses the TE201 mode of the SIW cavity; The second channel suppresses the TE102 mode of the SIW cavity and couples the TE201 mode of the SIW cavity.
[0022] In some implementations, the operating center frequencies of the first and second channels are controlled by the length and width of the SIW cavity.
[0023] In some embodiments, the first directional slot 13 and the second directional slot 14 are both parallel to the sidewall of the SIW cavity. By adjusting the length of the first directional slot, the magnetic coupling of the TE102 mode is controlled, and by adjusting the length of the second directional slot, the magnetic coupling of the TE201 mode is controlled. Controlling the magnetic coupling of the TE102 mode and the TE201 mode can control the working bandwidth of the channel.
[0024] In some implementations, all input and output ports employ a microstrip line to coplanar waveguide transition structure.
[0025] In some embodiments, the metal substrate of the top SIW cavity is offset in one direction according to the length of the coplanar waveguide transition structure of the second SIW cavity; the metal substrate of the bottom SIW cavity is offset in one direction according to the length of the coplanar waveguide transition structure of the penultimate SIW cavity.
[0026] The orthogonal degenerate modes (TE102 and TE201) have magnetic fields that are orthogonal at 90 degrees, but both have high magnetic field strength at the center of the SIW cavity, while the TE101 mode has a weak magnetic field strength at the center. Therefore, adjacent SIW cavities are magnetically coupled through a first-direction slot and a second-direction slot, and both channels can effectively suppress the TE101 mode. The first-direction slot can effectively magnetically couple the TE102 mode to suppress the TE201 mode, and the second-direction slot can effectively magnetically couple the TE201 mode to suppress the TE102 mode. The physical separation of the TE102 and TE201 modes improves isolation. At the same time, combined with the orthogonal characteristics of the TE102 and TE201 modes, the input and output ports of different channels are designed on both sides of the SIW cavity. This design can achieve excellent frequency selectivity and channel isolation. Example 2:
[0027] This embodiment uses a four-layer SIW cavity as an example to introduce a multilayer dual-channel substrate integrated waveguide filter, such as... Figure 1As shown, the top-layer SIW cavity of the filter in the figure is composed of a first metal substrate 1, a first dielectric substrate 2 and an array of metallized vias disposed inside the top-layer SIW cavity, and a second metal substrate 3 of the top-layer SIW cavity; the second-layer SIW cavity is composed of a first metal substrate 4, a second dielectric substrate 5 and an array of metallized vias disposed inside the second-layer SIW cavity, and a second metal substrate 6 of the second-layer SIW cavity; the third-layer SIW cavity is composed of a first metal substrate 7, a third dielectric substrate 8 and an array of metallized vias disposed inside the third-layer SIW cavity, and a second metal substrate 9 of the third-layer SIW cavity; the bottom-layer SIW cavity is similar to the top-layer cavity, and is composed of a first metal substrate 10, a fourth dielectric substrate 11 and an array of metallized vias disposed inside the bottom-layer SIW cavity, and a second metal substrate 12 of the bottom-layer SIW cavity; wherein, the radius of the metallized vias on the dielectric substrate is uniform, which can be 0.4 mm, and the spacing between the centers of the metallized vias can be 1.25 mm.
[0028] The filter adopts a dual-input dual-output architecture. Specifically, the first metal substrate 1 of the top SIW cavity of the filter is provided with a first input port 15, the first metal substrate 4 of the second SIW cavity of the filter is provided with a second input port 16, the second metal substrate 9 of the third SIW cavity of the filter is provided with a first output port 17, and the second metal substrate 12 of the bottom SIW cavity is provided with a second output port 18. Both the input and output ports adopt a transition structure from microstrip line to coplanar waveguide.
[0029] definition Figure 1 The X direction is the first direction, and the Y direction is the second direction. Cross-shaped slots are precisely etched on the second metal substrate 6 of the second-layer SIW cavity and the first metal substrate 7 of the third-layer SIW cavity. These cross-shaped slots are orthogonally formed by first-direction slots 13 and second-direction slots 14. Simultaneously, first-direction slots of the same specifications are etched at corresponding positions on the second metal substrate 3 of the top-layer SIW cavity and the first metal substrate 4 of the second-layer SIW cavity. Second-direction slots of the same specifications are etched at corresponding positions on the second metal substrate 9 of the three-layer SIW cavity and the first metal substrate 10 of the bottom-layer SIW cavity. The first-direction slots 13 and 14 provide magnetic coupling for the TE102 and TE201 modes. Specifically, the magnetic coupling amount of the TE102 mode can be controlled by adjusting the length and width of the first-direction slot 13, and the magnetic coupling amount of the TE201 mode can be controlled by adjusting the length and width of the second-direction slot 14.
[0030] The first input port 15, all first-direction slots, and the first output port 17 constitute the first channel, which couples the TE102 mode and suppresses the TE201 mode. The second input port 16, all second-direction slots, and the second output port 18 constitute the second channel, which suppresses the TE102 mode and couples the TE201 mode. This combination method can separate the TE102 mode and the TE201 mode, allowing for separate magnetic coupling of either the TE102 mode or the TE201 mode, thus achieving dual-channel operation. Furthermore, the four input and output ports of the two channels are located on different layers of the SIW cavity, achieving high isolation between the two channels. The operating frequency of the dual channels can be adjusted by the length and width of the SIW cavity.
[0031] Through precise design, the first channel can be made symmetrical along the Y-axis and its input / output ports can be located on the central symmetry line of the SIW cavity in the Y direction, which can excite the TE102 mode and suppress the TE201 mode. The second channel can be made symmetrical along the X-axis and its input / output ports can be located on the central symmetry line of the SIW cavity in the X direction, which can excite the TE201 mode and suppress the TE102 mode. Combined with the optimization of the length and width of the SIW cavity, the first channel can support the TE102 mode and suppress the TE201 mode, and the second channel can support the TE201 mode and suppress the TE102 mode. Different channels can work simultaneously without interfering with each other.
[0032] A first Y-direction input port 15 with a center frequency of 12 GHz is disposed on the first metal substrate 1 of the top-layer SIW cavity. A second X-direction input port 16 with a center frequency of 10 GHz is disposed on the first metal substrate 4 of the second-layer SIW cavity. A first Y-direction output port 17 is disposed on the second metal substrate 9 of the third-layer SIW cavity, and a second X-direction output port 18 is disposed on the second metal substrate 12 of the bottom-layer SIW cavity. All ports adopt an optimized gradient microstrip line to coplanar waveguide transition structure. The first Y-direction input port 15 and the first Y-direction output port 17 form a first channel, operating in TE102 mode. The second X-direction input port 16 and the second X-direction output port 18 form a second channel, operating in TE201 mode. At the same time, the top-layer SIW cavity moves as a whole in the X direction, and the moving distance is determined by the transition structure of the second input port 16; the bottom-layer SIW cavity moves as a whole in the Y direction, and the moving distance is determined by the transition structure of the first output port 17.
[0033] like Figure 2As shown in the figure, S11 is the return loss of the first output port 15, and S44 is the return loss of the second input port 16; S21 is the insertion loss of the first channel, S34 is the insertion loss of the second channel, S31 is the isolation between the first input port 15 and the second input port 16, S23 is the isolation between the first output port 17 and the second input port 16, S14 is the isolation between the first input port 15 and the second output port 18, and S24 is the isolation between the first output port 17 and the second output port 18.
[0034] The S-parameter test curves of the filter show that the center frequencies of the two channels are stable at 12 GHz for the first channel and 10 GHz for the second channel, respectively. The -3 dB relative bandwidth is precisely controlled at 0.3 GHz (measured values: 0.31 GHz for the first channel and 0.29 GHz for the second channel). The in-band return losses S11 and S44 are both better than -20 (-22.3 dB for the first channel and -23 dB for the second channel). The isolation between the four different ports of the two channels, S31, S23, S14, and S24, are all better than -55 dB. The S-parameter curves of the filter demonstrate that the passband size can be independently controlled without mutual interference, greatly expanding the center frequency range.
[0035] The aforementioned filter has slots in two directions on the metal substrate between adjacent SIW cavities. The slots are located at the center of the SIW cavity and at the point where the magnetic fields of the TE102 and TE201 modes are strongest, physically separating the TE102 and TE201 modes. Furthermore, the isolation is further improved through the design of the port positions. This unique orthogonal mode coupling mechanism, combined with the multi-layer structure, enables the structure to maintain a compact size while exhibiting good frequency selectivity and high channel isolation. It does not have the mode interference and crosstalk of traditional multi-channel filters, and achieves a high-isolation dual-channel filtering function.
[0036] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A multilayer dual-channel substrate integrated waveguide filter, characterized in that, It includes multiple SIW cavities stacked sequentially, wherein: the second metal substrate (3) of the top SIW cavity is provided with a first directional slot (13); the first metal substrate (10) of the bottom SIW cavity is provided with a second directional slot (14). In the intermediate SIW cavity, except for the top SIW cavity and the bottom SIW cavity: the first metal substrate (4) of the second SIW cavity is provided with a first directional slot (13), the second metal substrate (9) of the penultimate SIW cavity is provided with a second directional slot (14), and the other metal substrates are provided with a cross slot formed by the combination of the first directional slot (13) and the second directional slot (14); The intersection of the cross grooves is located at the center of the SIW cavity; the first direction groove (13) and the second direction groove (14) are aligned with the cross grooves. The first channel of the filter includes a first input port (15), all first direction slots (13), and a first output port (17). The second channel of the filter includes a second input port (16), all second-direction slots (14), and a second output port (18).
2. The multilayer dual-channel substrate integrated waveguide filter according to claim 1, characterized in that, The SIW cavity includes two metal substrates and a dielectric substrate with an array of metallized vias between the two metal substrates. The metallized vias (19) in the metallized via array form a rectangle with the upper and lower metal substrates, and the radii of the metallized vias (19) are all the same.
3. The multilayer dual-channel substrate integrated waveguide filter according to claim 1, characterized in that, The first input port (15) is disposed on the first metal substrate (1) of the top-layer SIW cavity; The second input port (16) is disposed on the first metal substrate (4) of the second layer SIW cavity of the filter; The first output port (17) is disposed on the second metal substrate (9) of the penultimate SIW cavity of the filter; The second output port (18) is disposed on the second metal substrate (12) of the bottom SIW cavity of the filter.
4. The multilayer dual-channel substrate integrated waveguide filter according to claim 1, characterized in that, The first channel couples the TE102 mode of the SIW cavity and suppresses the TE201 mode of the SIW cavity; The second channel suppresses the TE102 mode of the SIW cavity and couples the TE201 mode of the SIW cavity.
5. The multilayer dual-channel substrate integrated waveguide filter according to claim 1, characterized in that, The operating center frequencies of the first and second channels are controlled by the length and width of the SIW cavity.
6. The multilayer dual-channel substrate integrated waveguide filter according to claim 1, characterized in that, The first directional slot (13) and the second directional slot (14) are both parallel to the sidewall of the SIW cavity. By adjusting the length of the first directional slot (13), the magnetic coupling of the TE102 mode is controlled. By adjusting the length of the second directional slot (14), the magnetic coupling of the TE201 mode is controlled. Controlling the magnetic coupling of the TE102 mode and the TE201 mode can control the working bandwidth of the channel.
7. The multilayer dual-channel substrate integrated waveguide filter according to claim 2, characterized in that, All input and output ports employ a transition structure from microstrip line to coplanar waveguide.
8. The multilayer dual-channel substrate integrated waveguide filter according to claim 7, characterized in that, The metal substrate of the top SIW cavity is offset in one direction according to the length of the coplanar waveguide transition structure of the second SIW cavity; the metal substrate of the bottom SIW cavity is offset in one direction according to the length of the coplanar waveguide transition structure of the penultimate SIW cavity.