E-band microstrip-to-waveguide switching structure transited by substrate integrated waveguide
By introducing a multi-layer PCB board and a ridge waveguide transition structure into the microstrip-to-waveguide structure and combining it with a substrate-integrated waveguide, a wide-band, low-loss conversion between microstrip lines and rectangular waveguides is achieved, solving the problems of high loss and difficulty in integration in existing technologies. This technology is suitable for millimeter-wave communications and radar systems.
Patent Information
- Application Number
- CN202422549510.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-22
- Publication Date
- 2025-09-09
- Estimated Expiration
- 2034-10-22
AI Technical Summary
The existing microstrip-to-waveguide structure has problems such as high loss, difficulty in integration, high parameter sensitivity and large size in the millimeter wave frequency band, making it difficult to meet the requirements of wide bandwidth, low loss and easy integration.
By adopting a multi-layer PCB board and a ridge waveguide transition structure with uniform thickness, combined with a substrate integrated waveguide and a rectangular waveguide, the TEM mode of the microstrip line is converted into the quasi-TE10 mode of the substrate integrated waveguide through a gradient structure, and then converted into the TE10 mode of the rectangular waveguide, thereby realizing the connection between the horizontal microstrip line and the vertical rectangular waveguide.
A switching structure with wide bandwidth, low loss and easy integration is realized, which is suitable for millimeter wave communication and radar systems and reduces the risk of electromagnetic interference.
Smart Images
Figure CN223321465U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of microwave technology, in particular to the field of SIW technology, and specifically refers to an E-band microstrip to waveguide transition structure transitioned from a substrate integrated waveguide. Background Art
[0002] Waveguides and microstrip are the most widely used transmission lines. Compared to metal waveguides, microstrip lines offer smaller size, lighter weight, wider bandwidth, higher reliability, and lower manufacturing costs. However, they also offer higher losses and lower power handling. Waveguides offer advantages such as low conductor loss, high power handling, no radiation loss, and a simple structure. They are widely used in millimeter-wave communications, radar, remote sensing, and other systems. However, their large size, weight, and inability to integrate have limited their development.
[0003] In the millimeter-wave frequency band, to facilitate testing, antenna feeds, and connections between independent microstrip circuits, it is often necessary to transition the input and output ports of microstrip circuits to rectangular waveguides through a conversion structure. Currently, common transition methods include stepped ridge waveguide transition, ridge fin transition, and coupled probe transition. The ridge fin and coupled probe transition methods are large and inconvenient for PCB integration. While conventional microstrip-to-ridge waveguide structures can be integrated with PCBs, they are highly sensitive to parameters, resulting in misalignment during soldering and poor consistency.
[0004] Patent CN 112736393 A proposes a microstrip-to-waveguide structure based on a multi-layer PCB board, including a multi-layer PCB board and a sealed box waveguide cavity. The structure is relatively bulky and inconvenient to integrate with the PCB board.
[0005] Patent CN 11403881A proposes a microstrip-to-waveguide structure based on coupled feeding, including a substrate and a radiating patch on the substrate. To improve performance, a rectangular cavity is attached to the substrate. This structure is relatively complex, has a narrow bandwidth, and has high loss.
[0006] Patent CN 217334372 U proposes a 77GHz broadband millimeter-wave microstrip-to-waveguide connection structure. By connecting the microstrip feed structure and the patch antenna in a trapezoidal configuration, it achieves transmission impedance matching performance of S11 < -10dB in the 70-82.5GHz range. This structure is easy to process and integrate, but suffers from high losses and the presence of backward radiation during antenna feed, making it susceptible to electromagnetic interference.
[0007] Therefore, how to design a wide-bandwidth, low-loss, easy-to-process, and easy-to-integrate structure is the key to microstrip-to-waveguide technology. Utility Model Content
[0008] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide an E-band microstrip to waveguide transition structure that has a relatively wide bandwidth, relatively low loss, is easy to process and easy to integrate, and has a substrate integrated waveguide transition.
[0009] In order to achieve the above-mentioned purpose, the E-band microstrip to waveguide transition structure of the present invention, which is transitioned from substrate integrated waveguide, has the following structure:
[0010] The invention comprises a multi-layer PCB board 1 and a ridge waveguide transition structure 2 with uniform thickness placed on the multi-layer PCB board 1. The multi-layer PCB board 1 is provided with a microstrip line 11, a substrate integrated waveguide structure 12 and a grounding structure 13 of the ridge waveguide transition structure 2. The multi-layer PCB board 1 also includes a metallized through-hole 14 arranged under the ridge waveguide transition structure 2. The ridge waveguide transition structure 2 adopts a stepped structure to convert the quasi-TE10 mode in the substrate integrated waveguide structure 12 into the TE10 mode in the rectangular waveguide 22. The ridge waveguide transition structure 2 and the metallized through-hole 14 are used to connect the electromagnetic waves between the horizontal microstrip line 11 and the rectangular waveguide 22 with the vertically placed WR12.
[0011] In the E-band microstrip to waveguide transition structure using substrate integrated waveguide as the transition material, the uppermost dielectric material of the multilayer PCB board 1 is Rogers 3003G2, with a dielectric constant of 3.06 and a loss tangent of 0.003.
[0012] In the E-band microstrip to waveguide transition structure transitioned from substrate integrated waveguide, the microstrip line 11 and the substrate integrated waveguide structure 12 are connected via a gradually changing isosceles trapezoidal structure 15 .
[0013] In the E-band microstrip to waveguide transition structure transitioned from substrate integrated waveguide, a width gradient structure 16 exists at the transition between the substrate integrated waveguide structure 12 and the grounding structure 13 of the ridge waveguide transition structure 2 .
[0014] In the E-band microstrip to waveguide transition structure using substrate integrated waveguide as the transition structure, a polygonal groove is formed on the upper surface copper sheet of the substrate integrated waveguide structure 12 near the ridge waveguide transition structure 2 .
[0015] In the E-band microstrip to waveguide transition structure transitioned by substrate integrated waveguide, the ridge waveguide transition structure 2 has a trapezoidal step 21 near the substrate integrated waveguide structure 12, and the trapezoidal step 21 is connected to a height-gradient rectangular waveguide 22.
[0016] In the E-band microstrip to waveguide transition structure transitioned by substrate integrated waveguide, a positioning hole 23 is provided at the tail of the ridge waveguide transition structure 2, and the thickness of the ridge waveguide transition structure 2 is uniform.
[0017] In the E-band microstrip to waveguide transition structure transitioned by substrate integrated waveguide, a cut corner 24 is present at the tail of the ridge waveguide transition structure 2 for converting the horizontally transmitted TE10 mode into the vertically transmitted TE10 mode.
[0018] In the E-band microstrip to waveguide transition structure transitioning from substrate integrated waveguide, the metallized through hole 14 is provided with grounding holes 17 around the through hole.
[0019] In the E-band microstrip to waveguide transition structure using substrate integrated waveguide as the transition structure, the ridge waveguide transition structure 2 is made of aluminum alloy or magnesium alloy.
[0020] This utility model adopts an E-band microstrip-to-waveguide transition structure using a substrate-integrated waveguide. Based on the technical solution of the microstrip-to-ridge waveguide structure, a substrate-integrated waveguide structure is added before the ridge waveguide. The microstrip-to-substrate integrated waveguide structure first converts the TEM mode on the microstrip line into a quasi-TE10 mode within the substrate-integrated waveguide. Then, a stepped structure with a gradient-height ridge waveguide transition structure converts the quasi-TE10 mode into a TE10 mode within the rectangular waveguide, achieving interconnection between the horizontal microstrip line and the vertical rectangular waveguide. This E-band microstrip-to-waveguide transition structure has the advantages of wide bandwidth, low loss, and easy integration. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 This is a schematic diagram of the front structure of the microstrip-to-waveguide transition structure of the present invention;
[0022] Figure 2 This is a schematic diagram of the top surface structure of the microstrip-to-waveguide transition structure of the present invention;
[0023] Figure 3 This is a schematic diagram of the top surface structure of the PCB board in the microstrip-to-waveguide transition structure of the present invention;
[0024] Figure 4 It is a structural schematic diagram of a ridge waveguide transition structure in a microstrip-to-waveguide transition structure of the present invention;
[0025] Figure 5 Schematic diagram of return loss curve of the microstrip-to-waveguide transition structure of the present invention;
[0026] Figure 6 Schematic diagram of the transmission loss curve of the microstrip-to-waveguide transition structure of the present invention;
[0027] Figure 7 This is a schematic diagram of the microstrip-to-waveguide model of the present invention.
[0028] Reference numerals:
[0029] Multilayer PCB board 1, microstrip line 11, substrate integrated waveguide structure 12, ground structure 13, metallized through hole 14, isosceles trapezoidal structure 15, width gradient structure 16, ground hole 17, ridge waveguide transition structure 2, trapezoidal step 21, rectangular waveguide 22, positioning hole 23, cut corner 24 DETAILED DESCRIPTION
[0030] In order to more clearly understand the technical content of the present invention, the following embodiments are given to explain in detail.
[0031] See also Figure 1 , which is a schematic diagram of the front structure of the microstrip-to-waveguide transition structure of the present invention.
[0032] In one embodiment, Figures 1 to 4 As shown, the E-band microstrip to waveguide transition structure transitioned by the substrate integrated waveguide includes a multi-layer PCB board 1 and a ridge waveguide transition structure 2 with uniform thickness placed on the multi-layer PCB board 1. The multi-layer PCB board 1 is provided with a microstrip line 11, a substrate integrated waveguide structure 12 and a grounding structure 13 of the ridge waveguide transition structure 2. The multi-layer PCB board 1 also includes a metallized through-hole 14 arranged under the ridge waveguide transition structure 2; the ridge waveguide transition structure 2 adopts a stepped structure to convert the quasi-TE10 mode in the substrate integrated waveguide structure 12 into the TE10 mode in the rectangular waveguide 22, and utilizes the ridge waveguide transition structure 2 and the metallized through-hole 14 to interconnect the electromagnetic wave between the horizontal microstrip line 11 and the vertically placed rectangular waveguide 22 of WR12.
[0033] The top dielectric material of the multilayer PCB 1 is Rogers 3003G2, with a dielectric constant of 3.06 and a loss tangent of 0.003. The copper thickness of the microstrip line 11 and the substrate integrated waveguide structure 12 is 18 μm.
[0034] In a preferred embodiment, the microstrip line 11 is connected to the substrate integrated waveguide structure 12 via a tapered isosceles trapezoidal structure 15. The width of the isosceles trapezoidal structure 15 at one end connected to the microstrip line 11 is 0.3 mm, and the width of the end connected to the substrate integrated waveguide structure 12 is 0.6 mm. The length of the trapezoidal structure is 0.9 mm.
[0035] In a preferred embodiment, a gradually varying width structure 16 is present at the transition between the substrate integrated waveguide structure 12 and the ground structure 13 of the ridge waveguide transition structure 2. The substrate integrated waveguide structure 12 has a width of 2 mm, a via diameter of 0.25 mm, and a via spacing of 0.5 mm. The ground holes of the ground structure 13 of the ridge waveguide transition structure 2 have a width of 3.5 mm, a via diameter of 0.25 mm, and a via spacing of 0.5 mm. The gradually varying width structure 16 includes a set of gradually varying ground holes, each with a width of 2.75 mm.
[0036] In a preferred embodiment, a polygonal groove is formed on the copper sheet on the upper surface of the substrate-integrated waveguide structure 12 near the ridge waveguide transition structure 2. The polygonal groove is composed of a rectangle with a length of 1.5 mm and a width of 1 mm, a trapezoid with a top base width of 1.5 mm, a bottom width of 3 mm, and a height of 0.68 mm, and a rectangle with a length of 3 mm and a width of 0.89 mm. A grounding hole is provided at the bottom edge of the polygonal groove.
[0037] In a preferred embodiment, the ridge waveguide transition structure 2 has a trapezoidal step 21 near the substrate-integrated waveguide structure 12. This step 21 is followed by a rectangular waveguide 22 with a gradient height, and the gradient structure has a length of 2.5 mm. The thickness of the step 21 is 0.12 mm, and the trapezoidal shape is the same as the trapezoidal shape of the gradient width structure 16 at the transition between the substrate-integrated waveguide structure 12 and the ground structure 13 of the ridge waveguide transition structure 2.
[0038] In a preferred embodiment, a positioning hole 23 is provided at the tail of the ridge waveguide transition structure 2 , and the positioning hole is circular with a diameter of 1 mm. The thickness of the ridge waveguide transition structure 2 is uniform.
[0039] In a preferred embodiment, the tail of the ridge waveguide transition structure 2 has a cut corner 24 with a length of 1.15 mm, which is used to convert the horizontal transmission TE10 mode into the vertical transmission TE10 mode.
[0040] In a preferred embodiment, the metallized through hole 14 has a length of 3 mm, a width of 1.5 mm, a corner radius of 0.5 mm, and grounding holes 17 are provided around the metallized through hole 14 .
[0041] In a preferred embodiment, the ridge waveguide transition structure 2 is made of aluminum alloy or magnesium alloy. The ridge waveguide has an inner diameter of 3 mm, an inner height of 1.5 mm, and a thickness of 0.5 mm.
[0042] In practical applications, the schematic diagram of the E-band microstrip to waveguide model of the substrate integrated waveguide transition of the present invention is as follows Figure 7As shown. For this switching structure, simulation tests on antenna return loss and transmission loss are carried out, as shown in Figure 5 、 Figure 6 As shown, this microstrip-to-waveguide structure exhibits an S11 <-15dB within the 60GHz to 87.5GHz frequency range, a bandwidth of 27.5GHz, and a transmission loss S12 <0.7dB within this frequency band. Compared to existing technologies, the E-band microstrip-to-waveguide transition structure of the present invention, which utilizes a substrate-integrated waveguide as a transition, offers advantages such as wide bandwidth, low loss, and ease of integration. Furthermore, this transition structure can be used not only to test microstrip structures using waveguide interfaces but also to feed microstrip lines to waveguide structures.
[0043] This utility model adopts an E-band microstrip-to-waveguide transition structure using a substrate-integrated waveguide. Based on the technical solution of the microstrip-to-ridge waveguide structure, a substrate-integrated waveguide structure is added before the ridge waveguide. The microstrip-to-substrate integrated waveguide structure first converts the TEM mode on the microstrip line into a quasi-TE10 mode within the substrate-integrated waveguide. Then, a stepped structure with a gradient-height ridge waveguide transition structure converts the quasi-TE10 mode into a TE10 mode within the rectangular waveguide, achieving interconnection between the horizontal microstrip line and the vertical rectangular waveguide. This E-band microstrip-to-waveguide transition structure has the advantages of wide bandwidth, low loss, and easy integration.
[0044] In this specification, the present invention has been described with reference to specific embodiments thereof. However, it will be apparent that various modifications and variations may be made without departing from the spirit and scope of the present invention. Accordingly, the specification and drawings are to be regarded as illustrative rather than restrictive.
Claims
1. A transition structure from substrate integrated waveguide to E-band microstrip waveguide, characterized by: The invention comprises a multi-layer PCB (1) and a ridge waveguide transition structure (2) with uniform thickness placed on the multi-layer PCB (1); a microstrip line (11), a substrate integrated waveguide structure (12) and a grounding structure (13) of the ridge waveguide transition structure (2) are provided on the multi-layer PCB (1); the multi-layer PCB (1) further comprises a metallized through hole (14) provided below the ridge waveguide transition structure (2); the ridge waveguide transition structure (2) adopts a step-by-step structure, and the ridge waveguide transition structure (2) and the metallized through hole (14) are used to interconnect the horizontal microstrip line (11) and the vertical rectangular waveguide (22).
2. The E-band microstrip to waveguide transition structure according to claim 1, characterized in that: The uppermost dielectric material of the multilayer PCB (1) is Rogers 3003G2, with a dielectric constant of 3.06 and a loss tangent of 0.
003.
3. The E-band microstrip to waveguide transition structure according to claim 1, characterized in that: The microstrip line (11) is connected to the substrate integrated waveguide structure (12) via a gradually changing isosceles trapezoidal structure (15).
4. The E-band microstrip to waveguide transition structure according to claim 1, characterized in that: A width gradient structure (16) exists at the transition point between the substrate integrated waveguide structure (12) and the grounding structure (13) of the ridge waveguide transition structure (2).
5. The E-band microstrip to waveguide transition structure according to claim 1, characterized in that: The copper sheet on the upper surface of the substrate integrated waveguide structure (12) is provided with a polygonal groove near the ridge waveguide transition structure (2).
6. The E-band microstrip to waveguide transition structure according to claim 1, characterized in that: The ridge waveguide transition structure (2) has a trapezoidal step (21) near the substrate integrated waveguide structure (12), and the trapezoidal step (21) is followed by a rectangular waveguide (22) with a gradually changing height.
7. The E-band microstrip to waveguide transition structure according to claim 1, characterized in that: A positioning hole (23) is present at the tail of the ridge waveguide transition structure (2), and the thickness of the ridge waveguide transition structure (2) is uniform.
8. The E-band microstrip to waveguide transition structure according to claim 1, characterized in that: The tail of the ridge waveguide transition structure (2) has a cut corner (24) for converting the TE10 mode transmitted horizontally in the substrate integrated waveguide structure (12) into the TE10 mode transmitted vertically in the rectangular waveguide (22).
9. The E-band microstrip to waveguide transition structure according to claim 1, characterized in that: The metallized through hole (14) is provided with grounding holes (17) around the through hole.
10. The E-band microstrip to waveguide transition structure according to claim 1, characterized in that: The ridge waveguide transition structure (2) is made of aluminum alloy or magnesium alloy.