Waveguide microstrip converter
By adopting a multi-layer metal layer and feed layer ring structure in the waveguide microstrip converter, the coupling between the waveguide and the magnetic field probe is enhanced, and the problems of high transmission loss and insufficient bandwidth are solved, and the excellent performance of low loss and easy assembly is achieved.
Patent Information
- Application Number
- CN202422174325.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-05
- Publication Date
- 2025-08-01
- Estimated Expiration
- 2034-09-05
AI Technical Summary
In modern communication systems, existing waveguide microstrip converters have problems such as high transmission loss and return loss, insufficient bandwidth, and complex assembly.
A waveguide microstrip converter including rectangular waveguides and PCB board is designed. Multiple metal layers and multiple feed layer rings are arranged on the PCB board. The microstrip line convex structure and metalized blind or buried holes are connected to enhance the coupling of the waveguide and the magnetic field probe, and the impedance and transmission loss are optimized.
It achieves low transmission loss and return loss, has sufficient bandwidth, is simple to assemble, is easy to process, and has excellent performance.
Smart Images
Figure CN223181370U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a radar communication converter, in particular to a waveguide-microstrip converter. Background Art
[0002] Waveguide antennas have the advantages of compact structure, low loss and good stability, and have been fully applied in the fields of radar, electronic countermeasure, etc. Microstrip transmission lines have the advantages of low profile and easy conformal shaping. With the rapid development of integrated circuits in recent years, microstrip lines also occupy an important position in modern communication systems.
[0003] The combination of waveguide and microstrip maximizes their respective advantages. In modern communication systems, the waveguide-microstrip converter has become an important energy transfer and transition component, and is also an important part of the millimeter-wave communication radar system. It can be seen that the waveguide-microstrip converter is a key component in the modern millimeter-wave communication radar system, and its performance directly affects the performance of the system. Summary of the Utility Model
[0004] The technical problem to be solved by the utility model is to provide a waveguide-microstrip converter, which has the characteristics of low transmission loss and low return loss, and has sufficient frequency band bandwidth, is easy to assemble, is coordinated with the circuit design, and is convenient for processing and manufacturing.
[0005] The technical solution adopted by the utility model to solve the above technical problem is to provide one, which includes: a rectangular waveguide with a waveguide port; a PCB board arranged at the bottom of the rectangular waveguide, the PCB board includes multiple stacked metal layers and a PCB bottom board layer, and clearance areas are opened on each metal layer, and the projections of each clearance area in the vertical direction of the PCB bottom board layer at least partially overlap; and a plurality of feed layer rings arranged on the PCB board, the plurality of feed layer rings are correspondingly arranged in the clearance areas on different metal layers, each feed layer ring includes a first end and a second end that are connected to each other, the first end is a free end, and the second end of at least one feed layer ring extends linearly outward along the outer edge to form a microstrip line convex structure with an impedance and transmission loss adjustment function, and the feed layer rings on adjacent metal layers are connected through connection holes.
[0006] Further, the feed layer rings include a first feed layer ring, a second feed layer ring and a third feed layer ring arranged in sequence from top to bottom, and the second end of the first feed layer ring extends outward and is provided with the above-mentioned microstrip line convex structure.
[0007] Further, the first end of the first feed layer ring is connected to the second end of the second feed layer ring through a first blind hole, and the first end of the third feed layer ring is connected to the first end of the second feed layer ring through a buried hole.
[0008] Furthermore, the first feed layer ring also includes an end open-circuit short-circuit branch node, one end of which is connected to the metal layer corresponding to the second feed layer ring through a through hole, and the other end of which is connected to the second end of the third feed layer ring through a second blind hole.
[0009] Furthermore, ground through holes are provided on the metal layer at the edge of the clearance area, and the ground through holes on each metal layer are of the same size and have corresponding positions.
[0010] Furthermore, the second end of the first feed layer ring extends outward to form a microstrip feed line port, and the microstrip feed line port serves as a signal output port and input port of the converter.
[0011] Furthermore, the distance between the microstrip protrusion structure and the first feed layer ring is 1.2 mm.
[0012] Furthermore, the length of the microstrip protrusion structure is 1 mm.
[0013] Furthermore, the minimum longitudinal distance between the feed layer ring and the edge of the clearance area is 0.5 mm.
[0014] Furthermore, the shape of the feed layer ring can be circular or square.
[0015] Compared to existing technologies, the present invention offers the following advantages: The waveguide-microstrip converter provided by the present invention utilizes multiple feed layer loop structures constructed within a multilayer printed circuit board to enhance coupling between the waveguide and the magnetic field probe. The multiple feed layer loops are located on different layers of the PCB, and the different loop structures are electrically connected using metalized blind or buried vias. The loops can be circular, square, or other polygonal shapes. The waveguide-microstrip converter provided by the present invention exhibits a port reflection coefficient of less than -30 dB and an in-band loss of less than 0.5 dB within the 77 GHz frequency band. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1a This is a schematic diagram of the PCB plus waveguide structure of the utility model;
[0017] Figure 1b This is a schematic diagram of the explosion of the PCB of the utility model;
[0018] Figure 2 This is a schematic diagram of the front structure of the PCB board of the waveguide-microstrip converter of the utility model;
[0019] Figure 3 This is a schematic diagram of the back structure of the PCB board of the waveguide-microstrip converter of the present invention;
[0020] Figure 4Schematic diagram of the feeding layer ring of the waveguide-microstrip converter of the present utility model;
[0021] Figure 5 Schematic diagram of the influence of the radius of the first feeding layer ring of the feeding layer ring of the present utility model on the performance of the waveguide-microstrip converter;
[0022] Figure 6 Schematic diagram of the influence of the radius of the second feeding layer ring of the feeding layer ring of the present utility model on the performance of the waveguide-microstrip converter;
[0023] Figure 7 Schematic diagram of the influence of the radius of the third feeding layer ring of the feeding layer ring of the present utility model on the performance of the waveguide-microstrip converter;
[0024] Figure 8 Schematic diagram of the influence of the position of the microstrip line protrusion structure of the present utility model on the performance of the converter;
[0025] Figure 9 Schematic diagram of the influence of the length of the microstrip line protrusion structure of the present utility model on the performance of the converter;
[0026] Figure 10 Schematic diagram of the influence of the longitudinal position of the feeding layer ring structure of the present utility model in the clearance on the performance of the converter.
[0027] The markings in the figure are:
[0028] 1 rectangular waveguide 2 PCB board 3 feeding layer ring
[0029] 4 via hole to the ground 5 first feeding layer ring 6 second feeding layer ring
[0030] 7 third feeding layer ring 8 microstrip line protrusion structure 9 first blind hole
[0031] 10 buried hole 11 second blind hole 12 through hole Specific embodiments
[0032] The present utility model will be further described below in conjunction with the accompanying drawings and embodiments.
[0033] Please refer to Figure 1a 、 Figure 1b 、 Figures 2 - 4; The waveguide - microstrip converter provided by the present utility model includes a rectangular waveguide 1 with a waveguide port and a PCB board 2; the PCB board 2 is arranged at the bottom of the rectangular waveguide 1, and the PCB board 2 includes multiple stacked metal layers and a PCB bottom board layer. Clearance areas are provided on each metal layer, and the projections of each clearance area in the vertical direction of the PCB bottom board layer at least partially overlap. Multiple feed layer rings 3 are arranged on the PCB board 2, and the multiple feed layer rings 3 are respectively arranged in the clearance areas on different metal layers. Each feed layer ring 3 includes a first end and a second end that are interconnected. The first end is a free end, and the second end of at least one feed layer ring 3 extends linearly outward along the outer edge to form a microstrip line convex structure 8 with the function of adjusting impedance and transmission loss. The feed layer rings on adjacent metal layers are connected through connection holes.
[0034] In the present utility model, feed layer rings 3 are arranged on the multiple metal layers of the PCB board 2 to enhance the coupling between the waveguide and the magnetic field probe through these feed layer rings 3. Each feed layer ring 3 is provided with a first end and a second end, where the first end is a free end, and the second end can extend linearly outward to form a microstrip line convex structure 8. The impedance and transmission loss of the waveguide - microstrip converter can be adjusted through the microstrip line convex structure 8, improving the performance of the entire waveguide - microstrip converter.
[0035] As an embodiment of the present utility model, please refer to Figure 8 , as the distance between the microstrip line convex structure 8 and the feed layer ring 3 increases, the transmission loss of the waveguide - microstrip converter gradually decreases. Figure 8 In [reference], a shows the distance feed_m_offset between the microstrip line convex structure 8 and the feed layer ring 3; Figure 8 In [reference], b, c, and d are the transmission coefficient curve graph, reflection coefficient curve graph, and Smith impedance circle graph respectively. As the distance between the microstrip convex structure 8 and the feed layer ring 3 increases, the impedance of the waveguide - microstrip converter gradually moves away from the center of the Smith chart. Finally, the optimized distance feed_m_offset between the microstrip line convex structure 8 and the feed layer ring 3 is 1.2 mm.
[0036] As an embodiment of the present utility model, please refer to Figure 9 , as the length of the microstrip line convex structure 8 increases, the transmission loss of the waveguide - microstrip converter shows a trend of first decreasing and then increasing, and the resonance of the waveguide - microstrip converter shows a low - offset trend. Figure 9 In [reference], a shows the length feed_m_l of the microstrip line convex structure 8; Figure 9 In [reference], b, c, and d are the transmission coefficient curve graph, reflection coefficient curve graph, and Smith impedance circle graph respectively. As the length of the microstrip convex structure 8 increases, the impedance of the waveguide - microstrip converter shows the effect of series inductance. Finally, the optimized length feed_m_l of the microstrip line convex structure 8 is 1 mm.
[0037] Specifically, the feeding layer ring 3 includes a first feeding layer ring 5, a second feeding layer ring 6, and a third feeding layer ring 7 which are arranged in sequence from top to bottom. The second end of the first feeding layer ring 5 extends outward and is provided with the microstrip line convex structure 8.
[0038] As an embodiment of the present invention, please refer to Figure 5 , the radius r1 of the first feeding layer ring 5 affects the magnitude of transmission loss, the impedance matching of the converter, and the frequency offset. Figure 5 In [reference], a indicates the radius r1 of the first feeding layer ring 5; Figure 5 In [reference], b, c, and d are respectively the transmission coefficient curve graph, the reflection coefficient curve graph, and the Smith impedance circle graph. As the radius r1 of the first feeding layer ring 5 increases, the transmission loss of the converter gradually decreases. The resonant frequency of the waveguide-microstrip converter gradually decreases with the increase of the radius r1 of the first feeding layer ring 5. The increase of the radius r1 of the first feeding layer ring 5 makes the impedance of the waveguide-microstrip converter present the effect of series inductance. Considering the frequency offset, transmission loss, and impedance matching effect comprehensively, the final optimized size of r1 is 0.606 mm.
[0039] As an embodiment of the present invention, please refer to Figure 6 , the radius r2 of the second feeding layer ring 6 mainly affects the transmission loss and the frequency offset. Figure 6 In [reference], a indicates the radius r2 of the second feeding layer ring 6; Figure 6 In [reference], b, c, and d are respectively the transmission coefficient curve graph, the reflection coefficient curve graph, and the Smith impedance circle graph. As the radius r2 of the second feeding layer ring 6 increases, the transmission loss of the waveguide-microstrip converter shows an increasing trend, and the resonant frequency point of the converter shows a high-offset trend. As the radius r2 of the second feeding layer ring 6 increases, the impedance of the converter presents the effect of series capacitance, but the change amplitude is small. The final optimized radius r2 of the second feeding layer ring 6 is 0.35 mm.
[0040] As an embodiment of the present invention, please refer to Figure 7 , the radius r3 of the third feeding layer ring 7 affects the transmission loss, the frequency offset, and the impedance matching. Figure 7 In [reference], a indicates the radius r3 of the third feeding layer ring 7; Figure 7 In [reference], b, c, and d are respectively the transmission coefficient curve graph, the reflection coefficient curve graph, and the Smith impedance circle graph. As the radius r3 of the third feeding layer ring 7 increases, the transmission loss of the waveguide-microstrip converter gradually decreases, and the resonant frequency point shows a low-offset trend. As the radius r3 of the third feeding layer ring 7 increases, the impedance of the converter presents the effect of series inductance. The final optimized size of the radius r3 of the third feeding layer ring 7 is 0.41 mm.
[0041] As an embodiment of the present invention, please refer to Figure 10, as the longitudinal position of the feeding layer loop 3 in the clearance area increases, the transmission loss of the waveguide-microstrip converter shows a gradually decreasing trend, and the resonance of the converter shows a high-offset trend. Figure 10 In a, it shows the longitudinal position of the feeding layer loop 3 in the clearance area, with a distance feed_offset from the edge of the clearance area; Figure 10 In b, c, and d are the transmission coefficient curve, reflection coefficient curve, and Smith impedance circle diagram respectively. As the longitudinal position of the feeding layer loop structure in the clearance increases, the impedance of the converter shows the effect of series capacitance. Finally, the longitudinal position of the optimized feeding layer loop structure in the clearance area, with a distance feed_offset from the edge of the clearance area, is 0.5 mm.
[0042] As an embodiment of the present invention, the first end of the first feeding layer loop 5 is connected to the second end of the second feeding layer loop 6 through the first blind hole 9, and the first end of the third feeding layer loop 7 is connected to the first end of the second feeding layer loop 6 through the buried hole 10. The multi-layer feeding layer loop 3 is electrically connected through the metallized blind hole or buried hole.
[0043] As an embodiment of the present invention, the first feeding layer loop 5 further includes an open / short-ended stub at the end. One end of the open / short-ended stub is connected to the corresponding metal layer of the second feeding layer loop 6 through the through hole 12, and the other end of the open / short-ended stub is connected to the second end of the third feeding layer loop 7 through the second blind hole 11.
[0044] As an embodiment of the present invention, the lower vias 4 are opened on the metal layer at the edge of the clearance area, and the lower vias 4 on each metal layer are of the same size and in corresponding positions. The multi-layer metal layers are connected through the lower vias.
[0045] Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications and improvements without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be defined by the claims.
Claims
1. A waveguide-microstrip converter, characterized in that It includes: A rectangular waveguide with a waveguide opening; A PCB board disposed at the bottom of the rectangular waveguide. The PCB board includes multiple stacked metal layers and a PCB bottom board layer. Clearance areas are formed on each metal layer, and the projections of each clearance area in the vertical direction of the PCB bottom board layer at least partially overlap; And Multiple feed layer rings disposed on the PCB board. The multiple feed layer rings are respectively disposed in the clearance areas on different metal layers. Each feed layer ring includes a first end and a second end that are interconnected. The first end is a free end. The second end of at least one feed layer ring extends linearly outward along the outer edge to form a microstrip line convex structure having an impedance and transmission loss adjustment function. The feed layer rings on adjacent metal layers are connected through connection holes.
2. The waveguide-microstrip converter according to claim 1, characterized in that, The feed layer rings include a first feed layer ring, a second feed layer ring, and a third feed layer ring that are sequentially disposed from top to bottom. The second end of the first feed layer ring extends outward and is provided with the microstrip line convex structure.
3. The waveguide-microstrip converter according to claim 2, wherein The first end of the first feed layer ring is connected to the second end of the second feed layer ring through a first blind hole, and the first end of the third feed layer ring is connected to the first end of the second feed layer ring through a buried hole.
4. The waveguide-microstrip converter according to claim 2, characterized in that, The first feed layer ring further includes an end open / short stub. One end of the end open / short stub is connected to the metal layer corresponding to the second feed layer ring through a through hole, and the other end of the end open / short stub is connected to the second end of the third feed layer ring through a second blind hole.
5. The waveguide-microstrip converter according to claim 2, characterized in that, Via holes to the ground are formed on the metal layer at the edge of the clearance area, and the via holes to the ground on each metal layer are of the same size and corresponding in position.
6. The waveguide-microstrip converter according to claim 2, wherein The second end of the first feed layer ring extends outward to form a microstrip feed port, and the microstrip feed port serves as the signal output port and input port of the converter.
7. The waveguide-microstrip converter according to claim 2, wherein The minimum distance between the microstrip line convex structure and the first feed layer ring is 1.2 mm.
8. The waveguide-microstrip converter according to claim 1, wherein The length of the microstrip line convex structure is 1 mm.
9. The waveguide-microstrip converter according to claim 1, characterized in that, The minimum longitudinal distance between the feed layer ring and the edge of the clearance area is 0.5 mm.
10. The waveguide-microstrip converter according to claim 1, characterized in that The shape of the feed layer ring can be circular or square.