Miniaturized broadband 90-degree hybrid bridge
By using a 6-layer PCB design and an optimized 90° hybrid bridge, the size and bandwidth issues of bridge products in the P-band were resolved, achieving miniaturization and wide bandwidth, thus meeting the high-performance requirements of modern communication systems.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- GUIYANG XINLUO ELECTRONICS CO LTD
- Filing Date
- 2025-06-13
- Publication Date
- 2026-05-19
AI Technical Summary
Existing bridge products are large in size and have limited bandwidth in the P-band, which cannot meet the requirements for miniaturization and wide bandwidth. In particular, the design of stripline bridges suffers from poor product consistency and cannot meet high power requirements.
It adopts a 6-layer PCB design, including a symmetrically arranged bottom and top layer, an optimized adjustment layer and a stripline coupled signal trace layer. It combines defective ground and curved trace structure, uses specific dielectric materials and metal edging treatment, and optimizes the internal structure of the bridge to achieve miniaturization and wide bandwidth.
It achieves miniaturization (8mm*6mm*0.9mm) and wide bandwidth (225MHz-678MHz, bandwidth of about 3 times the frequency) of the hybrid bridge, with a loss of less than 3.8dB, a phase difference of 90°±5°, an isolation of more than 15dB, and a return loss of more than 15dB, meeting the high performance requirements.
Smart Images
Figure CN224264258U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to a miniaturized, wideband 90° hybrid bridge, belonging to the field of bridge technology. Background Technology
[0002] The 3dB90° hybrid bridge is an important radio frequency device that can distribute and synthesize signals. Internally, it is based on the principle of electromagnetic field coupling and is carefully designed to achieve specific performance. The input signal undergoes complex transformations in the bridge to achieve a 3dB attenuation characteristic and make the output signal phase difference 90°.
[0003] The 3dB90° hybrid bridge has extremely wide applications in modern communication and microwave systems. It can be widely used in 4G / 5G base stations, 5G network coverage, BeiDou navigation, and vehicle-mounted high-precision navigation (autonomous driving) antennas. Notably, it can also perform power combining and distribution, signal acquisition, and other functions in microwave high-power amplifier systems, finding applications in active phased array radar, microwave transceiver components, microwave power amplifiers, radios, and satellite communication products.
[0004] As modern communication and microwave systems develop towards miniaturization and integration, the requirements for the size and performance of bridge circuits are becoming increasingly stringent. Therefore, high-performance, miniaturized bridge circuit design is extremely crucial for component design.
[0005] Currently, the most common P-band bridges on the market are transformer-type bridges and stripline-type bridges. However, the saturation magnetization of the ferrite (commonly known as magnetic rings) used in transformer-type bridges is closely related to temperature and frequency, resulting in poor product consistency, a large workload for production and debugging, and an inability to meet high-power requirements. Common P-band stripline-type bridges, based on transmission line design theory, require a stripline length that meets a quarter wavelength requirement, leading to larger product sizes and narrower bandwidth, typically between 1.1 and 1.5 octaves. Therefore, optimized internal structures and specialized designs are needed to meet the demands for miniaturized and wide-bandwidth stripline bridges. Utility Model Content
[0006] The technical problem to be solved by this utility model is to provide a miniaturized wideband 90° hybrid bridge with smaller product size and increased bandwidth, which meets the requirements of miniaturized and wideband stripline bridge.
[0007] The technical solution adopted by this utility model is as follows: A miniaturized broadband 90° hybrid bridge, comprising a 6-layer PCB board, namely a symmetrically arranged bottom and top layer, a first optimization adjustment layer and a second optimization adjustment layer, and a first stripline coupled signal trace layer and a second stripline coupled signal trace layer. Input terminals, output 0° 3dB terminals, output 90° 3dB terminals, and isolation terminals are arranged at the four corners of the PCB board. Two large-area grounding shields electrically connected to each other are arranged in the middle of both the bottom and top layers. The first and second optimization adjustment layers each have four open-circuit stubs at four ports and two defect grounds on the front and back sides. The trace length of the first and second stripline coupled signal trace layers is 1 / 4 wavelength of the center frequency. The first and second stripline coupled signal trace layers are configured as curved traces. A first Rogers circuit is arranged between the bottom layer and the first optimization adjustment layer. A Rogers Ro4350B substrate is provided between the first optimization adjustment layer and the first stripline coupled signal trace layer, a first Rogers 4450F prepreg is provided between the first stripline coupled signal trace layer and the second stripline coupled signal trace layer, a second Rogers 4450F prepreg is provided between the second stripline coupled signal trace layer and the second optimization adjustment layer, and a second Rogers Ro4350B substrate is provided between the second optimization adjustment layer and the top layer.
[0008] Furthermore, the aforementioned defective grounds are constructed by cascading 15 periodically staggered T-shaped defective grounds, and the cascaded T-shaped defective grounds are connected to the large-area grounding shielding surface via the metal edging.
[0009] Furthermore, the corner cutting treatment at the bends of the aforementioned curved traces, and the rectangular metal grounding plates are all installed near the four ports of the first stripline coupled signal trace layer and the second stripline coupled signal trace layer.
[0010] Furthermore, the PCB board 1 is edged with metal on all four sides, and the four ports are metallized with semi-circular holes.
[0011] Furthermore, the thickness of the Rogers Ro4350B sheet is 0.254 mm, the thickness of the first Rogers 4450F prepreg is 0.1 mm, the thickness of the FR4 prepreg sheet is 0.05 mm, the thickness of the second Rogers 4450F prepreg is 0.1 mm, and the thickness of the second Rogers Ro4350B sheet is 0.254 mm.
[0012] The beneficial effects of this utility model are as follows: Compared with the prior art, this utility model adopts a hybrid bridge with a 6-layer PCB board arrangement, which meets the requirements of miniaturized and wide-bandwidth stripline bridge. After testing, the hybrid bridge has an application frequency of 225MHz-678MHz, a bandwidth of about 3 times the frequency (678 / 225), a size of 8mm*6mm*0.9mm (the existing size is 21mm*19mm*3.6mm), a loss of less than 3.8dB, a phase difference of 90°±5°, an isolation of more than 15dB, and a return loss of more than 15dB. Attached Figure Description
[0013] Figure 1 This is the schematic diagram of a 90° hybrid bridge;
[0014] Figure 2 This is a three-dimensional structural diagram (perspective) of a 90° hybrid bridge.
[0015] Figure 3 This is a front view (perspective) of the 90° hybrid bridge structure.
[0016] Figure 4 This is a left-side structural schematic diagram (perspective) of a 90° hybrid bridge.
[0017] Figure 5 This is a top view of the 90° hybrid bridge structure (excluding the sheet metal between layers 1-6).
[0018] Figure 6 This is a schematic diagram of the three-dimensional structure of a 90° hybrid bridge;
[0019] Figure 7 This is a top view of the 90° hybrid bridge structure;
[0020] Figure 8 yes Figure 7 Schematic diagram of the cross-sectional structure of the middle AA section;
[0021] Figure 9 This is the layout diagram of the bottom layer of the PCB board;
[0022] Figure 10 This is the layout diagram of the first adjustment and optimization layer on the PCB board;
[0023] Figure 11 This is a layout diagram of the first signal layer on the PCB board;
[0024] Figure 12 This is a layout diagram of the second signal layer on the PCB board;
[0025] Figure 13 This is a layout diagram of the second adjustment and optimization layer on the PCB board;
[0026] Figure 14 This is a layout diagram of the top layer of the PCB board;
[0027] Figure 15 This is the circuit diagram of a 90° hybrid bridge;
[0028] Figure 16 It is an S-parameter curve graph;
[0029] Figure 17 It is a phase difference curve. Detailed Implementation
[0030] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.
[0031] Figure 1 This is a schematic diagram of a 90° hybrid bridge. The bridge consists of two striplines coupled through the wide sides of the upper and lower striplines. Pin 1 is the input terminal, and Pin 2 is the isolation terminal. The signal is input through port 1 and output through port 3. Part of the signal is output through port 4 via coupling. The output signals of port 3 and port 4 are 90° out of phase. The product ports are interchangeable.
[0032] The overall structure of the design is as follows: Figure 2 As shown, the product is designed as a multi-layer PCB hybrid integrated design. The main technical parameters of the product are as follows: application frequency 225MHz-678MHz, bandwidth approximately 3 times the frequency (678 / 225), size 8mm*6mm*0.9mm, loss less than 3.8dB, phase difference 90°±5°, isolation greater than 15dB, and return loss greater than 15dB.
[0033] Example 1: As Figure 1-15As shown, a miniaturized broadband 90° hybrid bridge includes a 6-layer PCB board 1, namely, layers 1 and 6 are the bottom layer 9 and top layer 10 respectively, layers 2 and 5 are the first optimization adjustment layer 11 and the second optimization adjustment layer 12 respectively, and layers 3 and 4 are the first stripline coupled signal trace layer 13 and the second stripline coupled signal trace layer 14 respectively. Four port pads are provided at the four corners of the PCB board 1, namely, input terminal 2, output 0° 3dB terminal 3, output 90° 3dB terminal 4, and isolation terminal 5 respectively. Two large-area grounding shields 6, electrically connected to each other, are provided in the middle of both the bottom layer 9 and the top layer 10 to achieve grounding. The large-area grounding shields 6 are cross-shaped. The first optimization adjustment layer 11 and... The second optimization adjustment layer 12 has four open-circuit stubs 7 at four ports and two defect grounds 8 on the front and back sides, for a total of eight open-circuit stubs 7 and four defect grounds 8. The four open-circuit stubs 7 are arranged in pairs facing each other. The defect grounds 8 are cascaded in 15 periodically staggered T-shaped defect grounds. The cascaded T-shaped defect grounds are connected to the large-area grounding shield 6 by the metal edging. The trace length of the first stripline coupled signal trace layer 13 and the second stripline coupled signal trace layer 14 is 1 / 4 wavelength of the center frequency. The first stripline coupled signal trace layer 13 and the second stripline coupled signal trace layer 14 use curved traces. A first Rogers layer with a dielectric constant of 3.66 is set between the bottom layer and the first optimization adjustment layer. Rogers Ro4350B substrate 15, Rogers Ro4350B substrate 15 has a thickness of 0.254mm. A first Rogers 4450F prepreg 16 with a dielectric constant of 3.52 is placed between the first optimization adjustment layer 11 and the first stripline coupled signal routing layer 13. The first Rogers 4450F prepreg 16 has a thickness of 0.1mm. An FR4 prepreg substrate 17 with a dielectric constant of 3.96 is placed between the first stripline coupled signal routing layer 13 and the second stripline coupled signal routing layer 14. The FR4 prepreg substrate 17 has a thickness of 0.05mm. A second Rogers 4450F prepreg 18 with a dielectric constant of 3.52 is placed between the second stripline coupled signal routing layer 14 and the second optimization adjustment layer 12. The second Rogers 4450F prepreg 18 has a thickness of 0.1mm. A second Rogers 4450F prepreg with a dielectric constant of 3.66 is placed between the second optimization adjustment layer 12 and the top layer 10. The Rogers Ro4350B board 19 has a thickness of 0.254mm. The 6-layer PCB is made by laminating and mixing the first Rogers Ro4350B board 15, the first Rogers 4450F prepreg 16, the FR4 prepreg board 17, the second Rogers 4450F prepreg 18, and the second Rogers Ro4350B board 19. The PCB 1 has metal edging on all four sides and semi-circular metallized holes at the four ports.The corners of the curved traces are beveled, and rectangular metal plates 20 are grounded near the four ports of the first stripline coupled signal trace layer 13 and the second stripline coupled signal trace layer 14.
[0034] The first optimization adjustment layer 11 and the second optimization adjustment layer 12 respectively add stubs to the four ports and construct defective grounds on both sides to improve bandwidth and return loss. Adding stubs and open transmission lines increases coupling section capacitance compensation, thereby improving isolation and bandwidth. Constructing defective grounds involves etching periodic or non-periodic shapes on the grounding metal plate to give it band-stop characteristics, slow wave characteristics, and high equivalent characteristic impedance, thus increasing bandwidth. The area occupied is reduced by bending the traces, and the corners of the traces are chamfered to avoid impedance mismatch. Metal edging is used around the perimeter to shield interference and electromagnetic leakage, and the ports are metallized with semi-circular holes to ensure welding reliability.
[0035] Example 2: As Figure 1-14 As shown, a design method for a miniaturized broadband 90° hybrid bridge is presented. The method involves a symmetrical 6-layer PCB design, with layers 1 and 6 being the bottom and top layers, respectively. Four port pads are positioned at the four corners of the hybrid bridge, representing the input, 0° 3dB output, 90° 3dB output, and isolation terminals, respectively. A large grounded shield is located in the center. Layers 2 and 5 are the first and second optimization adjustment layers, respectively, with stubs added to the four ports and defect grounds constructed on both sides. Layer 3... Layer 1 and Layer 2 are respectively the first and second stripline coupled signal trace layers. The trace lengths of the first and second stripline coupled signal trace layers are 1 / 4 wavelength of the center frequency. Both layers use curved traces with chamfered corners. Grounding is added at the ports (rectangular metal sheets and metal edging connected to the large-area grounding) for shielding. A Rogers dielectric material with a dielectric constant of 3.66 is used between Layer 1 and Layer 2. The 6-layer PCB is made of Ro4350B substrate with a dielectric thickness of 0.254mm. The second and third layers are separated by Rogers 4450F prepreg with a dielectric constant of 3.52 and a dielectric thickness of 0.1mm. The third and fourth layers are separated by FR4 prepreg with a dielectric constant of 3.96 and a dielectric thickness of 0.05mm. The fourth and fifth layers are separated by Rogers 4450F prepreg with a dielectric constant of 3.52 and a dielectric thickness of 0.1mm. The fifth and sixth layers are separated by Rogers Ro4350B substrate with a dielectric constant of 3.66 and a dielectric thickness of 0.254mm. The PCB is made by laminating and mixing the layers. The edges are metal-edged and the ports are metallized with semi-circular holes.
[0036] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the protection scope of the claims.
Claims
1. A miniaturized broadband 90° hybrid bridge, characterized in that, The PCB consists of six layers: a symmetrically arranged bottom and top layer, a first optimization adjustment layer, a second optimization adjustment layer, a first stripline coupled signal trace layer, and a second stripline coupled signal trace layer. Input terminals, output 0° 3dB terminals, output 90° 3dB terminals, and isolation terminals are located at the four corners of the PCB. Two large-area grounding shields, electrically connected to each other, are located in the center of both the bottom and top layers. The first and second optimization adjustment layers each have four open-circuit stubs at four ports and two defect grounds on the front and back sides. The trace length of the first and second stripline coupled signal trace layers is 1 / 4 wavelength of the center frequency, and both layers are configured with curved traces. A first Rogers layer is located between the bottom layer and the first optimization adjustment layer. A Rogers Ro4350B substrate is provided between the first optimization adjustment layer and the first stripline coupled signal trace layer, a first Rogers 4450F prepreg is provided between the first stripline coupled signal trace layer and the second stripline coupled signal trace layer, a second Rogers 4450F prepreg is provided between the second stripline coupled signal trace layer and the second optimization adjustment layer, and a second Rogers Ro4350B substrate is provided between the second optimization adjustment layer and the top layer.
2. A miniaturized wideband 90° hybrid according to claim 1, characterized in that The defect ground is constructed by cascading 15 periodically staggered T-shaped defect grounds, and the cascaded T-shaped defect grounds are connected to the large-area grounding shield by the metal edging.
3. The miniaturized broadband 90° hybrid according to claim 1, wherein, The corners of the curved traces are beveled, and rectangular metal plates are grounded near the four ports of the first and second stripline coupled signal trace layers.
4. The miniaturized broadband 90° hybrid according to claim 1, wherein, The PCB board is edged with metal on all four sides, and the four ports are metallized with semi-circular holes.
5. The miniaturized broadband 90° hybrid according to claim 1, wherein, The thickness of the Rogers Ro4350B sheet is 0.254mm, the thickness of the first Rogers Ro4450F prepreg is 0.1mm, the thickness of the FR4 prepreg sheet is 0.05mm, the thickness of the second Rogers Ro4450F prepreg is 0.1mm, and the thickness of the second Rogers Ro4350B sheet is 0.254mm.