High-power 0-pi phase shifter formed by multiple layers of circuit boards
The high-power 0-π phase shifter, constructed from a multi-layer circuit board, employs a Rogers RO4350 dielectric substrate and a microstrip line structure optimized with cutout areas. It achieves high power tolerance, low loss, and precise phase shifting, solving the problems of phase instability and insufficient power capacity in existing technologies. It also features bandpass filtering and simplifies system integration.
Patent Information
- Application Number
- CN202511758170.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-27
- Publication Date
- 2026-02-10
AI Technical Summary
Existing multilayer board phase shifter designs are insufficient in terms of precise control of phase response, power capacity, heat dissipation and integration, making it difficult to meet the needs of modern high-power applications.
The high-power 0-π phase shifter, constructed from a multi-layer circuit board, is designed with a symmetrical structure. It uses a Rogers RO4350 dielectric substrate and a microstrip line structure optimized with cutout areas, combined with a stepped coupling structure with adjustable width, to achieve precise phase shifting and bandpass filtering functions, and features high power tolerance and low loss.
It realizes a phase shifter with high power capacity, low loss, low cost, and easy integration, with precise phase shift control and stability, and has bandpass filtering function, which reduces insertion loss and improves signal transmission quality and system integration.
Smart Images
Figure CN121507344A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of radio frequency technology, and specifically relates to a high-power 0-π phase shifter composed of a multilayer circuit board. Background Technology
[0002] Phase shifters are key fundamental components in radio frequency and microwave systems, widely used in phased array antennas, beamforming networks, communication systems, and radar. Their performance, such as insertion loss, phase accuracy, power capacity, size, and integration level, directly impacts the overall system performance, cost, and output capability. Traditional phase shifter implementations, such as switched-line and loaded-line phase shifters, while technically mature, often suffer from large size, high insertion loss, and difficulty in precisely controlling phase error. Furthermore, the power capacity of these traditional planar structures is typically limited by conductor losses and heat dissipation, making it difficult to meet the high performance and high reliability requirements of modern high-power applications. To overcome these shortcomings, the industry has begun to adopt multilayer circuit board technology for phase shifter design.
[0003] Multilayer board structures can utilize vertical space to achieve phase shifting through interlayer coupling, helping to reduce planar dimensions and facilitate integration. However, existing multilayer board phase shifter designs still face many challenges. First, the electromagnetic coupling interactions between layers are complex and difficult to control precisely, resulting in poor stability and consistency of the phase response, especially when specific phase shift amounts are required, making it difficult to guarantee accuracy. Second, many designs sacrifice power capacity in pursuit of miniaturization; their thin dielectric and dense coupling structure easily lead to poor heat dissipation and electric field concentration, thus limiting their application at high power. In addition, existing multilayer board phase shifters are functionally limited, typically only implementing phase shifting, lacking additional functions such as filtering and high power tolerance, making it difficult to meet the stringent requirements of diverse circuit functions and high power output in system-level integration. For example, some designs using stripline or wide-side coupling structures have their critical coupling regions encased in a thin dielectric, resulting in highly concentrated electric fields, significantly reducing power capacity, and causing phase drift due to dielectric heating at high power. Meanwhile, the dielectric layer that plays a decisive role in the coupling strength in these structures is often too thin, and its thickness tolerance will greatly amplify the error in phase shift, making it difficult to guarantee consistency during mass production.
[0004] In summary, there is an urgent need in this field for a novel multilayer plate phase shifter solution that can achieve precise and stable control of phase shift while ensuring low loss, weak dispersion and simple structure. It also has comprehensive advantages such as high power capacity, miniaturization, low cost, easy integration and even functional fusion, in order to solve the prominent problems existing in the prior art. Summary of the Invention
[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a high-power 0-π phase shifter composed of a multilayer circuit board.
[0006] The technical problem addressed by this invention is solved as follows:
[0007] A high-power 0-π phase shifter composed of a multilayer circuit board has an overall rectangular laminate structure and is a left-right symmetrical structure. From top to bottom, it consists of a first metal layer, a first dielectric substrate, a second metal layer, a second dielectric substrate, and a third metal layer that are tightly bonded together.
[0008] The structure of the first metal layer includes a bent microstrip line and two high- and low-impedance microstrip lines. The bent microstrip line extends from the upper left edge to the upper right edge of the upper surface of the first dielectric substrate, and is parallel to the long side of the first dielectric substrate, with two gate-shaped protrusions in the middle. The first high- and low-impedance microstrip line is parallel to the long side of the first dielectric substrate, and extends from the lower left edge to the right of the upper surface of the first dielectric substrate. From left to right, it consists of a first low-order microstrip line and a first high-order microstrip line connected in sequence. The second high- and low-impedance microstrip line is parallel to the long side of the first dielectric substrate, and extends from the lower right edge to the left of the upper surface of the first dielectric substrate. From right to left, it consists of a second low-order microstrip line and a second high-order microstrip line connected in sequence. The first high- and low-impedance microstrip line and the second high- and low-impedance microstrip line are collinear but not connected to each other.
[0009] The second metal layer has two cutout regions etched on the basis of fully covering the lower surface of the first dielectric substrate; the first cutout region is located below the first high-order microstrip line, and the second cutout region is located below the second high-order microstrip line; the length of the cutout region is the same as that of the high-order microstrip line, and the width is greater than that of the high-order microstrip line.
[0010] The third metal layer is a coupling structure located below the two hollow areas; the coupling structure is a stepped microstrip line with adjustable width, and its length extends from the left edge of the first hollow area to the right edge of the second hollow area;
[0011] Furthermore, the first port is located on the upper left edge of the cuboid laminated structure and is connected to the left edge of the bent microstrip line; the second port is located on the upper right edge of the cuboid laminated structure and is connected to the right edge of the bent microstrip line; the third port is located on the lower left edge of the cuboid laminated structure and is connected to the left edge of the first low-order microstrip line; the fourth port is located on the lower right edge of the cuboid laminated structure and is connected to the right edge of the second low-order microstrip line; the first and third ports serve as input terminals, and a 180° relative phase shift can be generated between the second and fourth ports.
[0012] Furthermore, the width of the hollowed-out area is six times the width of the high-order microstrip line.
[0013] Furthermore, the dielectric material selected for the first and second dielectric substrates is Rogers RO4350, with a relative permittivity of 3.66, a loss tangent of 0.004, and a thickness of 0.56 mm.
[0014] The beneficial effects of this invention are:
[0015] The phase shifter circuit described in this invention is formed by laminating multiple circuit boards, which effectively overcomes the shortcomings of traditional phase shifter circuits, such as excessive size, high cost, and limited power capacity. It has the advantages of high power tolerance, low loss, weak dispersion, simple structure, low cost, and easy integration with other RF circuits.
[0016] This invention employs a symmetrical balanced structure, which facilitates uniform power distribution between the two paths and avoids local overload. The complete second metal layer (ground layer) forms an effective heat conduction and dissipation path, rapidly dissipating the heat generated in the coupling area. Simultaneously, the use of high-frequency, low-loss, and thermally stable dielectric materials such as Rogers RO4350, combined with optimized-width microstrip lines, ensures stable operation of the circuit under high power, significantly improving power capacity. Precisely etched cutout areas on the second metal layer strictly limit the electromagnetic interaction between the upper high- and low-impedance microstrip lines and the lower coupling structure to a predetermined area, achieving precise control of coupling strength. The cutout area width, larger than that of the high-order microstrip line, effectively reduces phase fluctuations caused by processing tolerances. Furthermore, the adjustable-width stepped coupling structure on the third metal layer provides a convenient means for fine-tuning the phase shift, ensuring phase accuracy and consistency in mass production. The combination of bent microstrip lines and high / low impedance microstrip lines, along with the strong controllable coupling achieved through the cutout area, together create a good bandpass filter frequency response. This structure not only achieves phase shifting but also naturally filters out out-of-band clutter, reduces insertion loss, and exhibits flat group delay characteristics, i.e., weak dispersion, ensuring signal transmission quality. The entire device uses standard multilayer board (PCB) technology, compressing the complex three-dimensional electromagnetic structure into a cuboid laminate structure, achieving miniaturization. This planar structure is very easy to integrate with other RF circuits on the same system board via SMT (surface mount technology), greatly reducing the system's size, complexity, and overall cost. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of the overall structure of the phase shifter described in this invention;
[0018] Figure 2 This is a front view of the phase shifter described in this invention;
[0019] Figure 3 This is a schematic diagram of the structure of the first metal layer in the phase shifter of the present invention;
[0020] Figure 4 This is a schematic diagram of the structure of the second metal layer in the phase shifter of the present invention;
[0021] Figure 5 This is a schematic diagram of the structure of the third metal layer in the phase shifter of the present invention;
[0022] Figure 6 This is a schematic diagram illustrating the simulation results of the phase difference between the three- and four-port and one- and two-port phase shifters described in the embodiment.
[0023] Figure 7 This is a schematic diagram of the simulation results of the return loss at the first and third ports of the phase shifter described in the embodiment.
[0024] Figure 8 This is a schematic diagram showing the simulation results of the insertion loss at the one- and two-port and three- and four-port of the phase shifter described in the embodiment;
[0025] Figure 9 The diagram shows the electric field intensity distribution when a 100W excitation is applied to the three-port phase shifter described in the embodiment. Detailed Implementation
[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments.
[0027] This embodiment provides a high-power 0-π phase shifter composed of a multilayer circuit board, the overall structure of which is shown in the schematic diagram below. Figure 1 As shown, the front view is as follows Figure 2 As shown, the overall structure is a rectangular laminate with left-right symmetry. From top to bottom, it consists of a first metal layer, a first dielectric substrate, a second metal layer, a second dielectric substrate, and a third metal layer that are tightly bonded together. In this embodiment, the dielectric material used for the dielectric substrate is Rogers RO4350, with a relative permittivity of 3.66, a loss tangent of 0.004, and a substrate thickness of 0.56 mm.
[0028] A schematic diagram of the structure of the first metal layer is shown below. Figure 3As shown, it includes a bent microstrip line 301 and two high- and low-impedance microstrip lines. The bent microstrip line extends from the upper left edge to the upper right edge of the upper surface of the first dielectric substrate, and is parallel to the long side of the first dielectric substrate, with two gate-shaped protrusions in the middle. The first high- and low-impedance microstrip line 302 is parallel to the long side of the first dielectric substrate, and extends from the lower left edge to the right of the upper surface of the first dielectric substrate. From left to right, it consists of a first low-order microstrip line and a first high-order microstrip line connected in sequence. The second high- and low-impedance microstrip line 303 is parallel to the long side of the first dielectric substrate, and extends from the lower right edge to the left of the upper surface of the first dielectric substrate. From right to left, it consists of a second low-order microstrip line and a second high-order microstrip line connected in sequence. The first high- and low-impedance microstrip line and the second high- and low-impedance microstrip line are collinear but not connected to each other.
[0029] A schematic diagram of the structure of the second metal layer is shown below. Figure 4 As shown, two cutout regions are etched on the basis of fully covering the lower surface of the first dielectric substrate; the first cutout region (cutout region A) is located below the first higher-order microstrip line, and the second cutout region (cutout region B) is located below the second higher-order microstrip line; the length of the cutout region is the same as that of the higher-order microstrip line, and the width is greater than that of the higher-order microstrip line.
[0030] The structural diagram of the third metal layer is shown below. Figure 5 As shown, the coupling structure is located below the two hollowed-out areas; the coupling structure is a stepped microstrip line with adjustable width, and its length extends from the left edge of the first hollowed-out area to the right edge of the second hollowed-out area.
[0031] The first port is located on the upper left edge of the cuboid laminated structure and is connected to the left edge of the bent microstrip line; the second port is located on the upper right edge of the cuboid laminated structure and is connected to the right edge of the bent microstrip line; the third port is located on the lower left edge of the cuboid laminated structure and is connected to the left edge of the first low-order microstrip line; the fourth port is located on the lower right edge of the cuboid laminated structure and is connected to the right edge of the second low-order microstrip line; the first and third ports serve as input terminals, and a relative phase shift of approximately 180° can be generated between the second and fourth ports, and this phase shift can be precisely adjusted by adjusting the physical dimensions of the coupling structure.
[0032] Most importantly, the phase shifter described in this embodiment, through its unique structural design, naturally possesses the characteristic of built-in bandpass filtering response while achieving precise phase shifting. This filtering function is mainly achieved collaboratively through the following methods: the impedance distribution of the first and second high- and low-impedance microstrip lines (302, 303) constitutes multiple resonant units; simultaneously, the specific coupling strength and coupling frequency achieved through the precisely designed hollow area on the second metal layer and the coupling structure of the third metal layer jointly shape the frequency response of the entire circuit. Ultimately, this phase shifter can effectively filter out spurious signals outside the operating frequency band, allowing only RF signals of a specific frequency band to pass through with a predetermined 180° phase difference, achieving integrated phase shifting and filtering functions. This feature eliminates the need for additional filters in the system, further simplifying the RF front-end architecture and facilitating system miniaturization and performance optimization.
[0033] Multilayer circuit board processing steps:
[0034] First, a single-layer board is fabricated using a single-layer dielectric substrate and conventional printed circuit board (PCB) processing technology. The metal on the surface of the PCB is prefabricated according to the design, while the second layer of metal is cut out.
[0035] Assemble the circuit boards by stacking the processed circuit boards together in the corresponding order, and then using multilayer board processing technology to press them together to make them a whole.
[0036] The phase shifter described in this embodiment utilizes multilayer board technology to stack layers together, forming a gapless, tightly contacted structure, thus creating a high-power 0-π phase shifter structure composed of a multilayer circuit board. Furthermore, the number of circuit board layers can be adjusted appropriately according to actual needs to meet the requirements of different application scenarios. This structure ensures excellent heat dissipation paths and current carrying capacity by maintaining a large, complete ground plane, using a dielectric substrate with excellent thermal stability, and optimizing conductor width, thereby achieving high power capacity.
[0037] The phase shifter comprises two independent signal branches. The first branch is located at the top of the device and consists of a first port, a bent microstrip line, and a second port; the second branch is located at the bottom of the device and consists of a third port, a first high- and low-impedance microstrip line, a second high- and low-impedance microstrip line, and a fourth port. The two branches are electromagnetically isolated by a complete ground plane in between, ensuring that their signals are independent and do not interfere with each other.
[0038] During operation, radio frequency signals can be input simultaneously from both the first and third ports. For the first branch, the signal enters from the first port and propagates along the bent microstrip line to the second port for output. The physical length of this path and the "gate-like protrusion" structure together determine its reference phase shift. For the second branch, the signal enters from the third port, passes through the first low-order microstrip line, and reaches the first high-order microstrip line. Here, the signal energy undergoes strong electromagnetic coupling with the left half of the coupling structure of the third metal layer through the first hollow region on the second metal layer. The coupled signal then propagates along the stepped microstrip line of the third metal layer to its right half, and then is reverse-coupled back to the second high-order microstrip line through the second hollow region, finally outputting from the fourth port via the second low-order microstrip line.
[0039] The key lies in the unique transmission process the signal undergoes in the second branch: "high-low impedance microstrip line - coupling structure - high-low impedance microstrip line". Compared to direct transmission in the first branch, this path introduces additional electrical length and coupling phase shift. By precisely designing the coupling structure and the dimensions of the high-low impedance microstrip lines, this additional phase shift can be controlled, allowing the signal output from the fourth port to have a precise 180-degree phase reversal relative to the signal output from the second port.
[0040] The simulation results of the phase difference between the three- and four-port and one- and two-port phase shifters described in this embodiment are shown in the following diagram. Figure 6 As shown, within the operating frequency band, the phase difference between the two branches remains stable within the range of 180°±2.5°, exhibiting a small differential phase error. This indicates that the phase shifter possesses excellent weak dispersion characteristics. Furthermore, since the phase difference fluctuation is controlled within ±2.5°, this fully verifies that the interlayer coupling mechanism precisely controlled through the hollowed-out region effectively ensures the stability and consistency of the phase shift, overcoming the defect of easy phase drift in existing technologies.
[0041] The simulation results of the return loss at the first and third ports of the phase shifter described in this embodiment are shown in the diagram below. Figure 7 As shown, dB(S(1,1)) and dB(S(3,3)) characterize the input reflection characteristics of the first and third ports, respectively. Within the operating frequency band of the phase shifter, the return loss value of the third port is better than -14 dB, and the return loss value of the first port is better than -20 dB. This indicates that most of the energy of the input signal can effectively enter the phase shifter network, rather than being reflected back to the source, which essentially ensures the low insertion loss and high transmission efficiency of the circuit.
[0042] The simulation results of the insertion loss at the one- and two-port and three- and four-port ports of the phase shifter described in this embodiment are shown in the following diagram. Figure 8As shown, dB(S(2,1)) and dB(S(4,3)) characterize the insertion loss performance of the signal transmitted from the first port to the second port and from the third port to the fourth port, respectively, covering a frequency band of 8GHz-12GHz. Within the entire target operating frequency band, both insertion loss curves exhibit excellent performance, with values better than -1.2 dB. However, outside the operating frequency band, the insertion loss at the three and four ports deteriorates rapidly, indicating that the phase shifter also possesses bandpass filtering functionality, achieving functional integration.
[0043] The electric field intensity distribution diagram of the phase shifter described in this embodiment when a 100W excitation is applied to the three-port circuit is shown below. Figure 9 As shown in the figure, the electric field intensity distribution is relatively uniform throughout the entire transmission path. This indicates that electromagnetic energy is transmitted smoothly within the structure, without severe electric field concentration caused by structural abrupt changes or discontinuities, effectively avoiding the risk of dielectric breakdown or localized overheating. Although the electric field intensity is relatively strong in the hollowed-out area of the second metal layer and near its corresponding coupling structure in the third metal layer, its intensity value is far below the breakdown threshold of the dielectric substrate material, 3 × 10⁻⁶. 7 The energy exchange between the lower coupling structure and the upper microstrip line via the perforated window is efficient and safe, achieving precise phase shift while also meeting the stringent requirements for electric field control in high-power applications.
Claims
1. A high-power 0-π phase shifter composed of a multilayer circuit board, characterized in that, The overall structure is a rectangular laminate with a left-right symmetrical structure. From top to bottom, it consists of a first metal layer, a first dielectric substrate, a second metal layer, a second dielectric substrate, and a third metal layer that are tightly bonded together. The structure of the first metal layer includes a bent microstrip line and two high- and low-impedance microstrip lines. The bent microstrip line extends from the upper left edge to the upper right edge of the upper surface of the first dielectric substrate, and is parallel to the long side of the first dielectric substrate, with two gate-shaped protrusions in the middle. The first high- and low-impedance microstrip line is parallel to the long side of the first dielectric substrate, and extends from the lower left edge to the right of the upper surface of the first dielectric substrate. From left to right, it consists of a first low-order microstrip line and a first high-order microstrip line connected in sequence. The second high- and low-impedance microstrip line is parallel to the long side of the first dielectric substrate, and extends from the lower right edge to the left of the upper surface of the first dielectric substrate. From right to left, it consists of a second low-order microstrip line and a second high-order microstrip line connected in sequence. The first high- and low-impedance microstrip line and the second high- and low-impedance microstrip line are collinear but not connected to each other. The second metal layer has two hollow areas etched on the basis of fully covering the lower surface of the first dielectric substrate; The first hollowed-out region is located below the first high-order microstrip line, and the second hollowed-out region is located below the second high-order microstrip line; the length of the hollowed-out region is the same as that of the high-order microstrip line, and the width is greater than that of the high-order microstrip line. The third metal layer is a coupling structure located below the two hollow areas; the coupling structure is a stepped microstrip line with adjustable width, and its length extends from the left edge of the first hollow area to the right edge of the second hollow area.
2. The high-power 0-π phase shifter composed of a multilayer circuit board according to claim 1, characterized in that, The first port is located on the upper left edge of the cuboid laminated structure and is connected to the left edge of the bent microstrip line; the second port is located on the upper right edge of the cuboid laminated structure and is connected to the right edge of the bent microstrip line. The third port is located at the lower left edge of the cuboid laminated structure and is connected to the left edge of the first low-order microstrip line; the fourth port is located at the lower right edge of the cuboid laminated structure and is connected to the right edge of the second low-order microstrip line; the first and third ports serve as input terminals, and a 180° relative phase shift can be generated between the second and fourth ports.
3. The high-power 0-π phase shifter composed of a multilayer circuit board according to claim 1, characterized in that, The width of the hollowed-out area is six times the width of the high-order microstrip line.
4. The high-power 0-π phase shifter composed of a multilayer circuit board according to claim 1, characterized in that, The dielectric material selected for the first and second dielectric substrates is Rogers RO4350, with a relative permittivity of 3.66, a loss tangent of 0.004, and a thickness of 0.56 mm.