Compact high power capacity millimeter wave power combining network system and implementation method
By combining microstrip and waveguide technologies, a compact, high-power-capacity millimeter-wave power combining network was designed, solving the problem of balancing size and capacity in existing power combiners and achieving efficient and compact millimeter-wave signal processing.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHENGDU TAIBO LAI TECH CO LTD
- Filing Date
- 2026-03-27
- Publication Date
- 2026-07-03
AI Technical Summary
Existing millimeter-wave power combining networks have shortcomings in balancing high power capacity and structural compactness. Microstrip power combiners are small in size but have low capacity, while waveguide power combiners have large capacity but are not structurally flexible.
A hybrid integrated architecture is adopted, which combines a microstrip power divider with a waveguide power combiner. Low-power signals are distributed and amplified through a microstrip transmission line, while high-power signals are synthesized and filtered through a waveguide cavity, thereby achieving low-loss transmission and spurious suppression of high-power signals.
It achieves a balance between high power capacity and compact structure, with low overall insertion loss and high output power, making it suitable for millimeter-wave communication, radar and satellite communication and other fields.
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Figure CN121965085B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of millimeter-wave radio frequency technology, and in particular to a compact, high-power-capacity millimeter-wave power combining network system and its implementation method designed for the millimeter-wave frequency band. Background Technology
[0002] Millimeter waves are electromagnetic waves with frequencies between 30 GHz and 300 GHz, corresponding to wavelengths of approximately 1 to 10 millimeters. They are widely used in fields such as communications, radar, and sensors.
[0003] When millimeter waves are applied to fields such as communications and radar, in order to improve the communication transmission distance and radar detection distance of the system, it is necessary to increase the radio frequency transmission power of the system. Increasing the radio frequency transmission power requires the use of power combining networks, and the power capacity of the power combining network determines the upper limit of the power. Therefore, high power capacity power combining network technology is an important part of improving millimeter wave radio frequency systems.
[0004] Power combining networks amplify small power outputs significantly. Power combining networks, such as... Figure 1 As shown, it consists of three parts: an input power divider, a power amplifier, and an output power combiner.
[0005] The following example illustrates the function of a power combining network. First, a small signal, such as a 100mW signal, is input to a power divider. This 100mW signal is divided into multiple equal paths, for example, four paths, each containing 25mW. These four 25mW signals are then input to a power amplifier, for example, with a gain of 30dB. The four 25mW signals are then amplified into four 25000mW signals. Finally, these four amplified signals are combined by a final power combiner, combining the four 25000mW signals into a total of 100000mW, or 100W. Therefore, the power capacity of the power combiner is crucial.
[0006] Currently, in the millimeter-wave band, mainstream transmission lines use planar transmission lines such as microstrip lines. The advantages of these lines are their small size, flexible routing, and low cost. However, their power capacity is low, making them unsuitable for transmitting high-power signals. Waveguide transmission lines, on the other hand, are enclosed cavities with low loss and high power capacity, making them suitable for high-power signal transmission. Their disadvantages include a larger footprint and less flexible structural design compared to planar transmission lines.
[0007] Based on the aforementioned transmission line types, the mainstream power combiners currently include microstrip power combiners and waveguide power combiners. While microstrip-based power combiners offer a size advantage, their power capacity is lower than that of waveguide power combiners, such as CN117977147A. Waveguide-based power combiners, on the other hand, offer high power capacity but occupy a large volume, limiting their structural design, as seen in CN120914478A and CN221552140U. Therefore, designing a power combining network that simultaneously possesses high power capacity and a compact structure is a pressing issue. Summary of the Invention
[0008] The purpose of this invention is to overcome the shortcomings of the prior art described above: the advantages of the two types of power combiners are mutually exclusive, and it is impossible to simultaneously achieve both size and power capacity. This invention provides a compact, high-power-capacity millimeter-wave power combining network system and its implementation method. Compared with the prior art, it integrates the advantages of the aforementioned microstrip and waveguide power combiners, possessing the advantages of high power capacity, high integration, and compact structure.
[0009] The objective of this invention is achieved through the following technical solution:
[0010] A method for implementing a compact, high-power-capacity millimeter-wave power combining network includes the following steps:
[0011] Step S1: The input millimeter-wave low-power signal is divided into four equal channels by the first-stage microstrip power divider to obtain four low-power millimeter-wave signals; the first-stage microstrip power divider adopts a microstrip transmission line structure, which is suitable for flexible distribution and broadband matching of low-power signals;
[0012] Step S2: The four low-power millimeter-wave signals are input to the four independent amplification channels of the second-stage power amplifier for synchronous power amplification to obtain four high-power millimeter-wave signals; the second-stage power amplifier is used to provide high gain and high output power capability;
[0013] Step S3: The four high-power millimeter-wave signals are spatially combined using a third-stage waveguide power combiner to obtain a combined high-power millimeter-wave signal; the third-stage waveguide power combiner adopts a closed metal waveguide cavity structure, which is suitable for low-loss synthesis of high-power signals;
[0014] Step S4: The synthesized high-power millimeter-wave signal is passed through a fourth-stage waveguide filter to suppress spurious and harmonic noise, and outputs a high-purity millimeter-wave high-power signal; the fourth-stage waveguide filter adopts a waveguide cavity bandpass filter structure and is integrated at the end of the synthesis path;
[0015] The first-stage microstrip power divider and the second-stage power amplifier constitute the planar circuit part, and the third-stage waveguide power combiner and the fourth-stage waveguide filter constitute the three-dimensional waveguide cavity part. The two are integrated through a hybrid architecture to achieve high power capacity and compact structure of the overall system.
[0016] As a preferred embodiment, the first-stage microstrip power divider is a four-way Wilkinson power divider with an input return loss S11 better than -18dB in the 26GHz–40GHz frequency band and an amplitude consistency deviation of less than ±0.5dB between the four output ports.
[0017] As a preferred embodiment, the small-signal gain of each amplification channel of the second-stage power amplifier is 30dB±1dB in the 26GHz–40GHz frequency band, the input / output return loss S11 is better than -25dB, and the saturated output power of a single channel is not less than 25W; the second-stage power amplifier adopts a chip cavity package structure, and the cavity integrates an impedance matching network and a heat dissipation channel.
[0018] As a preferred embodiment, the third-stage waveguide power combiner adopts an H-plane T-junction four-in-one combining structure, and its combining port output power... With the power of each input channel and the maximum phase error between channels The relationship satisfies the following formula:
[0019]
[0020] in, This represents the total combined power at the output of the third-stage waveguide power combiner; Indicates the first The power input to the third-stage waveguide power combiner, ; This represents the summation of the power inputs from the four channels; This represents the maximum phase error between the four input signals, expressed in degrees (°). The structural efficiency factor of the third-stage waveguide power combiner characterizes the additional losses caused by waveguide discontinuities and surface roughness. Furthermore, through the design of equal electrical lengths for the four input waveguides, it ensures operation within the 26GHz-40GHz frequency band. Thus making .
[0021] As a preferred embodiment, the fourth-stage waveguide filter is a waveguide bandpass filter with a center frequency of Located in the 37.5GHz to 40.5GHz range, with a -3dB bandwidth (BW) of not less than 3GHz, and an in-passband insertion loss of [missing information]. satisfy:
[0022]
[0023] in, Indicates frequency Insertion loss at the location; Indicates the operating frequency; Indicates the filter at the center frequency The maximum insertion loss at the location; This represents the normalized insertion loss growth factor, whose physical meaning is: when the frequency deviates from the center frequency by a bandwidth (i.e., ... When BW), the insertion loss is relative to The maximum increment; and satisfying dB and ;
[0024] In addition, in the second harmonic frequency band The inhibition ratio is not less than 40dB.
[0025] As a preferred approach, the entire power combining network adopts a stacked integrated architecture: the first-stage microstrip power divider and the second-stage power amplifier are located in the upper planar circuit layer, and the third-stage waveguide power combiner and the fourth-stage waveguide filter are located in the lower metal cavity layer. The upper and lower layers are vertically interconnected and transmit millimeter-wave signals through the vertical probe transition structure.
[0026] As a preferred embodiment, the power combining network has an overall insertion loss of less than 1.5dB in the 26GHz–40GHz frequency band, and the total power capacity of the combined output is not less than 100W.
[0027] As a preferred embodiment, the overall dimensions of the power combining network are no greater than 50mm × 30mm × 15mm.
[0028] A compact, high-power-capacity millimeter-wave power combining network system, including:
[0029] The first-stage microstrip power divider is used to divide the input millimeter-wave low-power signal into four low-power millimeter-wave signals.
[0030] The second-stage power amplifier contains four independent amplification channels for synchronous power amplification of the four low-power millimeter-wave signals.
[0031] The third-stage waveguide power combiner is used to combine the four high-power millimeter-wave signals into one high-power millimeter-wave signal within a closed waveguide cavity.
[0032] The fourth-stage waveguide filter, cascaded at the output of the third-stage waveguide power combiner, is used to suppress spurious components and harmonic components in the synthesized signal.
[0033] The first-stage microstrip power divider and the second-stage power amplifier constitute a planar circuit subsystem, and the third-stage waveguide power combiner and the fourth-stage waveguide filter constitute a three-dimensional waveguide cavity subsystem. The planar circuit subsystem and the three-dimensional waveguide cavity subsystem are interconnected through a vertical transition structure to form a microstrip-waveguide hybrid integrated architecture.
[0034] As a preferred embodiment, the first-stage microstrip power divider is a four-way Wilkinson power divider with an input port characteristic impedance of 50Ω and an isolation of better than 20dB between the four output ports.
[0035] As a preferred embodiment, the third-stage waveguide power combiner is a rectangular waveguide H-plane four-in-one combiner, with the electrical lengths of its four input waveguides being equal; the fourth-stage waveguide filter is a waveguide bandpass filter; the third-stage waveguide power combiner and the fourth-stage waveguide filter share the same metal substrate and are integrally formed by precision milling or electrical discharge machining.
[0036] This invention offers at least the following advantages: The entire power combining network integrates multiple devices such as a microstrip power divider, power amplifier, waveguide power combiner, and filter into a single unit, resulting in high space utilization and a very compact overall structure. Simultaneously, the microstrip power divider ensures flexible input routing, reducing overall size. The waveguide power combiner can handle the high-power signal synthesized by the power amplifier while exhibiting low transmission loss. The final-stage filter suppresses spurious amplification from the power amplifier, improving signal quality. The entire structure boasts advantages such as high power capacity, high integration, and a compact design. Attached Figure Description
[0037] To reveal the technical details of the embodiments of the present invention, the accompanying drawings involved in the embodiments will be briefly described below. It should be emphasized that these drawings only present several embodiments of the present invention and should not be considered as defining the scope of the invention. For those skilled in the art, other related drawings can still be derived based on these drawings without inventive effort.
[0038] Figure 1 This is a diagram of the power combining network architecture;
[0039] Figure 2 This is the overall model of the power combining network;
[0040] Figure 3 The simulation results are for the overall power combining network.
[0041] Figure 4 The first-stage microstrip power divider and the second-stage power amplifier constitute a planar circuit section;
[0042] Figure 5Simulation results of the transmission performance of the planar circuit consisting of the first-stage microstrip power divider and the second-stage power amplifier;
[0043] Figure 6 Model of the third-stage vertical probe transition structure and waveguide power divider;
[0044] Figure 7 Simulation results for the third-stage vertical probe transition structure and waveguide power divider;
[0045] Figure 8 This is a simulation model of the final stage filter;
[0046] Figure 9 The simulation results are for the final stage filter;
[0047] Figure 10 This is a schematic diagram of the hierarchical structure of the overall model of the power combining network;
[0048] Figure 11 This is a schematic diagram of the overall dimensions of the power combining network model. Detailed Implementation
[0049] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the following description.
[0050] In the following description, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. However, it should be understood that the present disclosure is not limited to the specific forms shown herein. Rather, it should be understood to encompass various variations, equivalents, and / or alternatives to the embodiments of the present disclosure. In illustrating the drawings, the same reference numerals will be used to denote similar components.
[0051] In the various embodiments of this disclosure, the terms "first," "second," "the first," or "the second" are intended to modify different components and not to indicate order and / or importance, nor do they constitute a limitation on the respective components. For example, a first user equipment and a second user equipment represent different user equipments, although they both fall under the category of user equipment. Similarly, a first component may be named a second component, and a second component may be named a first component, without changing their essential attributes within the scope of this disclosure.
[0052] In this disclosure, terminology is used to describe specific embodiments and does not constitute a limitation thereof. In this context, the use of the singular form also encompasses the plural form, unless otherwise expressly stated herein. In the course of description, terms such as “comprising” or “having” are intended to indicate the presence of features, quantities, steps, operations, structural components, parts, or combinations thereof, and do not preclude the possibility or addition of one or more other features, quantities, steps, operations, structural components, parts, or combinations thereof.
[0053] It should be clarified that while the following description provides detailed specific information to aid in a comprehensive understanding of the exemplary embodiments, those skilled in the art will recognize that the exemplary embodiments can be implemented even without these specific details. For example, the system may be illustrated using block diagrams to avoid excessive detail that could obscure the clarity of the example. In other cases, to maintain the clarity of the example, unnecessary details of well-known processes, structures, and techniques may be omitted.
[0054] A method for implementing a compact, high-power-capacity millimeter-wave power combining network includes the following steps:
[0055] Step S1: The input millimeter-wave low-power signal is divided into four equal channels by the first-stage microstrip power divider to obtain four low-power millimeter-wave signals; the first-stage microstrip power divider adopts a microstrip transmission line structure, which is suitable for flexible distribution and broadband matching of low-power signals;
[0056] Step S2: The four low-power millimeter-wave signals are input to the four independent amplification channels of the second-stage power amplifier for synchronous power amplification to obtain four high-power millimeter-wave signals; the second-stage power amplifier is used to provide high gain and high output power capability;
[0057] Step S3: The four high-power millimeter-wave signals are spatially combined using a third-stage waveguide power combiner to obtain a combined high-power millimeter-wave signal; the third-stage waveguide power combiner adopts a closed metal waveguide cavity structure, which is suitable for low-loss synthesis of high-power signals;
[0058] Step S4: Pass the synthesized high-power millimeter-wave signal through a fourth-stage waveguide filter (see...). Figure 8 The fourth-stage waveguide filter performs spurious and harmonic suppression to output a high-purity millimeter-wave high-power signal; the fourth-stage waveguide filter adopts a waveguide cavity bandpass filter structure and is integrated at the end of the synthesis path; for example... Figure 9As shown, the final stage is a waveguide filter. Considering that the amplification effect of the preceding power amplifier will amplify both spurious signals and harmonics, a filter is integrated into the final stage to suppress spurious interference. The passband of the filter can be adjusted according to actual needs. In this implementation, the passband is 38GHz to 40GHz. Simulation results show that the filter has an out-of-band rejection greater than 50dB at 36GHz and 44GHz, effectively suppressing spurious signals from the preceding components and exhibiting good RF performance.
[0059] The first-stage microstrip power divider and the second-stage power amplifier constitute the planar circuit section, while the third-stage waveguide power combiner and the fourth-stage waveguide filter constitute the three-dimensional waveguide cavity section. These components, integrated through a hybrid architecture, achieve both high power capacity and a compact structure for the overall system. (See the power combining network architecture diagram.) Figure 1 .
[0060] This compact, high-power-capacity millimeter-wave power combining network achieves efficient conversion from low-power input to high-power output through a hybrid integrated architecture. First, a first-stage microstrip power divider splits the input low-power millimeter-wave signal into four equal paths, utilizing a microstrip transmission line structure for flexible allocation and broadband matching, ensuring uniform signal distribution. Next, the four independent channels of the second-stage power amplifier synchronously amplify each low-power signal, providing high gain and high output power capabilities. Subsequently, the third-stage waveguide power combiner employs a closed metal waveguide cavity structure to spatially combine the four high-power signals, effectively reducing transmission loss and supporting the synthesis of high-power signals. Finally, a fourth-stage waveguide filter further removes spurious and harmonic components from the synthesized signal, outputting a high-purity, high-power millimeter-wave signal. The overall system, through the organic combination of planar circuitry and a three-dimensional waveguide cavity, significantly improves system integration and structural compactness while maintaining high power capacity, making it suitable for high-frequency applications such as millimeter-wave communication, radar, and satellite communication. The overall simulation results of the power combining network are shown below. Figure 3 As shown, simulation results indicate that within the selected operating passband frequency range of 38GHz-40GHz, the S11 parameter is better than -15dB, exhibiting excellent RF transmission characteristics. Simultaneously, the filter demonstrates significant suppression effects outside the passband, effectively suppressing harmonic and spurious interference.
[0061] In a preferred embodiment, the first-stage microstrip power divider is a four-way Wilkinson power divider with an input return loss S11 better than -18dB in the 26GHz–40GHz frequency band and an amplitude consistency deviation of less than ±0.5dB between the four output ports.
[0062] The first-stage microstrip power divider employs a four-channel Wilkinson power divider structure. Its core function is to uniformly and stably split the input millimeter-wave small signal into four equal low-power signals, providing a foundation for subsequent multi-channel amplification and synthesis. Through the design of microstrip transmission lines and isolation resistors, the Wilkinson power divider effectively ensures good isolation and impedance matching between the output ports while achieving equal power distribution. Within a wide bandwidth range of 26 GHz to 40 GHz, the input return loss S of this power divider is... 11 The result is better than -18dB, indicating that most of the input signal can be effectively absorbed and distributed with minimal reflection, demonstrating excellent system matching performance. Simultaneously, the amplitude consistency deviation of the four output signals is controlled within ±0.5dB, indicating a highly balanced power distribution across channels. This is crucial for subsequent power combining efficiency; excessive amplitude differences between signals can lead to energy cancellation during combining, reducing the overall output power. Therefore, this power divider not only achieves wideband, low-reflection signal distribution but also lays a key foundation for the high efficiency and stability of the entire combining network.
[0063] In a preferred embodiment, the small-signal gain of each amplification channel of the second-stage power amplifier is 30dB±1dB in the 26GHz–40GHz frequency band, the input / output return loss S11 is better than -25dB, and the saturated output power of a single channel is not less than 25W; the second-stage power amplifier adopts a chip cavity package structure, and the cavity integrates an impedance matching network and a heat dissipation channel.
[0064] The second-stage power amplifier consists of four independent amplification channels. Its core function is to synchronously and efficiently amplify the four low-power millimeter-wave signals allocated from the first stage, providing sufficient energy for subsequent high-power synthesis. Within a wide operating frequency range of 26 GHz to 40 GHz, each channel provides approximately 30 dB of small-signal gain (with fluctuations not exceeding ±1 dB), ensuring stable and uniform signal amplification across the entire frequency band. Simultaneously, the return loss S at the input and output ports is minimal. 11 With a power output better than -25dB, the amplifier achieves excellent impedance matching with its preceding and following stages, significantly reducing signal reflections and improving transmission efficiency. More importantly, each channel can output at least 25W of RF power in saturation, demonstrating powerful high-power drive capability. To support such high power output, the amplifier employs a chip cavity package structure, integrating a sophisticated impedance matching network within the cavity to optimize high-frequency performance. It also incorporates efficient heat dissipation channels to effectively dissipate heat generated during chip operation, ensuring the reliability and stability of the system under high power and long-term operation. This design, balancing electrical performance and thermal management, is a key element in achieving the overall network's high power capacity.
[0065] In a preferred embodiment, the third-stage waveguide power combiner adopts an H-plane T-junction four-in-one combining structure, and its combining port outputs power... With the power of each input channel and the maximum phase error between channels The relationship satisfies the following formula:
[0066]
[0067] in, This represents the total combined power at the output of the third-stage waveguide power combiner, expressed in watts (W). Indicates the first The power input to the third-stage waveguide power combiner, expressed in watts (W). ; This represents the summation of the power inputs from the four channels; This represents the maximum phase error between the four input signals, expressed in degrees (°). The structural efficiency factor of the third-stage waveguide power combiner characterizes the additional losses caused by waveguide discontinuities and surface roughness. Furthermore, through the design of equal electrical lengths for the four input waveguides, it ensures operation within the 26GHz-40GHz frequency band. Thus making .
[0068] The third-stage waveguide power combiner employs a four-in-one combining structure with an H-plane T-junction, efficiently combining high-power millimeter-wave signals from four independent amplification channels into a single high-power signal. Through a precisely designed waveguide cavity and input waveguides of equal electrical length, the combiner ensures that all signals maintain phase consistency within the 26GHz to 40GHz operating frequency band, with a maximum phase error not exceeding 10°. This strict phase control ensures that the total output power after combining is close to the sum of the individual input powers, and due to excellent phase consistency, energy loss is minimal. The combining efficiency is highest when all four signals are completely in phase; even with some phase difference, the combiner's optimized design minimizes losses. Furthermore, the waveguide combiner's enclosed metal cavity structure exhibits low-loss characteristics, capable of withstanding high-power signal transmission without significant attenuation. A structural efficiency factor of 0.98 or higher further guarantees high efficiency during the combining process. The third-stage waveguide power combiner not only achieves efficient power combining but also provides the entire system with powerful high-power output capability, ensuring overall system performance and reliability. This combiner demonstrates excellent combining efficiency and stability over a wide bandwidth.
[0069] In a preferred embodiment, the fourth-stage waveguide filter is a waveguide bandpass filter with a center frequency of GHz, -3dB bandwidth BW=3GHz, BW represents the passband width of the filter, and its insertion loss within the passband. satisfy:
[0070]
[0071] in, Indicates frequency Insertion loss at the point, expressed in decibels (dB); Indicates the operating frequency, measured in gigahertz (GHz); Indicates the filter at the center frequency The maximum insertion loss at the specified location, expressed in decibels (dB). This represents the normalized insertion loss growth factor, which indicates the increase in insertion loss in decibels (dB) when the frequency deviates from the center frequency by one bandwidth. Its physical meaning is: when the frequency deviates from the center frequency by one bandwidth (i.e., ... When BW), the insertion loss is relative to The maximum increment; and satisfying dB and ;
[0072] In addition, in the second harmonic frequency band The inhibition ratio is not less than 40dB.
[0073] The fourth-stage waveguide filter employs a waveguide bandpass filter structure to perform spectral cleansing on the synthesized high-power millimeter-wave signal, suppressing harmonics and spurious components generated by the power amplifier, thereby outputting a high-purity useful signal. This filter has a center frequency of 39 GHz and a –3 dB bandwidth of 3 GHz (BW represents the passband width), covering the entire operating frequency band from 37.5 GHz to 40.5 GHz, ensuring that the useful signal passes through almost without loss. Within the passband, the filter exhibits extremely low insertion loss: the maximum loss at the center frequency does not exceed 0.3 dB, and the loss increases very slowly as the frequency deviates from the center; even at the edges of the passband, the loss increment is controlled within 0.05 dB, thanks to the low-loss and high-Q characteristics of the waveguide structure itself. More importantly, in the second harmonic band (i.e., 70 GHz and above), the filter provides a strong suppression capability of no less than 40 dB, effectively blocking high-frequency interference from entering subsequent systems. This high-performance filtering not only improves the spectral purity of the output signal, but also avoids spurious radiation interference to other frequency band devices. It is a key link in ensuring the electromagnetic compatibility and signal quality of the entire high-power millimeter-wave transmission link.
[0074] In a preferred embodiment, the first-stage microstrip power divider and the second-stage power amplifier are integrated on the same multilayer printed circuit board (see [link]). Figure 4The second-stage power amplifier is directly interconnected via a microstrip transmission line; the output of the second-stage power amplifier is connected to the input port of the third-stage waveguide power combiner via a vertical probe transition structure, achieving efficient power coupling from the planar microstrip circuit to the three-dimensional waveguide cavity. (See [link]). Figure 2 , Figure 10 and Figure 11 .
[0075] To balance system integration and signal transmission efficiency, the first-stage microstrip power divider and the second-stage power amplifier are integrated on a single multilayer printed circuit board (PCB) and directly interconnected via microstrip transmission lines. This eliminates the need for additional connectors or adapters, reducing overall size and lowering transmission loss and phase distortion of high-frequency signals at low power. After the four signals are boosted to high power by the amplifiers, a transition from planar circuitry to a three-dimensional waveguide structure is required to support high-power combining. A vertical probe transition structure is used to achieve this crucial connection: this structure uses precisely designed metal probes to vertically couple the microstrip line output ports on the PCB to the input ports of the waveguide cavity below, achieving efficient, low-reflection power transfer over a wide frequency band from 26 GHz to 40 GHz. Figure 5 As shown, simulation results of the transmission performance of the planar circuit consisting of the first-stage microstrip power divider and the second-stage power amplifier demonstrate that, in the frequency range of 26 GHz to 40 GHz, the typical value of the return loss parameter S11 is better than -20 dB, indicating that the first two stages of the planar structure have almost no signal reflection, and approximately 99% of the signal is transmitted. The parameters S21, S31, S41, and S51 in the figure are almost identical, indicating that the consistency of the four-way power divider and amplifier in the first two stages of the planar structure is very high. This hybrid integration method fully leverages the advantages of microstrip circuits in terms of flexible layout and ease of integration in the low-power range, while utilizing the characteristics of waveguide structures in terms of low loss and high power capacity in the high-power range. By bridging these two technical paths through vertical interconnection, it ensures signal integrity while achieving miniaturization and high performance of the entire device.
[0076] In a preferred embodiment, the third-stage waveguide power combiner and the fourth-stage waveguide filter are manufactured using an integrated metal processing technology, sharing a common waveguide sidewall for seamless connection; and heat dissipation fins or cooling channels are provided inside the metal cavities of the third-stage waveguide power combiner and the fourth-stage waveguide filter.
[0077] The third-stage waveguide power combiner and the fourth-stage waveguide filter are manufactured using an integrated metal processing technology, directly integrating them into the same metal substrate and sharing some waveguide sidewalls to form a seamless physical connection. This structure avoids the reflection, loss, and power leakage problems caused by flange connections or gaps between traditional discrete components, significantly improving signal transmission continuity and stability, especially in the millimeter-wave high-frequency band. Simultaneously, since the combined signal power reaches hundreds of watts, the system generates a significant amount of heat. Therefore, heat dissipation fins or cooling channels are specifically designed inside the metal cavity to efficiently dissipate the heat generated during high-power operation by increasing the heat dissipation area or introducing forced cooling (such as air cooling or liquid cooling). This structure not only enhances thermal management capabilities and ensures the reliability of the device under long-term high-power operation, but also further improves the overall integration, allowing the system to maintain high power capacity while retaining a compact and robust mechanical structure, making it ideal for millimeter-wave communication or radar systems with stringent requirements for size, efficiency, and stability.
[0078] In a preferred embodiment, the entire power combining network adopts a stacked integrated architecture: the first-stage microstrip power divider and the second-stage power amplifier are located on the upper planar circuit layer, and the third-stage waveguide power combiner and the fourth-stage waveguide filter are located on the lower metal cavity layer. The upper and lower layers are connected by the vertical probe (see [link]). Figure 6 and Figure 10 The transition structure enables vertical interconnection and millimeter-wave signal transmission. (See also...) Figure 7 Simulation results of the vertical probe transition structure and waveguide power divider show that, in the frequency range of 26 GHz to 40 GHz, the typical value of the return loss parameter S11 is better than -15 dB, indicating that the structure has almost no signal reflection, with about 97% of the signal being transmitted and only 3% of the signal being reflected. The parameters S21, S31, S41, and S51 in the figure are almost identical, indicating that the vertical structure of the waveguide has high consistency.
[0079] The entire power combining network adopts a layered integrated architecture, rationally arranging different functional modules according to signal power levels and structural characteristics: the upper layer is a planar circuit layer, integrating the first-stage microstrip power divider and the second-stage power amplifier, utilizing multi-layer printed circuit boards to achieve flexible distribution and efficient amplification of low-power signals, fully leveraging the advantages of microstrip circuits in miniaturization and high integration; the lower layer is a metal cavity layer, housing the third-stage waveguide power combiner and the fourth-stage waveguide filter, using a closed waveguide structure to withstand high-power signals and achieve low-loss combining and high-selectivity filtering. Vertical interconnection of millimeter-wave signals is achieved between the upper and lower layers through a vertical probe transition structure, completing the efficient conversion from planar microstrip to three-dimensional waveguide, significantly shortening the transmission path of high-power signals, and reducing parasitic effects and energy loss. This three-dimensional stacked design not only significantly reduces the overall size but also reduces electromagnetic interference between high and low power circuits through physical isolation, enabling the system to maintain high power capacity and high signal purity while achieving a compact structure, good thermal management, and high reliability, making it ideal for applications in space-constrained millimeter-wave communication base stations, vehicle-mounted radar, or satellite terminals.
[0080] In another embodiment, and in a preferred embodiment, the entire power combining network consists of a first-stage microstrip power divider, a second-stage power amplifier, a third-stage waveguide power combiner, and a fourth-stage waveguide filter connected sequentially. The third-stage waveguide power combiner employs an H-plane T-junction four-in-one structure for spatial power combining of four input signals. The fourth-stage waveguide filter is directly connected to the combiner output in a cascaded configuration to suppress harmonics and spurious signals. See the detailed structure for further details. Figure 2 The overall simulation results of the power combining network can be found in [link to simulation results]. Figure 3 .
[0081] In a preferred embodiment, the power combining network has an overall insertion loss of less than 1.5 dB in the 26 GHz–40 GHz frequency band, and the total power capacity of the combined output is not less than 100 W.
[0082] In a preferred embodiment, the overall dimensions of the power combining network are no greater than 50mm × 30mm × 15mm, which is significantly better than similar high-power millimeter-wave modules.
[0083] A compact, high-power-capacity millimeter-wave power combining network system, including:
[0084] The first-stage microstrip power divider is used to divide the input millimeter-wave low-power signal into four low-power millimeter-wave signals.
[0085] The second-stage power amplifier contains four independent amplification channels for synchronous power amplification of the four low-power millimeter-wave signals.
[0086] The third-stage waveguide power combiner is used to combine the four high-power millimeter-wave signals into one high-power millimeter-wave signal within a closed waveguide cavity.
[0087] The fourth-stage waveguide filter, cascaded at the output of the third-stage waveguide power combiner, is used to suppress spurious components and harmonic components in the synthesized signal.
[0088] The first-stage microstrip power divider and the second-stage power amplifier constitute a planar circuit subsystem, and the third-stage waveguide power combiner and the fourth-stage waveguide filter constitute a three-dimensional waveguide cavity subsystem. The planar circuit subsystem and the three-dimensional waveguide cavity subsystem are interconnected through a vertical transition structure to form a microstrip-waveguide hybrid integrated architecture.
[0089] This compact, high-power-capacity millimeter-wave power combining network system achieves a balance between high performance and small size by cleverly integrating planar circuitry and three-dimensional waveguide technology. The system first uses a microstrip power divider to evenly split the input low-power millimeter-wave signal into four paths, providing a foundation for subsequent parallel processing. Next, the four independent channels of the second-stage power amplifier synchronously amplify these four signals with high gain, outputting four high-power millimeter-wave signals. Since continued transmission of high-power signals on microstrip lines is prone to losses and breakdown risks, the system employs a third-stage waveguide power combiner to efficiently combine the four high-power signals into a single signal within a closed metal cavity, fully leveraging the low-loss and high-power-capacity advantages of the waveguide structure. Subsequently, a fourth-stage waveguide filter is directly cascaded at the combiner output to precisely filter out harmonics and spurious components generated by the power amplifier, ensuring the spectral purity of the output signal. The entire system is divided into two subsystems: a front-end planar circuit subsystem (including a power divider and power amplifier) responsible for flexible, wideband signal distribution and amplification, and a back-end three-dimensional waveguide cavity subsystem (including a synthesizer and filters) focusing on high-power processing and spectral cleansing. The two are tightly interconnected through a vertical transition structure, forming a microstrip-waveguide hybrid integrated architecture. This design avoids the power bottleneck of all-microstrip solutions and overcomes the bulky disadvantage of all-waveguide solutions, achieving high-efficiency, high-power, and highly integrated millimeter-wave signal synthesis and output within a limited space.
[0090] In a preferred embodiment, the first-stage microstrip power divider is a four-way Wilkinson power divider with an input port characteristic impedance of 50Ω and an isolation of better than 20dB between the four output ports.
[0091] In a preferred embodiment, the third-stage waveguide power combiner is a rectangular waveguide H-plane four-in-one combiner, with the electrical lengths of its four input waveguides being equal; the fourth-stage waveguide filter is a waveguide bandpass filter; the third-stage waveguide power combiner and the fourth-stage waveguide filter share the same metal substrate and are integrally formed by precision milling or electrical discharge machining.
[0092] In a preferred embodiment, the vertical transition structure is a tapered probe coupler or a slotted line coupler, used to achieve efficient millimeter-wave power transmission between the output of the second-stage power amplifier and the input of the third-stage waveguide power combiner.
[0093] In a preferred embodiment, the three-dimensional waveguide cavity subsystem is provided with an electromagnetic partition and a shielding layer to isolate electromagnetic interference between the second-stage power amplifier, the third-stage waveguide power combiner, and the fourth-stage waveguide filter; and the inner walls of the metal cavities of the third-stage waveguide power combiner and the fourth-stage waveguide filter are provided with heat dissipation fins or integrated cooling channels to enhance the thermal management capability under high-power operating conditions.
[0094] This invention provides a compact, high-power-capacity millimeter-wave power combining network. By organically combining microstrip circuits with a three-dimensional waveguide structure, it effectively balances high power processing capability with miniaturization requirements. From the front-end microstrip power divider and multi-channel power amplifier to the back-end integrated waveguide combiner and filter, the system achieves efficient signal distribution, amplification, combining, and purification. Within the 26GHz to 40GHz operating frequency band, it exhibits low overall insertion loss, high output power, and strong harmonic suppression, with an overall size not exceeding 50mm × 30mm × 15mm. (See [link]). Figure 11 This design breaks through the technical bottleneck of the traditional approach, which makes it difficult to achieve both "high power" and "small size," providing a reliable and efficient integrated solution for millimeter-wave communication, radar, and space-constrained high-power radio frequency systems.
[0095] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the invention. The above descriptions are merely preferred embodiments of the invention and are not intended to limit the invention. It should be noted that any modifications, equivalent substitutions, and improvements made within the spirit and principles of the invention should be included within the scope of protection of the invention.
Claims
1. A method for implementing a compact high power capacity millimeter wave power combining network, characterized by, Includes the following steps: Step S1: The input millimeter-wave low-power signal is divided into four equal channels by the first-stage microstrip power divider to obtain four low-power millimeter-wave signals; the first-stage microstrip power divider adopts a microstrip transmission line structure, which is suitable for flexible distribution and broadband matching of low-power signals; Step S2: The four low-power millimeter-wave signals are input to the four independent amplification channels of the second-stage power amplifier for synchronous power amplification to obtain four high-power millimeter-wave signals; the second-stage power amplifier is used to provide high gain and high output power capability; Step S3: The four high-power millimeter-wave signals are spatially combined using a third-stage waveguide power combiner to obtain a combined high-power millimeter-wave signal; the third-stage waveguide power combiner adopts a closed metal waveguide cavity structure, which is suitable for low-loss synthesis of high-power signals; Step S4: The synthesized high-power millimeter-wave signal is passed through a fourth-stage waveguide filter to suppress spurious and harmonic noise, and outputs a high-purity millimeter-wave high-power signal; the fourth-stage waveguide filter adopts a waveguide cavity bandpass filter structure and is integrated at the end of the synthesis path; The first-stage microstrip power divider and the second-stage power amplifier constitute the planar circuit part, and the third-stage waveguide power combiner and the fourth-stage waveguide filter constitute the three-dimensional waveguide cavity part. The two achieve high power capacity and compact structure of the overall system through a hybrid integrated architecture. The entire power combining network adopts a stacked integrated architecture: the first-stage microstrip power divider and the second-stage power amplifier are located in the upper planar circuit layer, and the third-stage waveguide power combiner and the fourth-stage waveguide filter are located in the lower metal cavity layer. The upper and lower layers are vertically interconnected and millimeter-wave signal transmission is achieved through a vertical probe transition structure.
2. The method for implementing a compact, high-power-capacity millimeter-wave power combining network according to claim 1, characterized in that: The first-stage microstrip power divider is a four-way Wilkinson power divider with an input return loss S11 better than -18dB in the 26GHz–40GHz frequency band and an amplitude consistency deviation of less than ±0.5dB between the four output ports.
3. The method for implementing a compact, high-power-capacity millimeter-wave power combining network according to claim 1, characterized in that: The small-signal gain of each amplification channel of the second-stage power amplifier is 30dB±1dB in the 26GHz–40GHz frequency band, the input / output return loss S11 is better than -25dB, and the saturated output power of a single channel is not less than 25W. The second-stage power amplifier adopts a chip cavity package structure, and the cavity integrates an impedance matching network and a heat dissipation channel.
4. The method for implementing a compact, high-power-capacity millimeter-wave power combining network according to claim 1, characterized in that: The third-stage waveguide power combiner adopts an H-plane T-junction four-in-one combination structure, and the output power of a combination port thereof is related to the power of each input channel and the maximum phase error between channels and satisfies the following formula: in, This represents the total combined power at the output of the third-stage waveguide power combiner; Indicates the first The power input to the third-stage waveguide power combiner, ; This represents the summation of the power inputs from the four channels; This represents the maximum phase error between the four input signals, expressed in degrees (°). The structural efficiency factor of the third-stage waveguide power combiner characterizes the additional losses caused by waveguide discontinuities and surface roughness. Furthermore, through the design of equal electrical lengths for the four input waveguides, it ensures operation within the 26GHz-40GHz frequency band. Thus making .
5. The method for implementing a compact, high-power-capacity millimeter-wave power combining network according to claim 1, characterized in that: The fourth-stage waveguide filter is a waveguide bandpass filter with a center frequency of... Located in the 37.5GHz to 40.5GHz range, with a -3dB bandwidth (BW) of not less than 3GHz, and an in-passband insertion loss of [missing information]. satisfy: in, Indicates frequency Insertion loss at the location; Indicates the operating frequency; Indicates the filter at the center frequency The maximum insertion loss at the location; This represents the normalized insertion loss growth factor, which is the factor that increases when the frequency deviates from the center frequency by one bandwidth (i.e., ...). When BW), the insertion loss is relative to The maximum increment; and satisfying and ; In addition, in the second harmonic frequency band The inhibition ratio is not less than 40dB.
6. The method for implementing a compact, high-power-capacity millimeter-wave power combining network according to claim 1, characterized in that: The power combining network has an overall insertion loss of less than 1.5dB in the 26GHz–40GHz frequency band, and the total power capacity of the combined output is not less than 100W.
7. A compact, high-power-capacity millimeter-wave power combining network system, characterized in that, include: The first-stage microstrip power divider is used to divide the input millimeter-wave low-power signal into four low-power millimeter-wave signals. The second-stage power amplifier contains four independent amplification channels for synchronous power amplification of the four low-power millimeter-wave signals. The third-stage waveguide power combiner is used to combine four high-power millimeter-wave signals into one high-power millimeter-wave signal within a closed waveguide cavity. The fourth-stage waveguide filter, cascaded at the output of the third-stage waveguide power combiner, is used to suppress spurious components and harmonic components in the synthesized signal. The first-stage microstrip power divider and the second-stage power amplifier constitute a planar circuit subsystem, and the third-stage waveguide power combiner and the fourth-stage waveguide filter constitute a three-dimensional waveguide cavity subsystem. The planar circuit subsystem and the three-dimensional waveguide cavity subsystem are interconnected through a vertical transition structure to form a microstrip-waveguide hybrid integrated architecture.
8. The compact, high-power-capacity millimeter-wave power combining network system according to claim 7, characterized in that: The first-stage microstrip power divider is a four-way Wilkinson power divider with an input port characteristic impedance of 50Ω and an isolation of better than 20dB between the four output ports.
9. The compact, high-power-capacity millimeter-wave power combining network system according to claim 7, characterized in that: The third-stage waveguide power combiner is a rectangular waveguide H-plane four-in-one combiner, with the electrical lengths of its four input waveguides being equal; the fourth-stage waveguide filter is a waveguide bandpass filter; the third-stage waveguide power combiner and the fourth-stage waveguide filter share the same metal substrate and are integrally formed by precision milling or electrical discharge machining.