A broadband high frequency spatial power combiner

Abstract

The application discloses a broadband high-frequency space power combiner, which comprises a partition plate and two bases, the partition plate is arranged between the two bases, the base and the partition plate form two waveguide cavities, a first PCB plate is arranged in each waveguide cavity, a radio frequency circuit is arranged on the first PCB plate, a second PCB plate is arranged on the two surfaces of the partition plate facing the first PCB plate, and an EBG structure is arranged on the second PCB plate. The EBG structure is arranged on the surface of the partition plate facing the PCB plate of the radio frequency circuit, so that the influence of resonance modes on the combiner can be effectively avoided; the EBG structure is arranged to inhibit resonance, so that the size of the waveguide cavity does not need to be reduced, and the EBG structure does not need to separate the waveguide cavities, and the circuit layout on the first PCB plate is not affected. The application can be widely applied in the field of power combiners.

Description

Technical Field

[0001] This invention relates to the field of power combiners, and in particular to a broadband high-frequency spatial power combiner. Background Technology

[0002] The output power and gain of a power amplifier chip roll off as the application frequency increases. To meet the high output power requirements of millimeter-wave systems, power combiners can be used to combine the power of multiple power amplifier chips to achieve high power levels. Currently, among power combining technologies, spatial combining technology can meet the design requirements of multiple chips and high power. A typical spatial power combining technology uses a tray-type waveguide-based spatial power combiner for spatial power combining.

[0003] Existing tray-type waveguide-based spatial power combiners typically operate in the C-band to Ku-band (4GHz-18.1GHz). To prevent resonance in the cavity housing the power amplifier chip array, absorbing material is usually attached to the cavity walls, and the cavity size is reduced. However, attaching absorbing material to the cavity walls leads to a decrease in combiner power and gain, while reducing the cavity size means sacrificing the layout space for chips and bias circuits, making power combining at higher frequencies difficult to achieve with spatial power combiners. Summary of the Invention

[0004] To address the aforementioned technical problems, the present invention aims to provide a broadband high-frequency spatial power combiner that avoids resonance occurring in the combiner's operating frequency band, thereby realizing a broadband high-frequency spatial power combiner.

[0005] The technical solution adopted by this invention to solve its technical problem is:

[0006] A broadband high-frequency spatial power combiner includes a partition and two bases. The partition is disposed between the two bases, and the bases and the partition form two waveguide cavities. Each waveguide cavity is provided with a first PCB board, and the first PCB board is provided with radio frequency circuits. The two sides of the partition facing the first PCB board are provided with a second PCB board, and the second PCB board is provided with an EBG structure.

[0007] Furthermore, the radio frequency circuit includes an antenna array, a microstrip matching network, and an MMIC array, with the antenna array connected to the MMIC array via the microstrip matching network.

[0008] Furthermore, the antenna array is in the form of a fin.

[0009] Furthermore, the fin line form includes any one of monopolar fin lines, bipolar fin lines, and antipolar fin lines.

[0010] Furthermore, the EBG structure includes an array of EBG units.

[0011] Furthermore, the EBG unit includes a metal layer, a dielectric layer, and vias. The vias are disposed in the dielectric layer. The metal layer includes a top metal layer and a bottom metal layer. The metal layers are disposed on two surfaces of the dielectric layer connected by the vias. The bottom metal layer is disposed on the surface of the dielectric layer facing the second PCB board.

[0012] Furthermore, the EBG unit also includes an air cavity located on the side of the top metal layer opposite to the dielectric layer.

[0013] Furthermore, the radio frequency circuit also includes a bias circuit, which is composed of SMT surface mount components.

[0014] The beneficial effects of this invention are:

[0015] The present invention discloses a broadband high-frequency spatial power combiner, which can effectively avoid the influence of resonant modes on the combiner by setting an EBG structure on the PCB board with the partition facing the RF circuit PCB board. By setting an EBG structure on the PCB board, it is not necessary to reduce the size of the waveguide cavity, and the EBG structure does not need to separate the waveguide cavity, so it will not affect the circuit layout of the first PCB board. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of a broadband high-frequency spatial power combiner according to the present invention;

[0017] Figure 2 This is a schematic diagram of the transverse cross-sectional structure of a broadband high-frequency spatial power combiner according to the present invention;

[0018] Figure 3 This is a schematic diagram of the EBG structure of a broadband high-frequency spatial power combiner according to the present invention;

[0019] Figure 4 This is a Brillouin diagram of the EBG unit of a broadband high-frequency spatial power combiner according to the present invention;

[0020] Figure 5 This is a schematic diagram of the simulation results of a broadband high-frequency spatial power synthesizer according to the present invention.

[0021] Among them, 101 is the base; 102 is the partition; 103 is the first PCB board; 104 is the second PCB board; 301 is the EBG unit; 302 is the dielectric layer; 303 is the top metal layer; 304 is the bottom metal layer; 305 is the via; and 306 is the air cavity. Detailed Implementation

[0022] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings:

[0023] Reference Figure 1 and Figure 2 The present invention provides a broadband high-frequency spatial power combiner, including a partition 102 and two bases 101. The partition 102 is disposed between the two bases 101. The bases 101 and the partition form two waveguide cavities. Each waveguide cavity is provided with a first PCB board 103. The first PCB board 103 is provided with radio frequency circuits. The two sides of the partition 102 facing the first PCB board 103 are provided with a second PCB board 104. The second PCB board 104 is provided with an EBG structure.

[0024] The second PCB board 104 faces the first PCB board 103, so it will not divide the waveguide cavity space where the first PCB board 103 is located, nor will it reduce the size of the waveguide cavity, so that the circuit layout of the first PCB board 103 is not affected.

[0025] As an optional implementation, the radio frequency circuit includes an antenna array, a microstrip matching network, and an MMIC array, with the antenna array connected to the MMIC array via the microstrip matching network.

[0026] The radio frequency circuit's antenna array includes a power-dividing antenna array and a power-combining antenna array, used to implement waveguide transmission mode (TE). 10 The power divider antenna array is located at the waveguide input end, enabling the conversion between TE mode and microstrip mode (TEM mode transmission mode). 10 The conversion from TEM mode to TE mode is achieved by placing the combined antenna array at the waveguide output end. 10 Switching between analog and digital transmission modes.

[0027] The microstrip matching network is connected to both the antenna array and the MMIC array to transform the output impedance of the antenna array into the input impedance of the MMIC array.

[0028] In one embodiment of the present invention, an MMIC array includes four MMIC power amplifier chips for power amplification.

[0029] As an optional implementation, the antenna array is in the form of a fin.

[0030] Among them, the fin line forms include any one of monopolar fin lines, bipolar fin lines, and antipolar fin lines.

[0031] Each first PCB board features two fin-type power divider antenna arrays and a power combiner antenna array. The curvature of the fins is determined using frequency domain analysis (SDA) and small reflection theory. To obtain the shortest fin length, the impedance gradient in the microstrip matching network follows the Klopfenstein form. Through the above fin design, this embodiment of the invention enables the design of a broadband spatial power combiner.

[0032] As an optional implementation, the EBG structure includes an array of EBG units 301.

[0033] Reference Figure 3 The EBG unit 301 includes a metal layer, a dielectric layer 302, and a via 305. The via 305 is disposed in the dielectric layer 302. The metal layer includes a top metal layer 303 and a bottom metal layer 304. The metal layer is disposed on two surfaces of the dielectric layer 302 connected by the via 305. The bottom metal layer 304 is disposed on the surface of the dielectric layer 302 facing the second PCB board 104.

[0034] The EBG unit also includes an air cavity 306, which is located on the side of the top metal layer 303 opposite to the dielectric layer 302.

[0035] Reference Figure 4 The Brillouin plot of EBG unit 301 is shown below. The horizontal axis of the Brillouin plot represents electromagnetic waves with incident angles from 0 to 180°, which is proportional to the phase constant. The vertical axis represents the frequency, and the slope is proportional to the phase velocity. When the slope of the Brillouin plot is close to 0, it indicates that electromagnetic waves at the corresponding incident angle are cut off at the corresponding frequency. For example... Figure 3 As shown, the slopes of electromagnetic waves at frequencies of 24.1 GHz and 34 GHz are only 0 for all incident angles, and there are no solutions within the range of 24.1–34 GHz. Therefore, the bandgap bandwidth of the EBG element on the horizontal axis of this Brillouin plot is 24.1–34 GHz. Furthermore, 24.1 GHz and 34 GHz are the upper and lower cutoff frequencies of the electromagnetic bandgap, respectively, implying that there are no field solutions within the electromagnetic bandgap, meaning that there are no electromagnetic waves with any incident angle within the 24.1–34 GHz electromagnetic bandgap.

[0036] According to Bloch's theorem, the array of EBG units 301 has the same bandgap characteristics as a single EBG unit. In the embodiments of the present invention, by setting an EBG structure on a PCB board above the radio frequency circuit, the spatial power combiner only has TEM modes during operation, and the microstrip matching network cannot couple out other modes, thus achieving the suppression effect of resonant modes.

[0037] As an optional implementation, the first PCB board is further provided with a bias circuit, which is composed of SMT surface mount components.

[0038] In an embodiment of the present invention, a broadband high-frequency spatial power combiner includes the aforementioned base 101, partition 102, first PCB board 103, and second PCB board 104. Simulation of the broadband high-frequency spatial power combiner yields the following results: Figure 4 As shown.

[0039] Reference Figure 4 The broadband high-frequency spatial power combiner described herein achieves power combining within a Ka-band waveguide (26.5–40 GHz), while existing tray-type waveguide spatial power combiners typically operate in the C-band to Ku-band (4 GHz–18.1 GHz). Furthermore, this embodiment of the invention has no outgoing resonant point in the 25.5–32 GHz frequency range. Therefore, this broadband high-frequency spatial power combiner, by incorporating a second PCB board 104 with an EBG structure, achieves spatial power combining at higher frequencies and has the potential for application in even higher frequency bands. Simultaneously, due to its spurious mode suppression effect, this invention exhibits superior flatness and more stable performance compared to existing spatial power combiners.

[0040] On the other hand, the embodiments of the present invention further broaden the bandwidth of the spatial power combiner by using an EBG structure in conjunction with an antenna array design in the form of fins with broadband characteristics.

[0041] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A broadband high frequency spatial power combiner, characterized by, The application relates to a waveguide cavity, which comprises a partition plate and two bases, the partition plate is arranged between the two bases, the base and the partition plate form two waveguide cavities, a first PCB plate is arranged in each waveguide cavity, a radio frequency circuit is arranged on the first PCB plate, a second PCB plate is arranged on two surfaces of the partition plate which face the first PCB plate, and an EBG structure is arranged on the second PCB plate. The EBG structure comprises an array of EBG units. The EBG unit comprises a metal layer, a dielectric layer and a via, the via is arranged in the dielectric layer, the metal layer comprises a top metal layer and a bottom metal layer, the metal layer is arranged on two surfaces of the dielectric layer which are communicated by the via, and the bottom metal layer is arranged on the surface of the dielectric layer which faces the second PCB plate. The EBG unit further comprises an air cavity, and the air cavity is located on the side of the top metal layer which is away from the dielectric layer. The EBG structure forms an electromagnetic band gap of 24.1 GHz to 34 GHz, so as to suppress the resonant mode in the waveguide cavity, and only TEM transmission mode exists in the radio frequency circuit.

2. A broadband high frequency spatial power combiner as recited in claim 1, wherein, An antenna array, a microstrip matching network and an MMIC array are arranged in the radio frequency circuit, and the antenna array is connected with the MMIC array through the microstrip matching network.

3. A broadband high frequency spatial power combiner as recited in claim 2, wherein, The antenna array is in the form of a fin line.

4. A broadband high frequency corporate power combiner as recited in claim 3, wherein, The fin line form comprises any one of a single pole fin line, a double pole fin line and a pair of pole fin line.

5. A broadband high frequency spatial power combiner as recited in claim 1, wherein, A bias circuit is further arranged on the first PCB plate, and the bias circuit is composed of SMT patch elements.

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