A high-power power amplifier feed circuit structure

Abstract

This application discloses a high-power amplifier feed circuit structure, including a multilayer hybrid voltage board and high / low impedance lines. The high / low impedance lines consist of low-impedance and high-impedance lines, corresponding to a first and a second reference ground layer, respectively. The vertical distance between the second reference ground layer and the high / low impedance lines is greater than that between the first and second reference ground layers, to maintain the impedance of the high-impedance lines while increasing their physical width. This structure, by adjusting the reference ground layer distance, improves overcurrent capability and weakens voltage overshoot, achieving RF signal suppression of over 100dB in the target frequency band. It features a simple structure and low cost.

Description

Technical Field

[0001] This application relates to the field of microwave circuit technology, and in particular to a power amplifier feed circuit structure. Background Technology

[0002] In existing high-power amplifier power supply designs, a low-pass filter composed of high and low impedance lines is typically used. Ordinary high and low impedance line designs usually share the same reference ground plane (usually the ground plane closest to the circuit layer). According to transmission line theory, to achieve high impedance, the physical width of the high-impedance line must be designed to be very narrow. However, in high-power applications, excessively narrow high-impedance lines limit current carrying capacity, and the large inductive effect can lead to severe voltage overshoot, posing a risk of burning out the amplifier transistors. Summary of the Invention

[0003] The main objective of this application is to provide a method for constructing a power amplifier feed circuit, which aims to...

[0004] To achieve the above objectives, this application provides a high-power amplifier power supply circuit structure, comprising: Multilayer mixed pressure plate, and high and low impedance lines disposed on the multilayer mixed pressure plate; The high and low impedance lines include low impedance lines and high impedance lines; The low-resistivity line corresponds to the first reference formation, and the high-resistivity line corresponds to the second reference formation. The vertical distance between the second reference ground layer and the high and low impedance lines is greater than the vertical distance between the first reference ground layer and the high and low impedance lines, so as to increase the physical width of the high impedance lines while keeping the impedance of the high impedance lines unchanged.

[0005] Optionally, the multilayer hybrid platen includes multiple dielectric layers and multiple reference ground layers, and the high and low impedance lines are disposed on the surface of the top dielectric layer.

[0006] Optionally, an intermediate reference ground layer is provided between the first reference ground layer and the second reference ground layer. The intermediate reference ground layer has a clearance hole in the region corresponding to the high resistance line so that the high resistance line uses the second reference ground layer as a reference ground.

[0007] Optionally, the physical width of the high-resistivity line is greater than the width of the 50-ohm microstrip line.

[0008] Optionally, the physical width of the high-resistance line is several times that of a high-resistance line with the same impedance designed using a single reference ground.

[0009] Optionally, the multi-layer mixed-pressure plate has an 8-layer plate structure.

[0010] Optionally, the reference ground of the low-resistance line is the second layer of the 8-layer board structure, and the reference ground of the high-resistance line is the eighth layer of the 8-layer board structure.

[0011] Optionally, the substrate material of the multilayer mixed-pressure plate is RA300A, and the prepreg material is RNP280.

[0012] Optionally, the physical width of the high-resistance line is 0.75 mm, and the physical width of the low-resistance line is 0.77 mm.

[0013] Optionally, the power supply circuit structure has a radio frequency signal suppression capability of more than 100dB in the target frequency band.

[0014] This application proposes a high-power amplifier feeder circuit structure, comprising a multilayer hybrid voltage board and high / low impedance lines disposed on the multilayer hybrid voltage board. The high / low impedance lines include low-impedance lines and high-impedance lines. The low-impedance lines correspond to a first reference ground layer, and the high-impedance lines correspond to a second reference ground layer. The vertical distance between the second reference ground layer and the high / low impedance lines is greater than the vertical distance between the first reference ground layer and the high / low impedance lines, thereby increasing the physical width of the high-impedance lines while maintaining their impedance unchanged. This feeder circuit widens the physical size of the high-impedance lines by adjusting the reference layers on the multilayer hybrid voltage board, thereby reducing the inductive effect of the feeder circuit, increasing the overcurrent capability of the feeder lines, and weakening voltage overshoot. It achieves RF signal suppression capability of over 100dB in the target frequency band. It features a simple structure, low cost, high overcurrent capability, and strong resistance to voltage overshoot. Attached Figure Description

[0015] Figure 1 1. A top view of a power amplifier power supply circuit according to an embodiment of the power supply circuit structure of this application; Figure 2 1. A side view of the power supply circuit provided in an embodiment of the power supply circuit structure of the high-power amplifier of this application; Figure 3 The above is an application schematic diagram of an embodiment of the power amplifier feed circuit structure of this application. Figure 4 The following are examples of key dimensions of the power supply circuit provided in one embodiment of the power supply circuit structure for a high-power amplifier according to this application. Figure 5 The following are the S-parameters of the power supply circuit provided in an embodiment of the power supply circuit structure for a high-power amplifier according to this application; Figure 6 A comparative schematic diagram of a common high and low impedance line filter and a power supply circuit provided in an embodiment of the power amplifier power supply circuit structure of this application.

[0016] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0017] It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0018] Explanation of key terms: In this invention, "feed circuit" refers to a circuit structure that provides a DC power supply path for the power amplifier while isolating radio frequency signals. "High and low impedance lines" refers to a low-pass filter structure composed of alternating high and low characteristic impedance segments, utilizing impedance discontinuities to achieve radio frequency suppression. "Reference ground" refers to a metal layer in a microwave circuit that serves as a potential reference for the signal line; its position determines the characteristic impedance of the transmission line. "Multilayer hybrid laminate" refers to a printed circuit board made by laminating multiple layers of dielectric materials and conductive layers, such as common multilayer PCBs or LTCC substrates. "Voltage overshoot" refers to the phenomenon in a circuit where, due to the inductive effect, the instantaneous induced electromotive force generated during a drastic change in current exceeds the normal operating voltage.

[0019] Example 1 Please see Figures 1 to 6 This embodiment provides a power amplifier feed circuit structure. This feed circuit structure includes... Multilayer mixed pressure plate, and high and low impedance lines disposed on the multilayer mixed pressure plate; The high and low impedance lines (6) include low impedance lines (2) and high impedance lines (3). The low-resistivity line (2) corresponds to the first reference stratum, and the high-resistivity line (6) corresponds to the second reference stratum. The vertical distance between the second reference stratum and the high and low impedance line (6) is greater than the vertical distance between the first reference stratum and the high and low impedance line (6), so as to increase the physical width of the high impedance line (3) while keeping the impedance of the high impedance line (3) unchanged.

[0020] In one embodiment of this application, the multilayer hybrid platen includes multiple dielectric layers and multiple reference ground layers, and the high and low impedance lines are disposed on the surface of the top dielectric layer.

[0021] In one embodiment of this application, the multilayer hybrid platen includes multiple dielectric layers and multiple reference ground layers, and the high and low impedance lines are disposed on the surface of the top dielectric layer.

[0022] Specifically, the multilayer press plate can be made of LTCC (low-temperature co-fired ceramic) or other multilayer structures consisting of a dielectric material and a reference ground. For example, such as... Figure 1 , 2As shown in Figure 3, an 8-layer board power supply circuit structure is presented. In practical applications, the number of layers, the reference ground thickness, and the dielectric height of each layer can be adjusted as needed. The dielectric materials constituting the multilayer board can be selected according to requirements, such as using the Ruilong substrate RA300A or the prepreg RNP280.

[0023] The substrate (7) of the multilayer hybrid laminate is made of RA300A, a substrate from Ruilong, with a dielectric constant of 2.94 and a thickness of 0.238 mm. The prepreg (8) is made of RNP280, with a dielectric constant of 2.76 and a thickness of 0.119 mm. Specifically, as shown... Figure 2 As shown. The thickness of the first copper layer (16) (reference ground) is 0.018 mm. The thickness of the high and low impedance lines (6) is 0.018 mm, and the operating frequency band of the power amplifier (10) is 8-8.3 GHz. Specifically, the high and low impedance lines (6) are set on the surface of the multilayer board, and the thickness is, for example, 0.018 mm. The low impedance lines (2) and high impedance lines (3) are alternately connected to form a low-pass filter structure. By selecting materials with specific dielectric constants and thicknesses, the impedance characteristics of the transmission lines can be precisely controlled to meet the design requirements of specific frequency bands (such as 8-8.3 GHz). The structure of the multilayer hybrid board provides layout space for multiple reference grounds for the high and low impedance lines, making it possible to adjust the reference ground distance. Compared with single-layer or double-layer boards, it has a higher degree of design freedom. The discontinuity of high and low impedance is used to realize the reflection and suppression of radio frequency signals, which constitutes the basic functional unit of the feed circuit.

[0024] In one embodiment of this application, an intermediate reference ground layer is provided between the first reference ground layer and the second reference ground layer. The intermediate reference ground layer has a clearance hole (5) in the region corresponding to the high resistance line, so that the high resistance line (3) takes the second reference ground layer as the reference ground.

[0025] The reference ground of the low-resistance line (2) is the second layer of the 8-layer board structure. Specifically, taking an 8-layer board as an example, the reference ground of the low-resistance line (2) is selected from the second copper layer (4). The principle for selecting the reference ground of the high-resistance line is that it is farther away from the feed circuit than the reference ground of the low-resistance line. Selecting the first copper layer (16) as the reference ground of the high-resistance line (3) can achieve the maximum high-low impedance ratio and obtain greater RF suppression capability. The clearance via (5) is a hole opened between the second copper layer (4) and the third copper layer (9) to realize that the reference ground of the high-resistance line (3) is the first copper layer (16). In actual design, a suitable reference ground layer can be selected as needed. The low-resistance line (2) adopts a closer reference ground layer, which can achieve low impedance with a smaller line width, which conforms to the design convention of low-resistance lines and ensures the compactness of low-resistance lines.

[0026] Specifically, such as Figure 1 , 2As shown, the recommended reference ground for the high resistance line (3) is the first copper layer (16). The reference grounds of the third copper layer (9) and other intermediate copper layers are located in the area directly below the high resistance line. The clearance hole (5) needs to be "opened" or drilled to cut off the electrical connection, so that the electric field of the high resistance line (3) mainly terminates at the more distant first copper layer (16).

[0027] Therefore, by opening a window in the intermediate layer, the reference plane of the high-resistivity line is forcibly changed, which is the key means to achieve the technical feature of "the high-resistivity line reference ground being far from the feed circuit".

[0028] In one embodiment of this application, the reference ground of the high-resistance line is the eighth layer of the 8-layer plate structure. For example... Figure 1 , 2 As shown in Figures 3, 4, and 5, the reference ground of the high-resistance line (3) is selected based on the principle that it is farther from the feed circuit than the reference ground of the low-resistance line (2). Taking an 8-layer board as an example, the reference ground of the low-resistance line (2) is the second copper layer (4), and the reference ground of the high-resistance line (3) is the first copper layer (16). This combination can achieve the maximum high-low impedance ratio, thereby obtaining greater RF suppression capability. The reference ground of the low-resistance line (2) is the second copper layer (4). To achieve this, the reference ground of the third copper layer (9) in the middle needs to be "opened" in the area enclosed by the clearance hole (5). Thus, by setting the reference ground of the high-resistance line (3) on a more distant layer, the reference ground distance is increased, providing a physical basis for widening the line width while keeping the impedance unchanged.

[0029] In one embodiment of this application, the physical width of the high-resistivity line is greater than the width of the 50-ohm microstrip line. Specifically, in this design, the width of the 50-ohm microstrip line is 0.61 mm, while the physical width of the high-resistivity line in this embodiment is 0.75 mm. The high-resistivity portion of the feed line is already wider than the 50-ohm microstrip line. The feed circuit will not become a bottleneck for the overall circuit's overcurrent capability, solving the current bottleneck problem caused by the excessively narrow high-resistivity line in traditional designs.

[0030] In one embodiment of this application, the physical width of the high-resistance line is several times that of a high-resistance line with the same impedance designed using a single reference ground. Specifically, if both the low-resistance line (2) and the high-resistance line (3) use a second copper layer (4) as the reference ground (i.e., a common high- and low-resistance line), the width of the high-resistance line (3) is only 0.09 mm in order to achieve the same impedance ratio. However, using the solution of this application, the width of the high-resistance line (3) can reach 0.75 mm, which is more than 8 times that of the conventional solution. While ensuring that the high-resistance characteristics of the high-resistance line remain unchanged, a significant increase in physical size is achieved.

[0031] In one embodiment of this application, the physical width of the high-resistance line (3) is 0.75 mm, and the physical width of the low-resistance line is 0.77 mm. Specifically, based on classical theoretical calculations, the key dimensions are d1=0.77 mm, d2=5.23 mm, d3=2.1 mm, d4=6.71 mm, d5=2.26 mm, d6=4.89 mm, and d7=0.75 mm. These dimensional parameters verify the feasibility of the technical solution and ensure the reproducibility of the circuit performance.

[0032] Based on the above technical features, the technical effects of this embodiment are as follows: First, by adjusting the "reference ground" distance of the high-resistance line (i.e., using a more distant reference ground layer), its physical size can be increased while maintaining its high impedance characteristics. Since the current-carrying capacity of a conductor is proportional to its cross-sectional area (width), increasing the width of the high-resistance line (from 0.09mm to 0.75mm) directly and significantly improves the overcurrent capability of the feed structure, enabling it to meet the needs of high-power amplifier circuits. Second, the increased physical size significantly reduces the inductive characteristics of the high-resistance line. The induced electromotive force Vos is: In high-power amplifier circuits, the drain current changes drastically. Reducing the inductance L proportionally reduces the induced electromotive force, effectively mitigating voltage overshoot and lowering the risk of amplifier device breakdown, thus improving circuit reliability. Finally, this solution has a simple structure, requiring only adjustment of the reference ground plane and windowing design in the multilayer board design, without the need for additional active components or complex circuits, making it low-cost and easy to implement.

[0033] Example 2 Please see Figure 5 Based on Embodiment 1, this embodiment further limits the radio frequency suppression performance of the feed circuit structure.

[0034] In one embodiment of this application, the feed circuit structure has a radio frequency signal suppression capability of over 100dB in the target frequency band. Specifically, as shown... Figure 5 As shown in the S-parameter curve, this power supply circuit can provide extremely high isolation in the power amplifier operating frequency range (e.g., 8-8.3GHz).

[0035] Therefore, this power supply circuit not only has excellent overcurrent and voltage overshoot resistance, but also ensures that the core indicator of the power supply network, namely the radio frequency suppression capability, is not affected, and is even improved due to the optimization of the high and low impedance ratio, fully meeting the application requirements of high power and high power output scenarios.

[0036] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A power amplifier feed circuit structure, characterized in that, include: Multilayer mixed pressure plate, and high and low impedance lines disposed on the multilayer mixed pressure plate; The high and low impedance lines include low impedance lines and high impedance lines; The low-resistivity line corresponds to the first reference formation, and the high-resistivity line corresponds to the second reference formation. The vertical distance between the second reference ground layer and the high and low impedance lines is greater than the vertical distance between the first reference ground layer and the high and low impedance lines, so as to increase the physical width of the high impedance lines while keeping the impedance of the high impedance lines unchanged.

2. The power supply circuit structure according to claim 1, characterized in that, The multilayer hybrid platen includes multiple dielectric layers and multiple reference ground layers, and the high and low impedance lines are disposed on the surface of the top dielectric layer.

3. The power supply circuit structure according to claim 2, characterized in that, An intermediate reference ground layer is provided between the first reference ground layer and the second reference ground layer. The intermediate reference ground layer has a clearance hole in the region corresponding to the high resistance line so that the high resistance line uses the second reference ground layer as a reference ground.

4. The power supply circuit structure according to claim 1, characterized in that, The physical width of the high-resistivity line is greater than that of the 50-ohm microstrip line.

5. The power supply circuit structure according to claim 1, characterized in that, The physical width of the high-resistance line is several times that of the same impedance high-resistance line designed with a single reference ground.

6. The power supply circuit structure according to claim 1, characterized in that, The multi-layer mixed-pressure plate has an 8-layer plate structure.

7. The power supply circuit structure according to claim 6, characterized in that, The reference ground of the low-resistivity line is the second layer of the 8-layer plate structure, and the reference ground of the high-resistivity line is the eighth layer of the 8-layer plate structure.

8. The power supply circuit structure according to claim 1, characterized in that, The substrate material of the multilayer mixed-pressure plate is RA300A, and the prepreg material is RNP280.

9. The power supply circuit structure according to claim 1, characterized in that, The physical width of the high-resistivity line is 0.75 mm, and the physical width of the low-resistivity line is 0.77 mm.

10. The power supply circuit structure according to claim 1, characterized in that, The power supply circuit structure has a radio frequency signal suppression capability of more than 100dB in the target frequency band.

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