Solid-state power amplifier for broadband noise suppression

Abstract

The invention discloses a solid-state power amplifier for broadband noise suppression. The solid-state power amplifier comprises an amplifying unit, a filtering unit, a transceiving switch, a matching network unit and a control unit for controlling which are connected with one another, the amplification unit comprises four stages of amplification units which are in a step-by-step driving amplification mode from the front end to the rear end, the first stage of amplification unit adopts a low-noise amplifier to amplify weak signals and reduce introduction of noise, the driving stage amplification unit and the pushing stage amplification unit further amplify preceding stage signals, and the final stage amplification unit adopts a power tube; the system further comprises a frequency hopping filter. According to the scheme, the frequency hopping filter is introduced into the power amplifier, broadband noise is suppressed, and the signal-to-noise ratio of the power amplifier is improved.

Description

Technical Field

[0001] This invention relates to the field of solid-state power amplifier technology, and more particularly to a solid-state power amplifier with broadband noise suppression. Background Technology

[0002] Solid-state power amplifiers (SPAs), as key components of wireless transmission systems, enhance signal energy through transistor power amplification. They are widely used in radio stations and radar systems to transmit data, voice, and text / image information. Broadband noise is a random, fluctuating signal with a wide frequency coverage accompanying the power amplifier's output signal, and its power spectral density is continuously distributed with frequency. Broadband noise is amplified synchronously with the amplifier chip, not only reducing the power amplifier's signal-to-noise ratio but also potentially degrading the receiver's sensitivity, severely impacting the system's communication quality. With the rapid development of modern communication technology, the electromagnetic environment is becoming increasingly harsh, placing higher demands on the performance of SPAs. Broadband noise is similar to white noise and cannot be filtered out. Therefore, researching methods to suppress broadband noise is of significant practical importance for SPAs. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a solid-state power amplifier with broadband noise suppression.

[0004] This invention is achieved using the following technical solution: A broadband noise-suppressed solid-state power amplifier includes an amplification unit, a filtering unit, a transceiver switch, a matching network unit, and a control unit connected to each other. The amplification unit includes a four-stage amplification unit in a step-by-step amplification mode from the front end to the back end. The first-stage amplification unit uses a low-noise amplifier to amplify weak signals and reduce the introduction of noise. The driving stage amplification unit and the driver stage amplification unit further amplify the previous stage signal. The final stage amplification unit uses a power transistor. Among them, the amplification unit is the core unit of the solid-state power amplifier, and the final stage amplification unit is the core unit of the entire power amplifier.

[0005] Specifically, it also includes frequency hopping filters, the number of which is set according to the gain of the solid-state power amplifier.

[0006] Specifically, the number of frequency hopping filters is set to two.

[0007] Specifically, the frequency hopping filter is positioned after each amplification unit at the front end of the solid-state power amplifier.

[0008] Specifically, the power transistor of the final stage amplifier unit is a gallium nitride power transistor.

[0009] Specifically, the filtering unit includes a filter and a coupler. The filter is selected as a low-pass filter or a band-pass filter, and the coupler includes two coupling ports that output coupled signals to detect the quality.

[0010] Specifically, the transceiver switch switches the power amplifier's transceiver channels, and the control unit provides logic control for the power amplifier unit; The control unit logic control includes power switching and functional protection, and the transceiver switch provides high isolation for the transceiver channel.

[0011] Specifically, the matching network unit performs impedance transformation on the gate and drain of the power transistor of the amplifier unit to match the impedance of the channel link to 50 ohms; at the same time, a digitally controlled attenuator is set to dynamically adjust the gain of the solid-state power amplifier.

[0012] The beneficial effects of this invention are as follows: This invention proposes a solid-state power amplifier based on a frequency hopping filter, which consists of an amplification unit, a filtering unit, a transceiver switch, a matching network unit, and a control unit. This solution introduces a frequency hopping filter into the power amplifier to suppress broadband noise and improve the signal-to-noise ratio of the power amplifier. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0014] Figure 1 This is a block diagram of the solid-state power amplifier in an embodiment of the present invention; Figure 2 This is a block diagram of the novel power amplifier in an embodiment of the present invention; Figure 3 This is a schematic diagram of power amplifier link gain allocation in an embodiment of the present invention; Figure 4 This is a schematic diagram of power amplifier broadband noise distribution in an embodiment of the present invention; Figure 5 This is a power amplifier ACPR test diagram in an embodiment of the present invention; Figure 6 This is a schematic diagram of the gain allocation of the novel power amplifier link in an embodiment of the present invention; Figure 7 This is a schematic diagram of the broadband noise distribution of the novel power amplifier in an embodiment of the present invention; Figure 8 This is a circuit diagram of the numerically controlled attenuator in an embodiment of the present invention; Figure 9 This is a design diagram of the power transistor in the final stage amplifier unit of this invention. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0016] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0017] The following is in conjunction with the appendix Figures 1-9 The following describes some embodiments of the present invention in detail. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0018] This invention proposes a broadband noise-suppressed solid-state power amplifier, which in one embodiment, as follows: Figure 1 As shown, it includes an amplifier unit, a filter unit, a transceiver switch, a matching network unit, and a control unit that are connected to each other.

[0019] In this embodiment, the amplification unit is the core unit of the solid-state power amplifier, comprising four stages of amplification in a step-by-step amplification mode. The first-stage amplification unit must be a low-noise amplifier, primarily used to amplify weak signals and reduce noise introduction. The noise figure is a crucial parameter for evaluating the noise performance of an amplifier, directly affecting the signal-to-noise ratio of the power amplifier's output signal. The driver and push-stage amplification units only need to further amplify the preceding signals; the final amplification unit is the core unit of the entire power amplifier, and the selection of its power transistors is particularly critical, determining the quality of the amplified signal.

[0020] In a preferred embodiment, a gallium nitride (GaN) power transistor is selected, which has the advantages of high gain, wide bandwidth, easy expansion, and high efficiency; the disadvantages are low impedance characteristics and poor reliability.

[0021] The filtering unit includes a filter and a coupler. The filter is either a low-pass or band-pass filter, with a fixed operating bandwidth, filtering out harmonics and spurious signals outside the operating frequency band. The coupler has two coupling ports; the coupled signal output from these ports is used to detect the quality of the output signal.

[0022] The function of the transceiver switch is to switch the power amplifier's transceiver channels; it also provides high isolation between the transceiver channels to ensure that the two channels do not interfere with each other.

[0023] Matching networks are used to match the impedance of the channel link to 50 ohms; port matching can adjust the power amplifier gain and improve the cascade impedance between the power amplifier and external devices. The impedance of the amplifying transistors in small-signal amplification units is generally 50 ohms, so impedance matching is not required. Gallium nitride (GaN) power transistors have low impedance, so their gate and drain need to be impedance-transformed through matching networks to ensure optimal operation. Digital attenuators dynamically adjust the power amplifier gain.

[0024] The control unit provides logic control for the power amplifier unit, performs power supply replacement, and provides functional protection, etc.

[0025] In this embodiment, the gain provided by the power amplifier in decibels amplifies both the useful signal and the broadband noise signal by the same amount. This reduces the power amplifier's signal-to-noise ratio, thus affecting the entire communication system. Since broadband noise can originate from the external environment or be generated by internal components, and is randomly distributed across various frequencies, it cannot be effectively filtered out using a filter with a fixed operating frequency.

[0026] Therefore, in another embodiment, a frequency-hopping filter is considered to be introduced into the power amplifier. A frequency-hopping filter is a filter that jumps with the operating frequency according to a certain sequence. It has a relatively narrow operating bandwidth, and the out-of-band rejection at the center frequency f0±15% is typically 25~30dB. The number of frequency-hopping filters can be determined according to the gain of the power amplifier. For example, if the gain of the power amplifier is 50dB, two frequency-hopping filters can be selected. For structural and cost considerations, the design considers introducing one frequency-hopping filter after each amplification stage in the power amplifier front-end, as shown in the block diagram below. Figure 2 As shown.

[0027] The following description is based on specific embodiments: Example 1 Taking the design of a power amplifier with a gain of 50dB and an output power of 100W as an example, this paper analyzes and explains the effect of frequency hopping filters on suppressing broadband noise.

[0028] The gain distribution of each stage of the power amplifier link is as follows: Figure 3 As shown, the power amplifier has four stages of amplification. The power transistor gain is 62dB. The matching network, digital attenuation, filtering unit, and transceiver switch have fixed losses. The gain of the entire power amplifier link is 50dB.

[0029] Broadband noise originates from the thermal noise of the power amplifier components themselves, nonlinear distortion, power supply noise, and external interference. The frequency of broadband noise generated by the components themselves can be determined from the component datasheet, and its impact on the power amplifier can be reduced through design, tuning, and manufacturing processes. Broadband noise generated by external interference has an unknown and random frequency; since there are no specific components to suppress it, the design, tuning, and manufacturing processes of the power amplifier have negligible effect on it.

[0030] The broadband noise distribution of the power amplifier is as follows Figure 4 As shown, the ambient noise is -145dB, and after amplification at each stage, the theoretical output broadband noise value is -95dB.

[0031] Linearity tests were performed on the power amplifier using QPSK modulation, a symbol rate of 1.6MHz, a roll-off factor of 0.25, and a signal bandwidth of 3.2MHz. The ACPR was -27dBc. Figure 5 As shown.

[0032] The new power amplifier incorporates two frequency-hopping filters, which inherently incur losses; each filter has a loss of 2dB. This reduces the overall power amplifier link gain by 4dB. The gain of the entire link can be adjusted by changing the attenuation value of the matching network to maintain this balance. For example... Figure 6 As shown.

[0033] After introducing the frequency-hopping filter, the other components of the power amplifier remain unchanged. The broadband noise distribution of the power amplifier is as follows: Figure 7 As shown. The ambient noise is -145dB. After amplification at each stage, the theoretical output broadband noise is -146dB. The output broadband noise is not degraded relative to the input broadband noise.

[0034] The power amplifier was linearly tested with QPSK modulation, a symbol rate of 1.6MHz, a roll-off factor of 0.25, and a signal bandwidth of 3.2MHz; the ACPR was -38dBc.

[0035] Furthermore, in this embodiment, the power amplifier's technical specifications are as follows: Operating frequency band: 225~400MHz Output power: 100W; Gain: 50dB Gain flatness: ±3dB Modulation method: QPSK EVM: ≤5%, Symbol Rate 1.6MHz, Roll-off Factor 0.25, Signal Bandwidth 3.2M Output harmonics: Harmonic suppression is not less than 60dBc at rated power; Broadband noise: ≤-140dBm / Hz Input standing wave: ≤2 Input voltage: DC+28V; Current: ≤12A; Operating temperature: -40℃~+60℃.

[0036] For the foregoing embodiments, in order to simplify the description, they are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, because according to this application, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions involved are not necessarily essential to this application.

[0037] The above embodiments describe the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Modifications and variations made by those skilled in the art without departing from the spirit and scope of the invention should be within the protection scope of the appended claims.

Claims

1. A broadband noise-suppressed solid-state power amplifier, characterized in that, It includes interconnected amplification units, filtering units, transceiver switches, matching network units, and control units; the amplification units include four-stage amplification units in a step-by-step amplification mode from the front end to the back end, wherein the first-stage amplification unit uses a low-noise amplifier to amplify weak signals and reduce the introduction of noise, the driving stage amplification unit and the driver stage amplification unit further amplify the previous stage signal, and the final stage amplification unit uses a power transistor.

2. The broadband noise-suppressed solid-state power amplifier as described in claim 1, characterized in that, It also includes frequency hopping filters, the number of which is set according to the gain of the solid-state power amplifier.

3. A broadband noise-suppressed solid-state power amplifier as described in claim 2, characterized in that, The number of frequency hopping filters is set to two.

4. A broadband noise-suppressed solid-state power amplifier as described in claim 3, characterized in that, The frequency hopping filter is placed after each amplification unit at the front end of the solid-state power amplifier.

5. A broadband noise-suppressed solid-state power amplifier as described in claim 1, characterized in that, The power transistor in the final stage amplifier unit is a gallium nitride power transistor.

6. A broadband noise-suppressed solid-state power amplifier as described in claim 1, characterized in that, The filtering unit includes a filter and a coupler. The filter is selected as a low-pass filter or a band-pass filter, and the coupler includes two coupling ports that output coupled signals to detect the quality.

7. A broadband noise-suppressed solid-state power amplifier as described in claim 1, characterized in that, The transceiver switch switches the power amplifier's transceiver channels, and the control unit provides logic control for the power amplifier unit.

8. A broadband noise-suppressed solid-state power amplifier as described in claim 5, characterized in that, The matching network unit performs impedance transformation on the gate and drain of the amplifier unit power transistor to match the impedance of the channel link to 50 ohms; at the same time, a digitally controlled attenuator is set to dynamically adjust the gain of the solid-state power amplifier.

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