Wideband RF amplifier circuit and design method with full-band stability

Abstract

This disclosure provides a broadband RF amplifier circuit and design method with full-band stability. The broadband RF amplifier circuit includes a transistor, a low-frequency stabilization network, a mid-frequency stabilization network, and a high-frequency stabilization network. By designing the synergistic interaction parameters of the low-frequency, mid-frequency, and high-frequency stabilization networks, the broadband RF amplifier circuit achieves a stability factor μ greater than 1 across the entire band. In this technical solution, the three stabilization networks act on different frequency bands respectively, synergistically ensuring that the RF amplifier circuit has a stability factor μ greater than 1 across the entire band with minimal gain loss. Furthermore, it provides a low-cost and highly reusable technical path for the high-performance design of broadband RF amplifier circuits.

Description

Technical Field

[0001] This disclosure relates to the field of radio frequency amplifiers, and in particular to a broadband radio frequency amplifier circuit and design method with full-band stability. Background Technology

[0002] Radio frequency (RF) power amplifiers are core modules in wireless communication systems, radar systems, and RF front-ends, and their performance directly affects the communication quality and reliability of the entire system. With the increasing demands for operating bandwidth and integration in applications such as 5G communication, satellite navigation, and electronic countermeasures, broadband RF amplifiers are receiving growing attention. However, broadband RF amplifiers are prone to parasitic oscillations both within and outside their operating band, especially when unpredictable feedback paths are introduced in the low-frequency or high-frequency bands, potentially leading to circuit instability or even complete failure. Therefore, achieving absolute stability across the entire frequency band while ensuring key performance indicators such as gain, noise, and linearity of the RF amplifier is a crucial element in RF circuit design. Summary of the Invention

[0003] This disclosure provides a broadband radio frequency amplifier circuit and design method, which has the advantages of full-band stability and bandpass gain, as well as low gain loss.

[0004] According to one aspect of this disclosure, a broadband radio frequency amplifier circuit with full-band stability is provided, comprising: a transistor, said transistor being a bipolar junction transistor (BJT) or a field-effect transistor (FET); a low-frequency stabilization network connected between the base of the BJT or the gate of the FET and a reference ground, for suppressing low-frequency oscillations across the full band; a mid-frequency stabilization network connected between the emitter of the BJT or the source of the FET and a reference ground, for suppressing mid-frequency oscillations across the full band; and a high-frequency stabilization network connected between the collector of the BJT or the drain of the FET and a reference ground, for suppressing high-frequency oscillations across the full band. In this process, by designing the synergistic interaction parameter relationship between the low-frequency band stabilization network, the mid-frequency band stabilization network, and the high-frequency band stabilization network, the stability factor μ of the broadband RF amplifier circuit is made greater than 1 across the entire frequency band. The synergistic interaction parameter relationship is determined as follows: the initial stability factor μ of the RF amplifier circuit excluding the low-frequency band stabilization network, the mid-frequency band stabilization network, and the high-frequency band stabilization network is determined for each frequency band; the gap between the initial stability factor μ and the stability threshold of the stability factor μ for each frequency band is determined; the target contribution of each stabilization network to the stability factor μ is determined based on the size or proportion of the gap for each frequency band; and the component parameters of each stabilization network are designed based on the target contribution of each stabilization network, thereby realizing the synergistic interaction parameter relationship.

[0005] According to at least one embodiment of the broadband radio frequency amplifier circuit of this disclosure, the size of the notch is directly proportional to the target contribution.

[0006] According to at least one embodiment of the broadband radio frequency amplifier circuit of the present disclosure, the gain loss of the broadband radio frequency amplifier circuit does not exceed 2dB compared to the case where the low-frequency band stabilization network, mid-frequency band stabilization network and high-frequency band stabilization network are not provided.

[0007] According to at least one embodiment of the broadband radio frequency amplifier circuit of the present disclosure, the intermediate frequency stabilization network includes a first transmission line connected between the emitter of the bipolar junction transistor or the source of the field-effect transistor and a reference ground, for introducing negative feedback at the emitter of the bipolar junction transistor or the source of the field-effect transistor to suppress oscillations in the intermediate frequency band.

[0008] According to at least one embodiment of the broadband RF amplifier circuit of this disclosure, the intermediate frequency (IF) stabilization network is designed such that: when the length of the first transmission line decreases, the gain of the IF band is reduced and the bandwidth is widened; when the length of the first transmission line increases, the gain of the IF band is increased and the bandwidth is narrowed.

[0009] According to at least one embodiment of the broadband radio frequency amplifier circuit of the present disclosure, the low-frequency stabilization network includes a first resistor and a first capacitor connected in series.

[0010] According to at least one embodiment of the broadband radio frequency amplifier circuit of this disclosure, the low-frequency stabilization network is designed such that: when the first resistor and the first capacitor decrease, the gain of the low-frequency band is increased, and when the first resistor and the first capacitor increase, the gain of the low-frequency band is decreased.

[0011] According to at least one embodiment of the broadband radio frequency amplifier circuit of the present disclosure, the high-frequency stabilization network includes a second resistor, a second capacitor, and a second transmission line, wherein the second resistor and the second capacitor are connected in parallel to form a parallel circuit, and the parallel circuit is connected in series with the second transmission line.

[0012] According to at least one embodiment of the broadband radio frequency amplifier circuit of this disclosure, the high-frequency band stabilization network is designed such that: when the second capacitor decreases and the second resistor increases, the gain of the high-frequency band is increased, and when the second capacitor increases and the second resistor decreases, the gain of the high-frequency band is decreased.

[0013] A broadband radio frequency amplifier circuit according to at least one embodiment of the present disclosure further includes a gate bias network, one end of which is connected to the base of the bipolar junction transistor or the gate of the field-effect transistor, and the other end of which is connected to a bias voltage terminal for providing a DC bias voltage to the base of the bipolar junction transistor or the gate of the field-effect transistor.

[0014] According to at least one embodiment of the broadband radio frequency amplifier circuit of the present disclosure, the gate bias network includes a gate bias inductor and a gate bias resistor connected in series.

[0015] A broadband radio frequency amplifier circuit according to at least one embodiment of the present disclosure further includes a drain bias network, one end of which is connected to the collector of the bipolar junction transistor or the drain of the field-effect transistor, and the other end of which is connected to a power supply voltage terminal for providing DC operating current to the collector of the bipolar junction transistor or the drain of the field-effect transistor.

[0016] A broadband radio frequency amplifier circuit according to at least one embodiment of the present disclosure further includes an input DC blocking capacitor and an output DC blocking capacitor. The input DC blocking capacitor is connected between the base of the bipolar junction transistor or the gate of the field-effect transistor and the radio frequency signal input terminal, for allowing the radio frequency signal to pass through and isolating the bias voltage of the bias voltage terminal from the radio frequency signal input terminal. The output DC blocking capacitor is connected between the collector of the bipolar junction transistor or the drain of the field-effect transistor, the high-frequency band stabilization network, and the radio frequency signal output terminal.

[0017] According to another aspect of this disclosure, a design method for a broadband radio frequency amplifier circuit is provided, comprising: determining an initial stability factor μ for each frequency band in the low-frequency, mid-frequency, and high-frequency bands when the broadband radio frequency amplifier circuit does not include the low-frequency band stabilization network, the mid-frequency band stabilization network, and the high-frequency band stabilization network; determining a gap between the initial stability factor μ for each frequency band and a stability threshold of the stability factor μ; determining a target contribution of each stabilization network to the stability factor μ based on the size or proportion of the gap for each frequency band; and designing the component parameters of each stabilization network based on the target contribution of each stabilization network to the stability factor μ.

[0018] The RF amplifier circuit according to this disclosure has at least the following advantages.

[0019] The low-frequency stabilization network primarily suppresses oscillations in the low and mid-frequency bands across the entire frequency band. The mid-frequency stabilization network introduces negative feedback in the mid-frequency band to suppress instability. The high-frequency stabilization network specifically absorbs parasitic energy in the high-frequency band to suppress oscillations. These three stabilization networks act on different frequency bands respectively, working together to ensure that the stability factor μ of the RF amplifier circuit is greater than 1 across the entire frequency band from DC to tens of GHz, thus achieving unconditional stability across the entire frequency band.

[0020] By coordinating the frequency responses of low-frequency, mid-frequency, and high-frequency stabilization networks, strong feedback is formed across the entire frequency band to effectively suppress oscillations, while weak feedback is formed within the entire frequency band to preserve gain. This achieves absolute stability across the entire frequency band while keeping gain loss at a low level. As the test results above show, compared to the case without these three stabilization networks, the gain loss of the RF amplifier circuit disclosed in this invention is only about 1.5dB, significantly lower than the 3dB to 6dB or more gain loss typically caused by traditional stabilization methods, effectively achieving a balance between stability and high gain.

[0021] By employing the frequency selectivity of low-frequency, mid-frequency, and high-frequency stabilization networks, these three networks not only suppress oscillations but also actively participate in adjusting the gain frequency characteristics of the RF amplifier circuit. This ensures that the gain remains flat across the entire target band and spontaneously rolls off outside the target band. Therefore, the RF amplifier circuit of this disclosure directly achieves bandpass gain response characteristics without the need for additional filters, transforming the stabilization networks, originally used only to consume gain and prevent oscillations, into functional components that achieve both frequency selection and gain curve shaping. Attached Figure Description

[0022] The accompanying drawings illustrate exemplary embodiments of the present disclosure and, together with the description thereof, serve to explain the principles of the present disclosure. These drawings are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this specification.

[0023] Figure 1 This is an example of a radio frequency amplifier circuit in the prior art.

[0024] Figure 2 This is another example of a radio frequency amplifier circuit in the prior art.

[0025] Figure 3 This is a circuit diagram of a radio frequency amplifier circuit according to one embodiment of the present disclosure.

[0026] Figure 4 This is a circuit diagram of a radio frequency amplifier circuit according to another embodiment of the present disclosure.

[0027] Figure 5 The results of the stability factor μ are shown without the addition of low-frequency, mid-frequency, and high-frequency stabilization networks to the RF amplifier circuit.

[0028] Figure 6 The measurement results of the stability factor μ after adding a mid-frequency stabilization network to the RF amplifier circuit are shown.

[0029] Figure 7 The measurement results of the stability factor μ after adding a low-frequency stabilization network to the RF amplifier circuit are shown.

[0030] Figure 8 The measurement results of the stability factor μ after adding a high-frequency stabilization network to the RF amplifier circuit are shown.

[0031] Figure 9 It shows Figure 8 The gain curve of the corresponding RF amplifier circuit.

[0032] Figure 10This is a flowchart of a design method for a broadband radio frequency amplifier circuit according to an embodiment of the present disclosure. Detailed Implementation

[0033] The present disclosure will now be described in further detail with reference to the accompanying drawings and examples. It should be understood that the specific examples described herein are for illustrative purposes only and are not intended to limit the scope of the disclosure. Furthermore, it should be noted that, for ease of description, only the parts relevant to the present disclosure are shown in the accompanying drawings.

[0034] It should be noted that, where there is no conflict, the embodiments and features described in this disclosure can be combined with each other. The technical solutions of this disclosure will now be described in detail with reference to the accompanying drawings and embodiments.

[0035] Existing broadband RF amplifiers often sacrifice absolute gain to suppress potential parasitic oscillations, and it is difficult to simultaneously achieve both in-band gain flatness and out-of-band absolute stability. Traditional single stabilization networks (such as simple series resistors or source / emitter degraded inductors) suffer from significant gain reduction or limited frequency response characteristics. Furthermore, when multiple independent stabilization networks are superimposed, the complex electromagnetic interactions between them lead to long debugging iteration cycles and make it difficult to guarantee absolute stability of the RF amplifier across the entire frequency band (especially over an extremely wide range from DC to tens of GHz operating frequencies).

[0036] The implementation of broadband RF amplifiers is mainly achieved by improving the feedback network architecture or introducing multi-order filters.

[0037] Improved feedback network architecture, such as in Figure 1 As shown, in Figure 1 The example presents an ultrawideband low-noise amplifier architecture combining a narrowband low-noise amplifier with parallel resistor negative feedback. This design is based on a cascode narrowband low-noise amplifier with a source-degraded inductor, utilizing a large feedback resistor Rf to reduce the quality factor of the input resonant circuit, thereby widening the operating bandwidth. Since its input impedance is primarily determined by the transistor's characteristic frequency and the source-degraded inductor, the feedback resistor value can be much larger than in traditional feedback architectures, thus achieving wideband matching while minimizing noise figure degradation. While this design effectively suppresses instability, the trade-off is a direct loss of the RF amplifier's absolute gain. Even with parallel resistor negative feedback, although the bandwidth is widened to some extent by reducing the quality factor, the presence of the feedback loop inevitably limits further increases in power gain and negatively impacts the noise figure.

[0038] The design of introducing multi-order filters, such as Figure 2 As shown. In Figure 2The example provides a design for an ultrawideband low-noise amplifier based on a multi-order filter synthesis network (bandpass filter synthesis). In this design, the entire input matching network is equivalent to a third-order Chebyshev bandpass filter. Figure 2 As shown, this design absorbs the parasitic capacitances of the transistors (such as gate-source capacitances) used as amplifying diodes, as well as the source degenerate inductance network used for noise optimization, and incorporates them as part of a multi-stage reactive network for overall resonance. However, this design employs a multi-stage LC filter network (such as a third-order Chebyshev filter) for impedance transformation and stability compensation. While this design achieves good input matching over a wide bandwidth, it introduces a large number of reactive components, resulting in extremely complex electromagnetic interactions between the various stabilization networks. This not only significantly increases the chip area but also requires an extremely long iterative debugging cycle during the layout design phase, making it difficult to reliably guarantee absolute stability across the entire frequency band.

[0039] This disclosure provides a broadband RF amplifier circuit with full-band stability and bandpass gain characteristics. By innovatively combining a series RC stabilization network and a parallel RC stabilization network, along with a transmission line degradation structure, and utilizing the synergistic coupling effect among these three components, a stability factor μ>1 is achieved within the target band, while simultaneously obtaining bandpass response characteristics with gain flatness across the target band and spontaneous gain roll-off outside the target band. According to the technical solution of this disclosure, the circuit structure is simple, requires no additional active components, and is easy to integrate. It fundamentally solves the technical pain point of balancing gain flatness, full-band stability, and design complexity in broadband RF front-end systems, significantly improving the reliability of the system in applications such as 5G communication and radar. In this application, "full-band" refers to the entire band range of the target band (target operating frequency band).

[0040] To facilitate description and make the technical solutions of this disclosure easier to understand, the terminology of this disclosure will be explained before describing the technical solutions of this disclosure.

[0041] Radio frequency (RF) amplifier: An electronic circuit or device used to amplify radio frequency (RF) signals, increasing the power or voltage of the input RF signal to achieve the desired power level. Key performance indicators of an RF amplifier include gain, bandwidth, and stability. Gain is the amplification factor, usually expressed in dB. The stability factor μ is a necessary and sufficient condition for determining whether an RF amplifier is unconditionally stable. When μ > 1, the amplifier will not oscillate under any passive load or source impedance conditions, i.e., it is unconditionally stable.

[0042] According to embodiments of this disclosure, a radio frequency amplifier circuit with full-band stability is provided. In embodiments of this disclosure, the transistor is the amplifying element (active device) of the radio frequency amplifier circuit, and can be a bipolar junction transistor (BJT) or a field-effect transistor (MOSFET). In this disclosure, the number of active devices can be one, that is, only one transistor. Figure 3 A schematic diagram of a radio frequency amplifier circuit according to an embodiment of the present disclosure is shown.

[0043] exist Figure 3 In the embodiments shown, the transistor is a field-effect transistor, and the RF amplifier circuit is an RF amplifier circuit with full-band stability and bandpass gain characteristics.

[0044] like Figure 3 As shown, the RF amplifier circuit includes a field-effect transistor 110, a low-frequency stabilization network 200, a mid-frequency stabilization network 300, and a high-frequency stabilization network 400.

[0045] The gate of the field-effect transistor 110 serves as the input terminal for the radio frequency signal, and the drain serves as the output terminal for the radio frequency signal.

[0046] One end of the low-frequency stabilization network 200 is connected to the gate G of the field-effect transistor 110, and the other end is connected to reference ground GND. The low-frequency stabilization network 200 is used to suppress low-frequency oscillations in the full-band RF amplifier circuit. The low-frequency stabilization network 200 may include a first resistor 210 and a first capacitor 220. The first resistor 210 and the first capacitor 220 are connected in series to form the low-frequency stabilization network 200. That is, one end of the first resistor 210 is connected to the gate G of the field-effect transistor 110, the other end of the first resistor is connected to one end of the first capacitor 220, and the other end of the first capacitor 220 is connected to reference ground GND. In this disclosure, the low-frequency stabilization network 200 is mainly used to suppress potential low-frequency oscillations.

[0047] The intermediate frequency (IF) stabilization network 300 is connected between the source S of the field-effect transistor 110 and the reference ground GND, and is used to suppress oscillations in the IF band of the aforementioned full-band RF amplifier circuit. The IF stabilization network 300 may include a source degradation transmission line (the transmission line may be, for example, a microstrip line), for example, in the form of a first transmission line 310. One end of the first transmission line 310 may be connected to the source S of the field-effect transistor 110, and the other end of the first transmission line 310 may be connected to the reference ground GND. The IF stabilization network 300 is used to introduce negative feedback at the source S of the field-effect transistor 110, suppressing IF band instability by providing bandwidth negative feedback.

[0048] A high-frequency stabilization network 400 is connected between the drain D of the field-effect transistor 110 and the reference ground GND to suppress high-frequency oscillations across the entire frequency band. The high-frequency stabilization network 400 may include a second resistor 420, a second capacitor 430, and a second transmission line 410. Specifically, the second resistor 420 and the second capacitor 430 are connected in parallel and then in series with the second transmission line 410 to form the high-frequency stabilization network 400. One end of the second resistor 420 is connected to one end of the second transmission line 410, and the other end is connected to the reference ground GND. One end of the second capacitor 430 is connected to one end of the second transmission line 410, and the other end is connected to the reference ground GND. The other end of the second transmission line 410 is connected to the drain D of the field-effect transistor 110; specifically, the other end of the second transmission line 410 can be connected to the drain D of the field-effect transistor 110 via an output DC blocking capacitor 520. In this disclosure, the high-frequency stabilization network 400 is specifically used to absorb parasitic energy in the high-frequency band, thereby suppressing high-frequency oscillations.

[0049] As an example, the low-frequency band mentioned in this disclosure can be the range from the lower limit of the target band to the lower limit of the mid-frequency band, the mid-frequency band can be the target center frequency itself and its vicinity, and the high-frequency band can be the range from the upper limit of the mid-frequency band to the upper limit of the target band. Here, the target band refers to the specific frequency range in which the RF amplifier circuit is designed to amplify the normal (desired) signal. In this disclosure, the target band can range from DC to tens of GHz.

[0050] In this disclosure, the low-frequency stabilization network 200, the mid-frequency stabilization network 300, and the high-frequency stabilization network 400 work synergistically. Specifically, the low-frequency stabilization network 200 suppresses low-frequency oscillations, the mid-frequency stabilization network 300 suppresses mid-frequency oscillations, and the high-frequency stabilization network 400 suppresses high-frequency oscillations. This results in a stability factor μ greater than 1 across the entire frequency band for the RF amplifier circuit, with a flat gain across the entire band and automatic gain roll-off outside the entire band. In this disclosure, the coordinated frequency responses of the low-frequency stabilization network 200, the mid-frequency stabilization network 300, and the high-frequency stabilization network 400 create strong feedback outside the entire frequency band to efficiently suppress oscillations, and weak feedback within the entire frequency band to preserve gain. As will be seen from the following description, compared to the case without the low-frequency stabilization network 200, the mid-frequency stabilization network 300, and the high-frequency stabilization network 400, the gain loss of the RF amplifier circuit of this disclosure does not exceed 2 dB.

[0051] like Figure 3As shown, the RF amplifier circuit of this embodiment also includes a gate bias network 600. The gate bias network 600 is connected between the gate G of the field-effect transistor 110 and the bias voltage terminal. The gate bias network 600 is used to provide a DC operating voltage to the gate G of the field-effect transistor 110. The gate bias network 600 may include a gate bias resistor 610 and a gate bias inductor 620. The gate bias resistor 610 and the gate bias inductor 620 are connected in series to form the gate bias network 600. One end of the gate bias resistor 610 is connected to the bias voltage terminal, and the other end of the gate bias resistor 610 is connected to one end of the gate bias inductor 620, the other end of the gate bias inductor 620 being connected to the gate G of the field-effect transistor 110. In this disclosure, the bias voltage terminal is used to input the bias voltage Vbias, and the RF signal input terminal RFI is used to input the RF signal.

[0052] like Figure 3 As shown, the RF amplifier circuit of this embodiment also includes a drain bias network 700. The drain bias network 700 is connected between the drain D of the field-effect transistor 110 and the power supply voltage terminal. The drain bias network 700 is used to provide a DC operating voltage VDD to the drain D of the field-effect transistor 110. The drain bias network 700 may include a drain bias resistor 710 and a drain bias inductor 720. The drain bias resistor 710 and the drain bias inductor 720 are connected in series to form the drain bias network 700. One end of the drain bias resistor 710 is connected to the bias voltage terminal, and the other end of the drain bias resistor 710 is connected to one end of the drain bias inductor 720, the other end of the drain bias inductor 720 being connected to the drain D of the field-effect transistor 110. In this disclosure, the bias voltage terminal is used to provide the DC operating voltage VDD.

[0053] Furthermore, the RF amplifier circuit of this embodiment also includes an input DC blocking capacitor 510 and an output DC blocking capacitor 520. The input DC blocking capacitor 510 is disposed between the RF signal input terminal RFI and the gate G of the field-effect transistor 110, allowing the RF signal to pass through while also isolating the gate bias voltage terminal from the RF signal input terminal. The output DC blocking capacitor 520 is disposed between the drain D of the field-effect transistor 110 and the RF signal output terminal RFO. The output DC blocking capacitor 520 allows the RF signal to pass through and be delivered to the RF signal output terminal RFO, while completely blocking the leakage of the transistor drain's DC operating voltage VDD to the RF signal output terminal RFO.

[0054] According to further embodiments of this disclosure, the transistor can be a bipolar junction transistor, such as... Figure 4 As shown. The RF amplifier circuit includes a bipolar junction transistor 120, a low-frequency stabilization network 200, a mid-frequency stabilization network 300, and a high-frequency stabilization network 400.

[0055] The base of the bipolar junction transistor 120 serves as the input terminal for radio frequency signals, and the collector serves as the output terminal for radio frequency signals.

[0056] One end of the low-frequency stabilization network 200 is connected to the base B of the bipolar junction transistor 120, and the other end is connected to reference ground GND. The low-frequency stabilization network 200 is used to suppress low-frequency oscillations in the aforementioned full-band RF amplifier circuit. The low-frequency stabilization network 200 may include a first resistor 210 and a first capacitor 220. The first resistor 210 and the first capacitor 220 are connected in series to form the low-frequency stabilization network 200. That is, one end of the first resistor 210 is connected to the base B of the bipolar junction transistor 120, the other end of the first resistor is connected to one end of the first capacitor 220, and the other end of the first capacitor 220 is connected to reference ground GND. In this disclosure, the low-frequency stabilization network 200 is mainly used to suppress potential low-frequency oscillations.

[0057] The intermediate frequency (IF) stabilization network 300 is connected between the emitter E of the bipolar junction transistor 120 and the reference ground GND, and is used to suppress oscillations in the IF band of the aforementioned full-band RF amplifier circuit. The IF stabilization network 300 may include a source degradation transmission line, for example, in the form of a first transmission line 310. One end of the first transmission line 310 may be connected to the emitter E of the bipolar junction transistor 120, and the other end of the first transmission line 310 may be connected to the reference ground GND. The IF stabilization network 300 is used to introduce negative feedback at the emitter E of the bipolar junction transistor 120, suppressing IF band instability by providing wideband negative feedback.

[0058] A high-frequency stabilization network 400 is connected between the collector C of the bipolar junction transistor 120 and the reference ground GND to suppress high-frequency oscillations across the entire frequency band. The high-frequency stabilization network 400 may include a second resistor 420, a second capacitor 430, and a second transmission line 410. Specifically, the second resistor 420 and the second capacitor 430 are connected in parallel and then in series with the second transmission line 410 to form the high-frequency stabilization network 400. One end of the second resistor 420 is connected to one end of the second transmission line 410, and the other end is connected to the reference ground GND. One end of the second capacitor 430 is connected to one end of the second transmission line 410, and the other end is connected to the reference ground GND. The other end of the second transmission line 410 is connected to the collector C of the bipolar junction transistor 120; specifically, the other end of the second transmission line 410 can be connected to the collector C of the bipolar junction transistor 120 via an output DC blocking capacitor 520. In this disclosure, a high-frequency stabilization network 400 is used specifically to absorb parasitic energy in the high-frequency band, thereby suppressing oscillations in the high-frequency band.

[0059] As an example, the low-frequency band mentioned in this disclosure can range from DC to near the lower limit of the target band, the mid-frequency band can be the target center frequency itself and its vicinity, and the high-frequency band can be the range from near the upper limit of the target band to tens of GHz. Here, the target band refers to the specific frequency range in which the RF amplifier circuit is designed to amplify the normal (desired) signal. In this disclosure, the full-band range can be from DC to tens of GHz.

[0060] In this disclosure, the low-frequency stabilization network 200, the mid-frequency stabilization network 300, and the high-frequency stabilization network 400 work synergistically. Specifically, the low-frequency stabilization network 200 suppresses low-frequency oscillations, the mid-frequency stabilization network 300 suppresses mid-frequency oscillations, and the high-frequency stabilization network 400 suppresses high-frequency oscillations. This results in a stability factor μ greater than 1 across the entire frequency band for the RF amplifier circuit, with a flat gain within the target band and automatic gain roll-off outside the target band. In this disclosure, the coordinated frequency responses of the low-frequency stabilization network 200, the mid-frequency stabilization network 300, and the high-frequency stabilization network 400 create strong feedback outside the entire frequency band to efficiently suppress oscillations, and weak feedback within the entire frequency band to preserve gain. As will be seen from the following description, compared to the case without the low-frequency stabilization network 200, the mid-frequency stabilization network 300, and the high-frequency stabilization network 400, the gain loss of the RF amplifier circuit of this disclosure does not exceed 2 dB.

[0061] like Figure 4 As shown, the RF amplifier circuit of this embodiment also includes a gate bias network 600. The gate bias network 600 is connected between the base B of the bipolar junction transistor 120 and the bias voltage terminal. The gate bias network 600 is used to provide a DC operating voltage to the base B of the bipolar junction transistor 120. The gate bias network 600 may include a gate bias resistor 610 and a gate bias inductor 620. The gate bias resistor 610 and the gate bias inductor 620 are connected in series to form the gate bias network 600. One end of the gate bias resistor 610 is connected to the bias voltage terminal, and the other end of the gate bias resistor 610 is connected to one end of the gate bias inductor 620, the other end of the gate bias inductor 620 being connected to the base B of the bipolar junction transistor 120. In this disclosure, the bias voltage terminal is used to input the bias voltage Vbias, and the RF signal input terminal RFI is used to input the RF signal.

[0062] like Figure 4As shown, the RF amplifier circuit of this embodiment also includes a drain bias network 700. The drain bias network 700 is connected between the collector C of the bipolar junction transistor 120 and the power supply voltage terminal. The drain bias network 700 is used to provide a DC operating voltage VDD to the collector C of the bipolar junction transistor 120. The drain bias network 700 may include a drain bias resistor 710 and a drain bias inductor 720. The drain bias resistor 710 and the drain bias inductor 720 are connected in series to form the drain bias network 700. One end of the drain bias resistor 710 is connected to the power supply voltage terminal, and the other end of the drain bias resistor 710 is connected to one end of the drain bias inductor 720, the other end of the drain bias inductor 720 being connected to the collector C of the bipolar junction transistor 120. In this disclosure, the power supply voltage terminal is used to provide the DC operating voltage VDD.

[0063] Furthermore, the RF amplifier circuit of this embodiment also includes an input DC blocking capacitor 510 and an output DC blocking capacitor 520. The input DC blocking capacitor 510 is disposed between the RF signal input terminal RFI and the base B of the bipolar junction transistor 120, allowing the RF signal to pass through while also isolating the gate bias voltage terminal from the RF signal input terminal. The output DC blocking capacitor 520 is disposed between the collector C of the bipolar junction transistor 120 and the RF signal output terminal RFO. The output DC blocking capacitor 520 allows the RF signal to pass through and be delivered to the RF signal output terminal RFO, while completely blocking the leakage of the DC operating voltage VDD of the transistor collector to the RF signal output terminal RFO.

[0064] In this disclosure, by designing the synergistic parameter relationships of the low-frequency, mid-frequency, and high-frequency stabilization networks, the stability factor μ of the broadband RF amplifier circuit is made greater than 1 across the entire frequency band. Thus, according to the technical solution of this disclosure, the synergistic design of the stabilization networks of the broadband RF amplifier circuit can be achieved, thereby ensuring that the gain loss is controlled within a preset range while maintaining a stability factor μ greater than 1 across the entire frequency band, thereby significantly improving design efficiency and predictability. In this application, the aforementioned synergistic parameter relationships are achieved by designing the parameters of the components included in the low-frequency, mid-frequency, and high-frequency stabilization networks.

[0065] Low-frequency, mid-frequency, and high-frequency stabilization networks can include corresponding components according to design requirements, and the function of each stabilization network can be adjusted by adjusting the parameters of these components. The following detailed description is based on specific example components provided in this disclosure; however, those skilled in the art should understand that even when different components are included in each stabilization network, the component parameters of each stabilization network can still be designed according to the design concept of this disclosure. In the design process of the component parameters of each stabilization network, the initial stability factor μ of the RF amplifier circuit excluding the low-frequency, mid-frequency, and high-frequency stabilization networks in each frequency band is determined. The gap between the initial stability factor μ and the stability threshold of the stability factor μ in each frequency band is determined. The target contribution of each stabilization network to the stability factor μ is determined based on the size or proportion of the gap in each frequency band. The component parameters of each stabilization network are designed based on the target contribution of each stabilization network, thereby achieving a synergistic parameter relationship.

[0066] Without incorporating low-frequency, mid-frequency, and high-frequency stabilization networks into the RF amplifier circuit, the initial stability factors μ of the RF amplifier circuit in the low-frequency, mid-frequency, and high-frequency bands are obtained. The difference (gap) between the initial stability factor μ and the stability threshold of the stability factor μ in each frequency band is calculated. This yields the gap ΔμL for the low-frequency band, ΔμM for the mid-frequency band, and ΔμH for the high-frequency band. The target contribution of the three stabilization networks can be determined based on the ratio of ΔμL, ΔμM, and ΔμH (e.g., by assigning coefficients to the target contribution), or the target contribution can be determined based on the magnitude relationship between ΔμL, ΔμM, and ΔμH.

[0067] The size of the gap is directly proportional to the target contribution. The larger the gap, the greater the target contribution; the smaller the gap, the smaller the target contribution. For example, if the gap ΔμM in the mid-frequency band is determined to be the largest, followed by the gap ΔμH in the high-frequency band, and the gap ΔμL in the low-frequency band the smallest, then the mid-frequency band stabilization network will undertake the main compensation, the high-frequency band stabilization network will undertake secondary compensation, and the low-frequency band stabilization network will undertake slight compensation. Through the coordinated compensation of these three networks, the broadband RF amplifier circuit achieves a stability factor μ greater than 1 across the entire band, a flat gain across the entire target band, and a gain roll-off outside the target band, while ensuring that the gain loss of the broadband RF amplifier circuit does not exceed 2dB.

[0068] exist Figure 5The diagram shows that, without the addition of low-frequency, mid-frequency, and high-frequency stabilization networks to the RF amplifier circuit, the stability factor μ ≈ 0.65 for the low-frequency band, μ ≈ 0.35 for the mid-frequency band (with the center frequency set at 2.5 GHz), and μ ≈ 0.55 for the high-frequency band (at 5 GHz). The gaps (differences) between the low-frequency gap ΔμL, the mid-frequency gap ΔμM, and the high-frequency gap ΔμH and the stability threshold of the stability factor μ (as an example, the stability threshold of the stability factor μ can be set to 1) are ΔμL ≈ 0.35, ΔμM ≈ 0.65, and ΔμH ≈ 0.45, respectively, with a gap ratio of ΔμL : ΔμM : ΔμH = 7 : 13 : 9. Based on these gap ratios, a quantitative collaborative design of the three stabilization networks can be performed. The mid-frequency band has the largest gap (ΔμM≈0.65), therefore the mid-frequency stabilization network is responsible for the main compensation, with a target contribution of ≥0.35. The high-frequency band has the second largest gap (ΔμH≈0.45), and the high-frequency stabilization network is responsible for secondary compensation, with a target contribution of ≥0.25. The low-frequency band has the smallest gap (ΔμL≈0.35), and the low-frequency stabilization network is responsible for slight compensation, with a target contribution of ≥0.15. Thus, the sum of the stabilization contributions of the three stabilization networks, Δμ_total, is ≥0.75. Combined with the synergistic effect of the three stabilization networks in each frequency band, this collectively raises the overall stability factor μ to above 1.0. Simulation results show that after adding three stabilization networks, the stabilization factor μ in the low-frequency band increases from 0.65 to 1.17, the stabilization factor μ in the mid-frequency band increases from 0.35 to 1.08, and the stabilization factor μ in the high-frequency band increases from 0.55 to 1.17. Therefore, the stability condition μ>1 is met across the entire band, and the stabilization factor μ in the mid-frequency band is improved from 0.35 to approximately 1.1, while the gain loss is controlled within an acceptable range.

[0069] exist Figure 6 The diagram shows the test results after adding a mid-frequency stabilization network to the RF amplifier circuit, without prior additions to low-frequency, mid-frequency, and high-frequency stabilization networks. The component parameters of the mid-frequency stabilization network were determined based on the target contribution. Figure 6 As shown, the stability factor μ in the mid-frequency band is increased to 0.7 (2.5 GHz). Then, a low-frequency band stabilization network is added, and similarly, the component parameters of the low-frequency band stabilization network are determined based on the target contribution. Figure 7 The results show the test results of adding a low-frequency stabilization network, where the mid-frequency stability factor μ increases to 0.85 (2.5 GHz), and the low-frequency band is already in a stable state (e.g., 0.5 GHz). Finally, a high-frequency stabilization network is added, and similarly, the component parameters of the high-frequency stabilization network are determined based on the target contribution. At this point, the three stabilization networks work synergistically. Figure 8The results show the test results of adding a high-frequency band stabilization network, in which the stability factor μ in the mid-frequency band is increased to 1.08 (2.5 GHz), and full stabilization is achieved in the target band.

[0070] exist Figure 9 It shows Figure 8 The corresponding gain curve of the RF amplifier circuit. The stability factor μ and the gain dB(S(2,1)) curve show opposite trends. From Figure 8 and Figure 9 In this design, an RF amplifier circuit based on the above-mentioned specifications was added. This circuit satisfies the stability condition of a stability factor μ greater than 1 across the entire frequency band, while achieving a gain of 17 dB in the passband (at m3 with a center frequency (freq) of 2.5 GHz). This is in contrast to the unstable state without any stabilization network (gain of approximately 18.5 dB). Figure 9 The gain loss of this embodiment is only 1.5dB, and its 3dB bandwidth is approximately 2.9GHz, with a significant out-of-band gain roll-off. Therefore, the test results of this embodiment verify that this disclosure achieves full-band stability while obtaining narrowband high-gain characteristics with minimal gain loss, making it suitable for communication scenarios with high gain requirements and relatively limited bandwidth needs. In the design of RF amplifier circuits, 3dB is typically used as the criterion for determining the effective operating bandwidth; the frequency range within which the peak gain drops by less than 3dB is considered the flat effective operating region. Figure 9 As shown, the frequency range is approximately from 1.2 GHz to 4 GHz, indicating that the RF amplifier circuit of this disclosure has bandpass gain characteristics, that is, it maintains a flat gain within this frequency range and achieves roll-off outside this frequency range.

[0071] Compared to traditional stabilization methods (such as those using only gate / base series resistors or simple parallel RC networks), which suffer from excessive gain loss (typically 3-6 dB), limited frequency band compensation, and difficulty in simultaneously achieving full-band stability and in-band gain maintenance, this disclosure's main innovation lies in proposing a frequency-band partitioned and quantized collaborative three-network stabilization architecture. Through the division of labor and cooperation among low-frequency, mid-frequency, and high-frequency stabilization networks, and by quantifying the stability contribution of each network based on the stability factor gap in each frequency band, absolute stability with μ>1 is achieved across the entire band. According to the technical solution of this disclosure, the gain loss is extremely small, with actual measurements showing only 1.5 dB, far lower than the 3-6 dB of traditional methods. Through collaborative fine-tuning, flexible switching between high-gain narrow-bandwidth and low-gain high-bandwidth operating modes can be achieved within the same circuit topology. The stabilization network is transformed from a performance loss mechanism in the traditional sense into an active tool for gain shaping, simultaneously achieving full-band stability and bandpass gain characteristics. This provides a low-cost, highly reusable innovative technical path for high-performance design of broadband RF amplifier circuits.

[0072] The following will be based on Figure 3 and Figure 4 The circuit topology of the embodiment is used as an example to describe in detail the above-mentioned flexible switching technical effect. For the same circuit topology, it is possible to flexibly switch between two operating modes: high gain and narrow bandwidth, and low gain and high bandwidth. The same circuit topology described here refers to a circuit formed by the same components, but the parameters of the components can be changed according to the actual situation, such as resistance value, capacitance value, transmission line size, etc.

[0073] exist Figure 3 and Figure 4 In the embodiments, the mid-frequency stabilization network is designed such that: when the length of the first transmission line decreases, the gain of the mid-frequency band is reduced and the bandwidth is widened; when the length of the first transmission line increases, the gain of the mid-frequency band is increased and the bandwidth is narrowed. The low-frequency stabilization network is designed such that: when the first resistor and the first capacitor decrease, the gain of the low-frequency band is increased; when the first resistor and the first capacitor increase, the gain of the low-frequency band is decreased. The high-frequency stabilization network is designed such that: when the second capacitor decreases and the second resistor increases, the gain of the high-frequency band is increased; when the second capacitor increases and the second resistor decreases, the gain of the high-frequency band is decreased.

[0074] As an example, switching from a high-gain, narrow-bandwidth mode to a low-gain, high-bandwidth mode only requires adjusting the component parameters of the same circuit topology. In this case, the main adjustment trends are: appropriately reducing the first resistor and first capacitor (low-frequency stabilization network) to reduce insertion loss at the low-frequency end, thereby increasing gain in the low-frequency band; moderately shortening the length of the first transmission line (intermediate-frequency stabilization network) and adjusting the impedance characteristics of the negative feedback network to enhance the effective feedback depth, reduce intermediate-frequency gain, and widen the bandwidth; simultaneously reducing the second capacitor and increasing the second resistor (high-frequency stabilization network) to present high impedance to high-frequency signals, thereby reducing shunt loss at the high-frequency end and appropriately increasing high-frequency gain. The essence of these adjustments is to release more gain resources to the high-frequency and low-frequency regions while ensuring full-band stability (μ>1), thereby expanding the passband width and achieving a smooth switch from "high-gain, narrow-bandwidth" to "low-gain, high-bandwidth." This allows for flexible adaptation to the different gain and bandwidth requirements of various communication scenarios using the same circuit topology.

[0075] According to a further embodiment of this disclosure, a design method for the above-described broadband radio frequency amplifier circuit is also provided. Figure 10A flowchart of the design method is shown, including steps S1010 to S1040. In step S1010, without excluding low-frequency, mid-frequency, and high-frequency stabilization networks in the broadband RF amplifier circuit, the initial stabilization factor μ for each frequency band in the low-frequency, mid-frequency, and high-frequency bands is determined. In step S1020, the gap between the initial stabilization factor μ for each frequency band and the stabilization threshold of the stabilization factor μ is determined. In step S1030, the target contribution of each stabilization network to the stabilization factor μ is determined based on the size or proportion of the gap for each frequency band. In step S1040, the component parameters of each stabilization network are designed based on the target contribution of each stabilization network to the stabilization factor μ. Furthermore, the specific details of this design method can be further referred to the description above; for the sake of brevity, they will not be repeated here.

[0076] According to the RF amplifier circuit disclosed herein, the problem of traditional single-band stabilization networks being unable to balance stability, gain, and frequency response is fundamentally solved through the synergistic effect of low-frequency band stabilization networks, mid-frequency band stabilization networks, and high-frequency band stabilization networks. Its technical effects are reflected in the following three aspects.

[0077] Firstly, the low-frequency stabilization network mainly suppresses oscillations in the low and mid-frequency bands across the entire band. The mid-frequency stabilization network introduces negative feedback in the mid-frequency band to suppress the instability trend in the mid-frequency band. The high-frequency stabilization network specifically absorbs parasitic energy in the high-frequency band to suppress oscillations in the high-frequency band. The three stabilization networks act on different frequency bands respectively, working together to ensure that the stability factor μ of the RF amplifier circuit is greater than 1 across the entire band, thus achieving unconditional stability across the entire band.

[0078] Secondly, by coordinating the frequency responses of the low-frequency, mid-frequency, and high-frequency stabilization networks, strong feedback is formed across the entire frequency band to effectively suppress oscillations, while weak feedback is formed within the entire frequency band to preserve gain. This achieves absolute stability across the entire frequency band while keeping gain loss at a low level. As the test results above show, compared to the case without the three stabilization networks, the gain loss of the RF amplifier circuit disclosed in this invention is only about 1.5dB, significantly lower than the 3dB to 6dB or more gain loss typically caused by traditional stabilization methods, effectively achieving a balance between stability and high gain.

[0079] Thirdly, through the frequency selectivity of the low-frequency, mid-frequency, and high-frequency stabilization networks, these three networks not only suppress oscillations but also actively participate in adjusting the gain frequency characteristics of the RF amplifier circuit. This ensures that the gain remains flat throughout the target band and spontaneously rolls off outside the target band. Therefore, the RF amplifier circuit of this disclosure directly achieves bandpass gain response characteristics without the need for additional filters, transforming the stabilization networks, originally used only to consume gain and prevent oscillations, into functional components that achieve both frequency selection and gain curve shaping.

[0080] The following describes several application scenarios of the radio frequency amplifier circuit according to the present disclosure in order to illustrate the application of the radio frequency amplifier circuit of the present disclosure.

[0081] In high-frequency wireless communications in the 5G or Sub-6 GHz bands, such as cellular vehicle-to-everything (C-V2X) communication or Wi-Fi 6 / 7 routers operating in the 5.9 GHz band, the RF front-end module requires extremely high anti-interference capabilities and signal integrity. The RF amplifier circuit disclosed herein can be directly used as a broadband low-noise amplifier in the receiver front-end for this band. Utilizing the bandpass gain characteristics brought about by its stable network across the entire band, this circuit can provide flat gain within the target band. Simultaneously, by leveraging the spontaneous gain roll-off characteristic outside the operating frequency band, it effectively filters out strong interference signals from adjacent frequency bands, significantly improving the linearity and anti-blocking capability of the receiving link.

[0082] In novel carbon-based radio frequency integrated circuits, the radio frequency amplifier circuit disclosed herein, through the synergistic design of low-frequency, mid-frequency, and high-frequency stabilization networks, can effectively suppress potential oscillations of such novel high-frequency devices across the entire operating frequency band, achieving unconditional stability across the entire band. Furthermore, each stabilization network in this circuit is a purely passive structure, compatible with standard large-scale semiconductor manufacturing processes, making it highly suitable for the large-scale production and layout verification of monolithic microwave integrated circuits on industrial-grade wafer fabrication lines.

[0083] In ultra-wideband radar systems (such as vehicle-mounted collision avoidance radar and through-wall radar), RF amplifiers need to cover an extremely wide operating frequency band and must maintain absolute stability in complex electromagnetic environments. The RF amplifier circuit disclosed herein maintains a stability factor μ greater than 1 across the target band, meeting the stringent requirements of ultra-wideband radar systems for absolute stability of the RF front-end across the entire band. Applying the RF amplifier circuit of this disclosure to the receiving link can effectively avoid the risk of oscillations introduced by sudden strong signals or impedance mismatches, preventing the RF link from becoming blind or failing in real-world environments.

[0084] In multi-stage cascaded RF power amplifier architectures, the driver stage amplifier not only needs to provide sufficient linear drive power but also must prevent signal reflections from subsequent high-power amplifiers from causing self-oscillation in the preceding stage. The RF amplifier circuit disclosed herein utilizes its multi-branch cooperative degradation structure, which includes low-frequency, mid-frequency, and high-frequency stabilization networks, to provide excellent input / output impedance matching and reverse isolation characteristics. Using this RF amplifier circuit as the driver amplification module in the transmit link can effectively suppress oscillations caused by load pulling effects while ensuring gain flatness and full-band stability, thus improving the robustness of the entire transmit link.

[0085] It should be understood that the above application embodiments are merely several exemplary applications of the RF amplifier circuit of this disclosure and are not intended to limit the scope of protection of this disclosure. Based on the full-band stability and bandpass gain characteristics of the circuit disclosed herein, it can also be widely applied to other RF front-end scenarios requiring broadband absolute stability and out-of-band rejection capabilities.

[0086] Those skilled in the art should understand that the above embodiments are merely for illustrating the present disclosure and are not intended to limit the scope of the disclosure. Those skilled in the art can make other changes or modifications based on the above disclosure, and these changes or modifications still fall within the scope of the present disclosure.

Claims

1. A wideband radio frequency amplifier circuit having full-band stability characteristics, characterized by, include: A transistor, wherein the transistor is a bipolar junction transistor or a field-effect transistor; A low-frequency stabilization network is connected between the base of the bipolar junction transistor or the gate of the field-effect transistor and a reference ground to suppress low-frequency oscillations across the entire frequency band. A mid-frequency stabilization network, connected between the emitter of the bipolar junction transistor or the source of the field-effect transistor and a reference ground, is used to suppress mid-frequency oscillations across the entire frequency band; and A high-frequency stabilization network, connected between the collector of the bipolar junction transistor or the drain of the field-effect transistor and a reference ground, is used to suppress high-frequency oscillations across the entire frequency band. Specifically, by designing the synergistic effect parameter relationship between the low-frequency band stabilization network, the mid-frequency band stabilization network, and the high-frequency band stabilization network, the stability factor μ of the broadband RF amplifier circuit is made greater than 1 across the entire frequency band. The synergistic effect parameter relationship is determined as follows: the initial stability factor μ of the RF amplifier circuit excluding the low-frequency band stabilization network, the mid-frequency band stabilization network, and the high-frequency band stabilization network is determined for each frequency band; the gap between the initial stability factor μ and the stability threshold of the stability factor μ for each frequency band is determined; the target contribution of each stabilization network to the stability factor μ is determined based on the size or proportion of the gap for each frequency band; and the component parameters of each stabilization network are designed based on the target contribution of each stabilization network, thereby realizing the synergistic effect parameter relationship.

2. The wideband radio frequency amplifier circuit of claim 1, wherein, The size of the gap is directly proportional to the target contribution.

3. The wideband radio frequency amplifier circuit of claim 1, wherein, Compared to the case where the low-frequency band stabilization network, mid-frequency band stabilization network, and high-frequency band stabilization network are not set, the gain loss of the broadband RF amplifier circuit does not exceed 2dB.

4. The wideband radio frequency amplifier circuit of any of claims 1 to 3, wherein, The mid-frequency stabilization network includes a first transmission line connected between the emitter of the bipolar junction transistor or the source of the field-effect transistor and a reference ground, for introducing negative feedback at the emitter of the bipolar junction transistor or the source of the field-effect transistor to suppress oscillations in the mid-frequency band.

5. The broadband radio frequency amplifier circuit as described in claim 4, characterized in that, The mid-frequency stable network is designed such that when the length of the first transmission line decreases, the gain of the mid-frequency band is reduced and the bandwidth is widened; when the length of the first transmission line increases, the gain of the mid-frequency band is increased and the bandwidth is narrowed.

6. The broadband radio frequency amplifier circuit according to any one of claims 1 to 3, characterized in that, The low-frequency stabilization network includes a first resistor and a first capacitor connected in series.

7. The broadband radio frequency amplifier circuit as described in claim 6, characterized in that, The low-frequency stabilization network is designed such that when the first resistor and the first capacitor decrease, the gain of the low-frequency band is increased, and when the first resistor and the first capacitor increase, the gain of the low-frequency band is decreased.

8. The broadband radio frequency amplifier circuit as described in any one of claims 1 to 3, characterized in that, The high-frequency stabilization network includes a second resistor, a second capacitor, and a second transmission line, wherein the second resistor and the second capacitor are connected in parallel to form a parallel circuit, and the parallel circuit is connected in series with the second transmission line.

9. The broadband radio frequency amplifier circuit as described in claim 8, characterized in that, The high-frequency stabilization network is designed such that when the second capacitor decreases and the second resistor increases, the gain of the high-frequency band is increased, and when the second capacitor increases and the second resistor decreases, the gain of the high-frequency band is decreased.

10. A design method for a broadband radio frequency amplifier circuit as described in any one of claims 1 to 9, characterized in that, include: In the absence of the low-frequency band stabilization network, the mid-frequency band stabilization network, and the high-frequency band stabilization network in the broadband RF amplifier circuit, the initial stability factor μ for each frequency band in the low-frequency band, mid-frequency band, and high-frequency band is determined; Determine the gap between the initial stability factor μ and the stability threshold of the stability factor μ for each frequency band; The target contribution of each stabilization network to the stabilization factor μ is determined based on the size or proportion of the gap in each frequency band; and Based on the target contribution of each stabilizing network to the stabilizing factor μ, the component parameters of each stabilizing network are designed.

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