Broadband High-Efficiency Filtered Power Amplifier and Its Output Matching Network Design Method

Abstract

This invention provides a broadband high-efficiency filtered power amplifier and its output matching network design method, belonging to the field of wireless communication technology. It includes a power amplifier body and an output matching network connected to its output terminal. The output matching network structure is based on a three-mode lateral coupling filter. The output matching network comprises multiple directly connected transmission lines, forming a first sub-network, a second sub-network, a third sub-network, and a fourth sub-network. The structures of the first and second sub-networks are configured to be equivalent to λ / 4 transmission lines with harmonic impedance control. By adopting the output matching network structure, fundamental frequency matching, harmonic control, and filtering functions are integrated: a fundamental frequency matching with steep edges is achieved using a three-mode lateral resonator, employing an equivalent T-shaped... l The 4-wire control extends the second harmonic impedance to the high-efficiency region, achieving wide bandwidth operation while maintaining high efficiency and excellent harmonic suppression capabilities.

Description

Technical Field

[0001] This invention belongs to the field of wireless communication technology, specifically a design method for a broadband high-efficiency filtered power amplifier and its output matching network. Background Technology

[0002] The development of broadband filtered power amplifier technology in the field of radio frequency power amplifiers stems from the urgent need for multi-band, wide bandwidth and high data rate in 5G wireless communication.

[0003] Power amplifier devices need to operate in the nonlinear region to generate rich harmonics, and the industry commonly uses continuous class F / class-inverse class F and class J harmonic control techniques. However, when power amplifiers are cascaded with filters, mismatch and insertion loss between modules can lead to a deterioration in the overall system efficiency. Existing filter power amplifier design techniques have significant shortcomings: designs using high-performance resonant structures can improve efficiency but are limited in bandwidth; microwave filter converter-based schemes, while possessing harmonic suppression capabilities, are still limited by narrow bandwidth, and the coupling structure introduces radiation losses and is difficult to tune precisely; while designs focusing on in-band matched filtering suffer from low drain efficiency due to neglecting harmonic impedance control.

[0004] In summary, traditional broadband power amplifiers face a core contradiction: it is difficult to balance efficiency and bandwidth, and the harmonics they generate are difficult to suppress over a wide frequency band. Summary of the Invention

[0005] To address the shortcomings of the prior art, the technical problem to be solved by the embodiments of the present invention is to provide a broadband high-efficiency filtered power amplifier and its output matching network design method.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] A broadband high-efficiency filtered power amplifier includes a power amplifier body and an output matching network connected to its output terminal;

[0008] The output matching network is a broadband filter impedance converter, whose structure is based on a three-mode transversely coupled filter, which can achieve fundamental impedance matching in the passband and provide suppression characteristics at harmonic frequencies.

[0009] The output matching network comprises multiple directly connected transmission lines, forming a first subnetwork, a second subnetwork, a third subnetwork, and a fourth subnetwork;

[0010] The first and second sub-networks are configured to be equivalent to λ / 4 transmission lines with harmonic impedance control, used to adjust the position of harmonic impedance on the Smith chart.

[0011] As a further improvement: the first sub-network and the second sub-network each include three transmission lines, and the third sub-network and the fourth sub-network each include one transmission line;

[0012] The characteristic impedance and electrical length of each transmission line are determined by the coupling matrix synthesis method so that the output matching network simultaneously meets the preset in-band matching, harmonic suppression and bandwidth specifications.

[0013] As a further improvement: the three resonant modes of the output matching network are not directly coupled and together constitute the passband of a three-mode bandpass filter.

[0014] This invention also provides a method for designing the output matching network of a broadband high-efficiency filtered power amplifier, characterized by comprising:

[0015] Determine the design specifications of the filter power amplifier, including center frequency, bandwidth, in-band return loss, and target fundamental impedance;

[0016] Based on the theory of transversely coupled filters, the coupling matrix is ​​synthesized, and the resonant frequency and external quality factor required for the output matching network are calculated according to the coupling matrix.

[0017] The resonant modes are mapped to the resonant conditions of a three-mode transverse filter, and the susceptance slope parameters of each mode are calculated.

[0018] By using an equivalent circuit model, the filter structure is transformed into a matching network composed of multiple transmission lines, and the characteristic impedance and electrical length of each transmission line segment are determined.

[0019] As a further improvement: in the step of converting the filter structure into a matching network composed of multiple transmission line segments using an equivalent circuit model, and determining the characteristic impedance and electrical length of each transmission line segment:

[0020] By combining the ABCD matrices of the T-type line and the λ / 4 transmission line, the equivalent design equation is obtained. Based on the equivalent design equation, the characteristic impedance and electrical length of each segment of the transmission line are determined.

[0021] As a further improvement, the output matching network is implemented using a microstrip or stripline structure.

[0022] As a further improvement: calculate the required resonant frequency and external quality factor of the output matching network based on the coupling matrix.

[0023] ;

[0024] ;

[0025] in, f 0iThe resonant frequency, QE i External quality factor M Si , M ii For elements of the coupling matrix, f 0 represents the center frequency, and FBW represents the bandwidth.

[0026] Compared with existing technologies, the advantages of this invention are: by adopting an innovative output matching network structure, fundamental frequency matching, harmonic control, and filtering functions are integrated into one; a three-mode transverse resonator is used to achieve fundamental frequency matching with steep edges, while an equivalent T-shaped resonator is employed. λ The 4-wire control brings the second harmonic impedance to the high-efficiency region, achieving wide bandwidth operation while maintaining high efficiency and excellent harmonic suppression capabilities, thus effectively overcoming the contradiction between bandwidth and efficiency in existing technologies. Attached Figure Description

[0027] Figure 1 Circuit diagram of a broadband high-efficiency filtered power amplifier;

[0028] Figure 2 A simplified circuit diagram of the output matching network for a broadband high-efficiency filtered power amplifier;

[0029] Figure 3 This is a diagram of the lateral coupling topology of a broadband high-efficiency filtered power amplifier.

[0030] Figure 4 A flowchart illustrating the design of a third-order transverse filter for a broadband high-efficiency filtering power amplifier;

[0031] Figure 5 The filter response curves of each parallel LC resonator of the broadband high-efficiency filter power amplifier are shown.

[0032] Figure 6 The filter response curve of the cross-shaped filter for a broadband high-efficiency filtering power amplifier;

[0033] Figure 7 For broadband high-efficiency filtered power amplifiers Z S Simulation of a 15Ω filter impedance converter S Parameter curves;

[0034] Figure 8 The impedance trajectories corresponding to the fundamental and second harmonics of the 15-50Ω filter impedance converter for a broadband high-efficiency filter power amplifier.

[0035] Figure 9 15-50Ω filter impedance converter for broadband high-efficiency filter power amplifiers in different θ t Simulation under certain conditions | S 21 |Graph;

[0036] Figure 10 Different electrical lengths for broadband high-efficiency filtered power amplifiers θ t The trajectory of the second harmonic corresponding to the time in the Smith chart, as shown in Figure (a). θ t It is 25°, in Figure (b) θ t It is 35°, in Figure (c) θ t It is 43°, in Figure (d) θ t It is 55°;

[0037] Figure 11 This is a topology diagram of a broadband high-efficiency filtered power amplifier.

[0038] Figure 12 Schematic diagram of the input matching network for a broadband high-efficiency filtered power amplifier;

[0039] Figure 13 The input matching impedance trajectory diagram for a broadband high-efficiency filtered power amplifier;

[0040] Figure 14 S-parameter curves of a 15-50Ω filter impedance converter for a broadband high-efficiency filter power amplifier (simulated).

[0041] Figure 15 The fundamental impedance and second harmonic impedance trajectories of a broadband high-efficiency filtered power amplifier are shown.

[0042] Figure 16 This is a layout dimension diagram of a broadband high-efficiency filtered power amplifier.

[0043] Figure 17 Small-signal performance graph of a broadband high-efficiency filtered power amplifier tested;

[0044] Figure 18 The large-signal simulation and test results of the output power, power gain, and drain efficiency of the broadband high-efficiency filtered power amplifier as a function of frequency are shown in the figure. Detailed Implementation

[0045] The technical solution of this application will be further described in detail below with reference to specific embodiments.

[0046] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0047] Please see Figure 1 to Figure 3 In one embodiment, a broadband high-efficiency filtered power amplifier includes a power amplifier body and an output matching network connected to its output.

[0048] The output matching network is a broadband filter impedance converter, whose structure is based on a three-mode transversely coupled filter, which can achieve fundamental impedance matching in the passband and provide suppression characteristics at harmonic frequencies.

[0049] The output matching network comprises multiple directly connected transmission lines, forming a first subnetwork, a second subnetwork, a third subnetwork, and a fourth subnetwork;

[0050] The first and second sub-networks are configured to be equivalent to λ / 4 transmission lines with harmonic impedance control, used to adjust the position of harmonic impedance on the Smith chart.

[0051] In this embodiment, Figure 1 The designed output matching network consists of four subnetworks: a first subnetwork, a second subnetwork, a third subnetwork, and a fourth subnetwork. The first subnetwork contains three transmission lines (two...). Z c1 and Z t1 ), the electric lengths are respectively θ c1 and θ t1 The second subnetwork contains three transmission lines (two of which are...). Z c2 and Z t2 ), the electric lengths are respectively θ c2 and θ t2 The third subnetwork contains transmission lines. Z s1 Its electric length is θ s1 The fourth subnetwork contains transmission lines. Z s2 Its electric length is θ s2 The connecting lines in the diagram define the electrical connection topology between the transmission lines.

[0052] With proper design, the first or second subnetwork can be equivalent to a network with harmonic impedance control functionality. λ / 4 transmission line, and the position of harmonic impedance on the Smith chart is adjusted by controlling its impedance and electrical length values. For ease of understanding, Figure 2 A simplified circuit of the proposed output matching network is shown. This includes the input impedance. Z s, output impedance Z L And four transmission lines, the impedance values ​​of the four transmission lines are respectively Z 1- Z 4. Electrical length is θ 1- θ 4. The connecting lines in the diagram define the electrical connection topology between the transmission lines. From the perspective of filter theory and multimode resonator theory, it consists of three independent resonant modes ( f even1(2) , f odd The three modes together constitute the passband of the three-mode bandpass filter. Since there is no coupling between these three modes, its topology corresponds to a laterally coupled topology, as shown in the diagram. Figure 3 As shown. Here, S and L represent port 1 and port 2 respectively, and the yellow circles marked 1-3 represent the three resonant modes. M Si and M Li These represent the interactions between the source, load, and resonator, respectively, and the lines in the diagram represent the coupling relationships between the components. Based on the topology, Figure 2 The filter matching circuit can be designed based on the theory of transverse filters.

[0053] Please see Figure 1 to Figure 6 The present invention also provides a method for designing the output matching network of a broadband high-efficiency filtered power amplifier, comprising:

[0054] Determine the design specifications of the filter power amplifier, including center frequency, bandwidth, in-band return loss, and target fundamental impedance TZ. S ;

[0055] Based on the theory of transversely coupled filters, the coupling matrix is ​​synthesized, and the resonant frequency and external quality factor required for the output matching network are calculated according to the coupling matrix.

[0056] The resonant modes are mapped to the resonant conditions of a three-mode transverse filter, and the susceptance slope parameters of each mode are calculated.

[0057] By using an equivalent circuit model, the filter structure is transformed into a matching network composed of multiple transmission lines, and the characteristic impedance and electrical length of each transmission line segment are determined.

[0058] In this embodiment, the setting parameters for the three-mode transverse filter with Chebyshev response are: center frequency. f 0 = 3.5 GHz, bandwidth FBW = 28.5%, in-band return loss RL ≥ 20 dB, and two transmission zeros are located at 2.7 and 4.3 GHz.

[0059] According to design specifications, coupling matrix elements M Si , M ii and M Li ( i =1-3) can be determined as: M S1 = M L1 =0.404, M S2 =- M L2 =0.935, M S3 = M L3 =-0.348. The coupling matrix is:

[0060] ;

[0061] Calculate the required resonant frequency and external quality factor for the output matching network based on the coupling matrix:

[0062] ;

[0063] ;

[0064] in, f 0i The resonant frequency, QE i External quality factor M Si , M ii For elements of the coupling matrix, f 0 represents the center frequency, and FBW represents the bandwidth.

[0065] The resonant frequency can be calculated from the above formula. f 01 =2.88GH Z , f 02 =3.56GH Z and f 03 =4.21GH Z， The coupling between the source and the load is calculated as an external quality factor. QE 1 = 20.19 QE 2 = 5.47 and QE 3 = 25.94.

[0066] The design concept of a transverse filter can be applied to the comprehensive design of this three-mode filter, whose three resonant frequencies are respectively f even1 = f 01 , f odd = f 02 and f even2 = f 03 The resonance conditions for each mode are summarized as follows:

[0067] ;

[0068] .

[0069] Slope of cross-shaped filter b even1 , b odd and b even2 The calculation formula is:

[0070] ;

[0071] , i=1,2;

[0072] pass QE i / Z S ( i =1-3) Calculate the theoretical susceptance slope b even1 , b odd and b even2 The values ​​are 0.43, 0.08, and 0.59, respectively. Finally, by solving the equations and combining the equations, the impedance parameters calculated in Matlab software are: Z 1= Z 2 = 19.62Ω, Z 3 = 33.8Ω Z 4 = 48.6Ω, the electrical length at a frequency of 3.5GHz. θ 1= θ 2 = 88.9° θ 3 = 112.6° and θ4 = 72.9°.

[0073] The above calculation process provides a parameterization method for designable filter matching networks based on coupling matrix synthesis. This method takes system circuit specifications as input and transmission line physical dimensions as output, establishing a complete synthesis design flow. Its ultimate goal is to accurately realize a tri-mode filter that combines good matching, harmonic suppression, and out-of-band selectivity. This structure, as the output matching network of a power amplifier, has key application value in the design of high-efficiency RF power amplifiers. Its value lies primarily in simultaneously solving the core issues of power amplifier device efficiency and bandwidth through integrated design.

[0074] Besides achieving filtering characteristics, the above structure, serving as the output matching network of the power amplifier, also needs to match the fundamental impedance and second harmonic impedance within the bandwidth to appropriate positions. Through load-driven simulation, the power amplifier's position at the center frequency is determined. f The optimal fundamental impedance at 0 is (15 + j2.5) Ω, whose imaginary part is very small and negligible. Generally, the imaginary part can be eliminated by adding a stub after the amplifier in the design. The goal of narrowband matching is to transform the complex impedance to a target impedance (e.g., 50 Ω) through a matching network at a single frequency point. The goal of wideband matching is to transform the complex impedance to a small region close to the target impedance within a frequency range through a matching network. The essence of achieving wideband complex matching is to design a matching network whose frequency response can compensate for the variation of the transistor's output impedance with frequency.

[0075] The output matching network is implemented using a microstrip line or stripline structure.

[0076] Implementing impedance transformation in a filter is relatively simple; it involves redesigning the input and output coupling coefficients based on the required impedance. For this structure, the impedance... Z 1 and Z 2 needs to be reduced. Z 3, Z 4, θ 3 and θ 4 remains unchanged to satisfy the in-band matching condition of 15Ω termination impedance and RL=20dB. Figure 7 The designed satisfaction was demonstrated. Z The simulated S-parameters of the converter with a 15Ω filter impedance show that the return loss is better than 20dB within the specified range, meeting the predetermined design specifications. Correspondingly, Figure 8 The Smith chart distribution of its fundamental impedance and second harmonic impedance is shown. The fundamental impedance is in the high-efficiency region (PAE>70%), while the PAE affected by the second harmonic impedance gradually deteriorates with increasing frequency (PAE<60%).

[0077] According to basic microwave circuit theory, harmonic suppression in filter performance means that the signal is completely reflected, and the corresponding impedance should be close to the edge of the Smith chart. In power amplifier design, regardless of the type of high-efficiency power amplifier, the high-efficiency region of the second harmonic impedance is always close to the edge of the Smith chart. Therefore, a filter impedance converter with good harmonic suppression capability can simultaneously control the fundamental and second harmonic frequencies to achieve a high-efficiency power amplifier. To this end, this invention introduces an equivalent T-shaped line, which is equivalent to having harmonic suppression function, i.e., harmonic impedance control function. λ / 4 lines. The design process involves combining T-shaped lines with... λ By simultaneously establishing the ABCD matrices of the λ / 4 transmission line and the T-line, we can obtain the design equation. Similarly, by establishing the ABCD matrices of the T-line and the λ / 4 transmission line, we obtain the equivalent design equation. Based on this equivalent design equation, we determine the characteristic impedance and electrical length of each segment of the transmission line.

[0078] ;

[0079] ;

[0080] Using this equivalent design method, the impedance can be calculated. Z 1. The difference between the equivalent length of a transmission line and a 90° electrical length. θ t impedance Z c and Z t Here, this design is set... θ c =30°.

[0081] Figure 9 The proposed 15-50Ω filter impedance converter is demonstrated in different... θ t Simulation under certain conditions | S 21 |Curve,|S 21 | is the forward propagation coefficient, which directly reflects the signal transmission capability from the input to the output. A value greater than 1 (or 0 dB) indicates that the circuit has gain (such as an amplifier), while a value less than 1 indicates the presence of loss. It is a core indicator for evaluating the circuit's performance. It can be seen that different designs have different levels of second harmonic suppression. Specifically, with… θ t As the frequency increases, the transmission zero point caused by the open stub line shifts to lower frequencies, and the harmonic suppression capability located in the gray position also gradually changes. Figure 10 The second harmonic impedance trajectory is shown. θ t =25°, 35°, 43° and 55°). exist θt At angles of 25°, 35°, and 55°, the second harmonic suppression is poor, leading to a decrease in efficiency. θ t At 43°, the second harmonic impedance is always within the high-efficiency region. This proves that the filter's harmonic suppression capability matches the harmonic impedance control function required by the power amplifier. Therefore, this design can utilize the filter's harmonic suppression function to achieve high efficiency in the power amplifier.

[0082] like Figure 11 As shown, the proposed broadband high-efficiency filtered power amplifier adopts a traditional topology ( Z s= Z L =50Ω), including bias network, input and output matching networks. The input matching network is designed with the optimal impedance at the amplifier input, obtained through load-source pulling. The bias network is a simple circuit consisting of capacitors and inductors that passes DC and blocks RF signals. The output matching network is the focus of this design, directly determining various aspects of the amplifier's performance. Based on the fundamental principles of harmonic-controlled high-efficiency power amplifiers, achieving a broadband high-efficiency power amplifier requires meeting three conditions: First, the fundamental impedance within the bandwidth must be at the required output impedance position of the amplifier; second, the second harmonic impedance must be designed according to high-efficiency theory at a suitable position on the edge of the Smith chart; and third, the matching circuit itself must have a simple structure and low loss.

[0083] This design incorporates filtering characteristics and utilizes harmonic impedance control to achieve waveform design, reducing power consumption and thus improving the amplifier's output power and efficiency. In modern high-performance power amplifier design, the "output matching network" has evolved into an "output harmonic tuning network." Its design goal is no longer merely to achieve fundamental impedance matching, but rather to synergistically optimize efficiency and output power by providing specific impedances at the fundamental and harmonic frequencies. In this design, a cross-shaped filter impedance converter serves as the output matching network. This output matching circuit employs a three-mode resonator, and its design simultaneously considers fundamental impedance transformation, harmonic impedance control, and filtering functions, forming a multifunctional, high-performance matching network, which is a key component of this power amplifier design.

[0084] To verify the effectiveness of the proposed design method, the designed power amplifier was fabricated and tested. The input matching network of the filter power amplifier proposed in this section is designed using the step impedance matching method. For example... Figure 12 The schematic diagram of the final input matching network is shown below, with the trajectory of the input matching impedance as follows: Figure 13 As shown, all parameters are within the high-efficiency range. The dielectric substrate used in this design is F4B with a dielectric constant of 2.65 and a substrate thickness of 0.5 mm. The transistor bias is set to a drain voltage of 28 V, a gate voltage of -2.8 V, and a drain current of 200 mA. Figure 14 The S-parameters of the final designed filter impedance converter are shown. S-parameters are used to describe the performance of signals in multiport networks. Specifically, |S... 11 This is called the input reflection coefficient, which measures the proportion of a signal reflected back from the input port. A smaller value (e.g., less than -10dB) indicates better input impedance matching, allowing energy to enter the circuit more easily. The implemented filter-converter has high selectivity and a wide range of harmonic suppression capabilities. For example... Figure 15 As shown, the fundamental impedance and second harmonic impedance of the filter impedance converter are both in the high efficiency region (PAE>70%).

[0085] This invention simulates and tests the performance of the designed power amplifier, wherein the gate bias voltage V GS =-2.8V, drain bias voltage V DS =28V. Figure 16 The layout dimensions of the designed filtered power amplifier are shown. In this design, the impedance of the transmission lines in the layout is basically consistent with the theoretical initial values. Figure 17 The small-signal S-parameters of the tested filtered power amplifier are displayed. Within the designed frequency range, the power amplifier exhibits a bandpass filter response, with small-signal gain fluctuating between 9 and 13 dB. Furthermore, |S 21 The test results show a rapid transition from the passband to the stopband at high frequencies, and a transmission zero is observed in the upper sideband near the operating frequency band, exhibiting good selectivity. The upper stopband rejection level is greater than 32dB (4.7-6.5GHz). 22 |is with|S 11 The corresponding output reflection coefficient represents the amount of energy reflected back into the network from the output port, and is used to evaluate the matching performance of the output end.

[0086] small signal S After the parameter tests are completed, a large-signal continuous wave test is performed on the power amplifier. A brief description of the test procedure: First, an Agilent E8257D signal generator provides an RF signal with an input power of 10dBm; then, the RF signal is amplified by a driver amplifier (using a PMA3-83MP+ chip, capable of amplifying the signal to 28dBm); next, the amplified signal is sent to the amplifier under test (DUT), both powered by a DC power supply; finally, the output signal of the DUT is displayed on the Keysight N9030B spectrum analyzer interface after passing through a 20dB attenuator. Figure 18 This presents the test results of the drain efficiency of a power amplifier as a function of frequency. The test frequency was 3-4 GHz, with a frequency interval of 0.1 GHz. During the test, the drain efficiency DE and the saturated output power P of the power amplifier were measured. outThe gain ranges are 68.6%-81.2%, 40-40.1dBm, and 11.1-12dB, respectively.

[0087] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention, and no reference numerals in the claims should be construed as limiting the scope of the claims.

[0088] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A broadband high-efficiency filtered power amplifier, characterized in that, It includes the power amplifier body and the output matching network connected to its output terminal; The output matching network is a broadband filter impedance converter, whose structure is based on a three-mode transversely coupled filter, which can achieve fundamental impedance matching in the passband and provide suppression characteristics at harmonic frequencies. The output matching network comprises multiple directly connected transmission lines, forming a first subnetwork, a second subnetwork, a third subnetwork, and a fourth subnetwork; The structure of the first sub-network and the second sub-network is configured to be equivalent to a λ / 4 transmission line with harmonic impedance control function, which is used to adjust the position of the harmonic impedance on the Smith chart. The first and second sub-networks each include three transmission lines, and the third and fourth sub-networks each include one transmission line. The characteristic impedance and electrical length of each transmission line are determined by the coupling matrix synthesis method so that the output matching network simultaneously meets the preset in-band matching, harmonic suppression and bandwidth specifications. The three resonant modes of the output matching network are not directly coupled and together form the passband of a three-mode bandpass filter.

2. A method for designing the output matching network of a broadband high-efficiency filtered power amplifier as described in claim 1, characterized in that, include: Determine the design specifications of the filter power amplifier, including center frequency, bandwidth, in-band return loss, and target fundamental impedance; Based on the theory of transversely coupled filters, the coupling matrix is ​​synthesized, and the resonant frequency and external quality factor required for the output matching network are calculated according to the coupling matrix. The resonant modes are mapped to the resonant conditions of a three-mode transverse filter, and the susceptance slope parameters of each mode are calculated. By using an equivalent circuit model, the filter structure is transformed into a matching network composed of multiple transmission lines, and the characteristic impedance and electrical length of each transmission line segment are determined.

3. The design method for the output matching network of a broadband high-efficiency filtered power amplifier according to claim 2, characterized in that, In the step of converting the filter structure into a matching network composed of multiple transmission line segments using an equivalent circuit model, and determining the characteristic impedance and electrical length of each transmission line segment: By combining the ABCD matrices of the T-type line and the λ / 4 transmission line, the equivalent design equation is obtained. Based on the equivalent design equation, the characteristic impedance and electrical length of each segment of the transmission line are determined.

4. The design method for the output matching network of a broadband high-efficiency filtered power amplifier according to claim 3, characterized in that, The output matching network is implemented using a microstrip line or stripline structure.

5. The design method for the output matching network of a broadband high-efficiency filtered power amplifier according to claim 2, characterized in that, Calculate the required resonant frequency and external quality factor for the output matching network based on the coupling matrix: ； ； in, f 0i The resonant frequency, QE i External quality factor M Si , M ii For elements of the coupling matrix, f 0 represents the center frequency, and FBW represents the bandwidth.

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