阅读说明：本技术 一种宽带谐波抑制射频功率放大器结构及其设计方法 (Broadband harmonic suppression radio frequency power amplifier structure and design method thereof ) 是由 韩克锋 于 2019-08-16 设计创作，主要内容包括：本发明公开了一种宽带谐波抑制射频功率放大器结构及其设计方法；本发明提出的基于多谐波反射短截线组合的宽带谐波抑制结构可以实现对射频功放的谐波发射功率进行有效的宽带抑制；采用本发明提出的基于电容拆解和谐波抑制短截线等效变换的设计方法,可以大大降低多谐波抑制短截线组合的宽带谐波抑制匹配网络的设计难度；对于微波、毫米波放大电路和发射系统等应用,采用本发明提出的结构和方法实现电路及系统的宽带谐波抑制具有积极意义。(The invention discloses a broadband harmonic suppression radio frequency power amplifier structure and a design method thereof; the broadband harmonic suppression structure based on the multi-harmonic reflection stub combination can realize effective broadband suppression of the harmonic emission power of the radio frequency power amplifier; by adopting the design method based on capacitance disassembly and harmonic suppression stub equivalent transformation, the design difficulty of the broadband harmonic suppression matching network combined by the multi-harmonic suppression stub can be greatly reduced; the structure and the method provided by the invention have positive significance for realizing broadband harmonic suppression of circuits and systems for application of microwave and millimeter wave amplifying circuits, transmitting systems and the like.)

1. A broadband harmonic suppression radio frequency power amplifier structure is characterized by comprising a transistor, wherein an input end of the transistor is provided with an input matching network and a stabilizing network formed by connecting C05 and R1 in parallel; the drain of the transistor is connected with a second harmonic short-circuit line (104) to realize the quasi short-circuit condition of the second harmonic, and a third harmonic short-circuit line (105) to realize the quasi short-circuit condition of the third harmonic, and then the following drain direct current feeder (100), an impedance matching stub (106), a DC blocking capacitor (C04), a harmonic suppression stub (101), an impedance matching stub (107), a harmonic suppression stub (102), an impedance matching stub (108), and a harmonic suppression stub (103) are connected through a microstrip line, and the drain direct current feeder (100) not only serves as a direct current feeder, but also plays a role in reflecting and suppressing the second harmonic.

2. The wideband harmonic rejection radio frequency power amplifier architecture according to claim 1, wherein a second harmonic short circuit line (104) is provided in parallel at the drain of the transistor, employing a second harmonic 90 ° open stub in parallel; the third harmonic short circuit line (105) is arranged at the drain of the transistor in parallel, and a parallel third harmonic 90-degree open-circuit stub is adopted.

3. The wideband harmonic-rejection radio frequency power amplifier architecture according to claim 1, further falling within the scope of the present invention by increasing or decreasing the number of harmonic shorting lines, harmonic rejection stubs in the transistor drain and output impedance matching networks to achieve harmonic impedance quasi-short conditions, harmonic reflections and rejection at fewer or more harmonics.

4. The wideband harmonic-rejection radio frequency power amplifier architecture according to claim 1, based on which wideband harmonic rejection is achieved by increasing or decreasing the number of harmonic short-circuit lines, harmonic-rejection stubs, and tuning the length, also falling within the scope of the present invention.

5. The method of designing a wideband harmonic rejection radio frequency power amplifier structure as claimed in claim 1, including the steps of:

s1, load impedance transformation is carried out based on the low-pass LC ladder-shaped network, and port impedance is transformed to the optimal load impedance of the transistor at the fundamental frequency;

s2, disassembling parallel capacitors in the low-pass LC ladder-shaped network, and enabling the impedance value of a part of disassembled capacitors at the fundamental frequency to be equal to the fundamental frequency impedance of the open stub with the specific harmonic wave of 90 degrees;

s3, replacing the capacitor with the same impedance value of the fundamental frequency, which is disassembled in the step S2, by the specific harmonic 90-degree open stub to realize the reflection and the suppression of the specific harmonic, wherein the specific harmonic 90-degree open stub becomes the harmonic suppression stub of the specific harmonic after being added into the network;

and S4, transforming the residual lumped elements in the network into an equivalent microstrip network.

Technical Field

The invention belongs to the technical field of radio frequency communication, and particularly relates to a broadband harmonic suppression radio frequency power amplifier structure and a design method thereof.

Background

In the fields of microwave and millimeter wave radar, communication and the like, relevant standards have strict requirements on harmonic transmission power of a radio frequency power amplification circuit and a radio frequency transmission system. The radio frequency power amplifying circuit is widely applied to radio systems of communication, navigation, identification, measurement and control, broadcast television, remote sensing and remote measurement, radio astronomy, electronic countermeasure and other applications, and the harmonic suppression characteristic of the radio frequency power amplifying circuit is a more key index in the applications. The design of the broadband harmonic suppression radio frequency power amplifying circuit is difficult to realize based on the existing circuit structure and design method.

Disclosure of Invention

The technical problem to be solved by the present invention is to provide a broadband harmonic suppression rf power amplifier structure and a design method thereof, so as to improve the harmonic suppression characteristics of the rf power amplifier circuit.

The invention adopts the following technical scheme:

the invention provides a broadband harmonic suppression radio frequency power amplifier structure, which adopts an impedance matching network comprising a multi-harmonic reflection microstrip stub structure to carry out load impedance matching of the radio frequency power amplifier and realize broadband harmonic suppression; the output end of the transistor is connected with a microstrip open-circuit stub line with a specific electrical length in parallel, the microstrip open-circuit stub line is used as a harmonic short-circuit line to introduce a harmonic quasi-short-circuit condition, and a harmonic load impedance value seen by the output end of the transistor is fixed; the drain electrode is used for providing a microstrip line for direct current bias and feeding, and is also used for reflecting and suppressing a second harmonic; the structure has positive significance for realizing broadband harmonic suppression of circuits and systems.

Furthermore, a second harmonic 90-degree open stub connected in parallel is added into the output matching circuit, and the second harmonic 90-degree open stub connected in parallel is used as a second harmonic suppression stub to reflect and suppress second harmonics in the output power of the power amplifier.

Further, it is also possible to reflect and suppress the second harmonic and the third harmonic in the output power of the power amplifier by adding a second harmonic 90 ° open stub and a third harmonic 90 ° open stub in parallel as a second harmonic suppression stub and a third harmonic suppression stub, respectively, to the output matching circuit.

Further, reflection and suppression of broadband harmonics can also be realized by adding more 90 ° open stubs aiming at specific harmonics in the output matching circuit, wherein the 90 ° open stubs of the specific harmonics are used as harmonic suppression stubs of the specific harmonics to reflect and suppress more harmonics in the output power of the power amplifier, or by performing parameter tuning and combination on the 90 ° open stubs of the harmonics;

furthermore, the harmonic short circuit line with a specific electric length arranged at the output end of the transistor is used for reflecting harmonic signals and carrying out harmonic suppression besides fixing the harmonic load impedance value of the transistor.

The invention provides a design method of a broadband harmonic suppression radio frequency power amplifier structure, in a broadband harmonic suppression power amplifier with a multi-harmonic reflection microstrip stub structure, an output network needs to introduce a harmonic suppression stub to realize harmonic suppression and needs to complete output impedance conversion and matching, the design of the broadband harmonic suppression radio frequency power amplifier structure is challenging and targeted, the invention provides an effective and easy-to-implement design method of the broadband harmonic suppression power amplifier facing the multi-harmonic reflection microstrip stub structure, which mainly comprises four steps,

s1, load impedance transformation is carried out based on the low-pass LC ladder-shaped network, and port impedance is transformed to the optimal load impedance of the transistor at the fundamental frequency;

s2, disassembling parallel capacitors in the low-pass LC ladder-shaped network, and enabling the impedance value of a part of disassembled capacitors at the fundamental frequency to be equal to the fundamental frequency impedance of the open stub with the specific harmonic wave of 90 degrees;

s3, replacing the capacitance with the same fundamental frequency impedance value with the capacitance disassembled in the step S2 by the specific harmonic 90-degree open stub, and realizing the reflection of the specific harmonic and the inhibition of the specific harmonic 90-degree open stub to be added into the network to be the harmonic inhibition stub of the specific harmonic;

and S4, transforming the residual lumped elements in the network into an equivalent microstrip network.

In summary, the broadband harmonic suppression power amplifier structure based on the multi-harmonic reflection microstrip stub can be effectively applied to the design and development of radio frequency power amplification circuits with harmonic suppression requirements, and the suppression of multiple harmonics and the realization of broadband suppression of the harmonics can be realized based on the circuit structure provided by the invention; the design method of the broadband harmonic suppression radio frequency power amplifier structure is an effective and easy-to-implement design method of a harmonic suppression power amplification circuit.

The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.

Drawings

FIG. 1 is a schematic diagram of an amplifier according to the present invention;

FIG. 2 is a diagram of a low pass LC ladder output matching network;

FIG. 3 is an exploded view of a low pass LC ladder network capacitor;

FIG. 4 is a partial capacitance replacement by a harmonic rejection stub;

fig. 5 shows the replacement of the remaining lumped elements by an equivalent network of microstrip lines.

Wherein: 100. a direct current feeder; 101. a third harmonic rejection stub; 102. a second harmonic rejection stub; 103. a third harmonic rejection stub; 104. a second harmonic short-circuit line; 105. a third harmonic short-circuit line; 106. a first matching stub; 107. a second matching stub; 108. a third matching stub; 109. a dc bias line.

Detailed Description

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Referring to fig. 1, the present invention provides a broadband harmonic suppression rf power amplifier structure, wherein an input end of a transistor is provided with an input matching network and a stabilizing network formed by connecting C05 and R1 in parallel; the drain of the transistor is connected with a second harmonic short-circuit line (104) to realize the quasi short-circuit condition of the second harmonic, and a third harmonic short-circuit line (105) to realize the quasi short-circuit condition of the third harmonic, and then the following drain direct current feeder (100), an impedance matching stub (106), a DC blocking capacitor (C04), a harmonic suppression stub (101), an impedance matching stub (107), a harmonic suppression stub (102), an impedance matching stub (108), and a harmonic suppression stub (103) are connected through a microstrip line, and the drain direct current feeder (100) not only serves as a direct current feeder, but also plays a role in reflecting and suppressing the second harmonic.

The amplifier structure of the invention is different from the traditional output matching network:

1. an equivalent second harmonic 90 DEG open stub (104) and an equivalent third harmonic 90 DEG open stub (105) are connected in parallel adjacent to the transistor output (drain), and they function as:

determining the second harmonic and third harmonic load impedance of the output end of the transistor and reflecting the second harmonic and third harmonic.

Preferably, only one equivalent 90 ° open stub for one specific harmonic is provided adjacent to the transistor output; a plurality of equivalent 90-degree open stubs and the like aiming at a plurality of different harmonics can be added;

2. the direct current feeder (100), the harmonic suppression stub (101), the harmonic suppression stub (102), the harmonic suppression stub (103), the harmonic short-circuit line (104) and the harmonic short-circuit line (105) are used as feeders or participate in impedance matching, and simultaneously play a role in suppressing specific harmonics respectively; the harmonic suppression of specific harmonic and the harmonic suppression of broadband signals can be realized by properly selecting and configuring the number and the electrical length of the harmonic short-circuit lines and the harmonic suppression stubs.

The invention discloses a structural design method of a broadband harmonic suppression radio frequency power amplifier, which comprises the following steps of:

s1, load impedance transformation is carried out based on the low-pass LC ladder-shaped network, and port impedance is transformed to the optimal load impedance of the transistor at the fundamental frequency;

referring to fig. 2, an example of the low-pass LC ladder network includes a capacitor C1, a capacitor C2, and a capacitor C3, wherein one end of the capacitor C1 is connected in parallel with one end of the inductor L1, and the other end is grounded; one end of the capacitor C2 is respectively connected in parallel with the other end of the inductor L1 and one end of the inductor L2, and the other end is grounded; one end of the capacitor C3 is connected in parallel with the other end of the inductor L3, and the other end is grounded.

S2, disassembling the capacitance in the low-pass LC ladder network, as shown in FIG. 3;

referring to fig. 3, C1, C2 and C3 are respectively disassembled into C11+ C12, C21+ C22 and C31+ C32, wherein the impedances of C12, C22 and C32 at the fundamental frequency are respectively equivalent to the length of the fundamental frequencyAndthe impedance of the open-circuit short-section microstrip line at the fundamental frequency, wherein lambda is the wavelength of the fundamental frequency, n₁、n₂、n₃Taking the value as an integer;

s3, using the length ofTL1 of lengthTL2 and a length ofThe open-circuit short-section microstrip line of TL3 replaces C12, C22 and C32 in FIG. 3, and TL1, TL2 and TL3 are respectively aligned to n₁Subharmonic, n₂Subharmonic, n₃The sub-harmonics are suppressed as shown in fig. 4;

s4, transforming other lumped elements in the network into an equivalent microstrip network.

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Based on the structure and the method provided by the invention, the radio frequency power amplifier with the broadband harmonic suppression characteristic is realized, and based on the plate level design of the GaN HEMT discrete transistor, the typical indexes are as follows:

the working frequency is as follows: 2300-2700 MHz; gain: 15.5 dB; output power: 48 dBm; efficiency: 70 percent;

harmonic suppression: the second harmonic suppression ratio is larger than 40dBc and the third harmonic suppression ratio is larger than 45dBc within the frequency range of 2300-2900 MHz.

In summary, the structure and the method provided by the invention have positive significance for realizing broadband harmonic suppression of circuits and systems for microwave and millimeter wave amplification circuits, transmitting systems and other applications.

The above-mentioned contents are only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited thereby, and any modification made on the basis of the technical idea of the present invention falls within the protection scope of the claims of the present invention.