阅读说明：本技术 一种基于多节人工传输线的输入匹配电路 (Input matching circuit based on multisection artificial transmission line ) 是由 马顺利 章锦程 任俊彦 于 2020-04-11 设计创作，主要内容包括：本发明属于电子技术领域,具体为一种基于多节人工传输线的输入匹配电路。本发明输入匹配电路包括：第一电容、第二电容、第三电容、第四电容、第一电感、第二电感、隔直电容以及馈电电阻；第一电容、第二电容、第一电感构成第一人工传输线；第三电容、第四电容、第二电感构成第二人工传输线；第一人工传输线与第二人工传输线构成一个多节阻抗匹配电路。根据需要,还可以采用三节或更多节的人工传输线,第三人工传输线与第二人工传输线完全相同,两者并联得到阻抗为第二人工传输线一半的人工传输线。本发明可以实现功率放大器的宽带输入阻抗匹配。该电路尤其适用于氮化镓功率放大器的输入匹配,并可以灵活的控制输入匹配电路的带宽与带内波纹。(The invention belongs to the technical field of electronics, and particularly relates to an input matching circuit based on a plurality of sections of artificial transmission lines. The input matching circuit of the present invention includes: the first capacitor, the second capacitor, the third capacitor, the fourth capacitor, the first inductor, the second inductor, the blocking capacitor and the feed resistor; the first capacitor, the second capacitor and the first inductor form a first artificial transmission line; the third capacitor, the fourth capacitor and the second inductor form a second artificial transmission line; the first artificial transmission line and the second artificial transmission line form a multi-section impedance matching circuit. According to the requirement, three or more sections of artificial transmission lines can be adopted, the third artificial transmission line is completely the same as the second artificial transmission line, and the third artificial transmission line and the second artificial transmission line are connected in parallel to obtain the artificial transmission line with half of the impedance of the second artificial transmission line. The invention can realize the broadband input impedance matching of the power amplifier. The circuit is particularly suitable for input matching of a gallium nitride power amplifier, and the bandwidth and in-band ripple of the input matching circuit can be flexibly controlled.)

1. An input matching circuit based on a plurality of sections of artificial transmission lines, comprising: the first capacitor, the second capacitor, the third capacitor, the fourth capacitor, the first inductor, the second inductor, the blocking capacitor and the feed resistor; one ends of the first capacitor and the second capacitor are grounded, and the other ends of the first capacitor and the second capacitor are respectively connected with two ends of a first inductor; the three parts form a PI type first artificial transmission line; one ends of the third capacitor and the fourth capacitor are grounded, and the other ends of the third capacitor and the fourth capacitor are respectively connected with two ends of a second inductor; the three parts form a PI type second artificial transmission line; the first artificial transmission line and the second artificial transmission line form a multi-section impedance matching circuit.

2. The multi-section artificial transmission line based input matching circuit of claim 1, wherein the bandwidth of the matching circuit is determined by the characteristic impedance and electrical length of the first artificial transmission line and the second artificial transmission line, and the source impedance and the load impedance of the input matching circuit.

3. The multi-section artificial transmission line-based input matching circuit of claim 1, wherein the values of said first capacitor, said second capacitor and said first inductor are determined by the desired characteristic impedance and electrical length of said first artificial transmission line.

4. The multi-section artificial transmission line-based input matching circuit of claim 1, wherein values of said third capacitor, said fourth capacitor and said second inductor are determined by a desired characteristic impedance and electrical length of said second artificial transmission line.

5. The input matching circuit based on multiple sections of artificial transmission lines according to claim 1, wherein the feeder resistance is a large resistance in the kilo-ohm level, so that the feeder branch is embodied in a high-resistance state without affecting the performance of the input matching circuit.

6. The multi-section artificial transmission line based input matching circuit of claim 1, wherein said second capacitor and said third capacitor are combined into one capacitor.

7. The multi-section artificial transmission line-based input matching circuit of claim 1, wherein said multi-section impedance matching circuit is designed with a chebyshev response or a butterworth response to obtain a minimum reflection coefficient or an optimal operating bandwidth.

8. The multi-section artificial transmission line based input matching circuit of claim 7, wherein three or more sections of artificial transmission lines are used when better in-band flatness or out-of-band attenuation is required.

9. The input matching circuit based on multiple sections of artificial transmission lines according to claim 7, wherein when the characteristic impedance of the artificial transmission line required in the design of the input matching circuit is too low, a parallel artificial transmission line having the same electrical length as a single section of artificial transmission line and half the characteristic impedance of the single section of artificial transmission line can be obtained by connecting two identical sections of artificial transmission lines in parallel.

Technical Field

The invention belongs to the technical field of electronics, and particularly relates to an impedance matching circuit.

Background

With the continuous development of society, the requirement of people on the transmission speed of wireless communication is continuously improved; according to the aroma theorem, the transmission speed of a wireless communication system is proportional to the system bandwidth under the condition of the same signal-to-noise ratio. Therefore, increasing the radio frequency bandwidth of a communication system is one of the most direct methods for increasing the information transmission speed. In recent years, the millimeter wave band has become the popular choice for the next-generation communication technology due to its huge frequency bandwidth. As one of the most important modules in a wireless communication system, research on a millimeter wave broadband power amplifier has also gained wide attention; however, since the quality factor of the gate input impedance of the millimeter wave band transistor is generally high, the design of the broadband input matching circuit has been one of the difficulties in designing the broadband power amplifier. Therefore, there is a need for an input matching circuit that not only has the function of broadband matching, but also has good performance in terms of insertion loss, design complexity, and scalability.

Disclosure of Invention

The invention aims to provide an input matching circuit based on a plurality of sections of artificial transmission lines so as to realize broadband input impedance matching of a power amplifier.

The invention provides an input matching circuit based on a plurality of sections of artificial transmission lines, which comprises: the first capacitor, the second capacitor, the third capacitor, the fourth capacitor, the first inductor, the second inductor, the blocking capacitor and the feed resistor; one ends of the first capacitor and the second capacitor are grounded, and the other ends of the first capacitor and the second capacitor are respectively connected with two ends of a first inductor; the three parts form a PI type first artificial transmission line; one ends of the third capacitor and the fourth capacitor are grounded, and the other ends of the third capacitor and the fourth capacitor are respectively connected with two ends of a second inductor; the three parts form a PI type second artificial transmission line; the first artificial transmission line and the second artificial transmission line form a multi-section impedance matching circuit, and the broadband input impedance matching of the power amplifier can be realized.

In the invention, the bandwidth of the matching circuit is determined by the characteristic impedance and the electrical length of the first artificial transmission line and the second artificial transmission line, and the source impedance and the load impedance of the input matching circuit.

In the invention, the values of the first capacitor, the second capacitor and the first inductor are determined by the required characteristic impedance and electrical length of the first artificial transmission line.

In the invention, the values of the third capacitor, the fourth capacitor and the second inductor are determined by the required characteristic impedance and electrical length of the second artificial transmission line.

In the invention, the feed resistor is usually a large resistor of kilo-ohm level, so that the feed branch is embodied in a high-resistance state, and the performance of the input matching circuit is not influenced.

In the present invention, the second capacitor and the third capacitor may be combined into one capacitor.

In the invention, the multi-section impedance matching circuit can be designed by utilizing the Chebyshev response or the Butterworth response so as to obtain the minimum reflection coefficient or the optimal working bandwidth.

In the present invention, when better in-band flatness or out-of-band attenuation is required, three or more sections of artificial transmission lines may be employed.

In the invention, when the characteristic impedance of the artificial transmission line required in the design of the input matching circuit is too low, a parallel artificial transmission line with the same electrical length and the characteristic impedance of half of a single-section artificial transmission line can be obtained by adopting a parallel connection mode of two completely same artificial transmission lines.

The input matching circuit based on the multiple sections of artificial transmission lines can realize broadband input impedance matching of the power amplifier. The input matching circuit is particularly suitable for input matching of a gallium nitride power amplifier, and can flexibly control the bandwidth and the in-band ripple of the input matching circuit.

Drawings

Fig. 1 is a schematic diagram of an input matching circuit based on multiple sections of artificial transmission lines according to an embodiment of the present invention.

Fig. 2 is a schematic diagram of another input matching circuit based on multiple sections of artificial transmission lines provided in the embodiment of the present invention.

Detailed Description

The technical solution in the embodiments of the present invention will be fully described below with reference to the accompanying drawings in the embodiments of the present invention. The described embodiments are only some of the embodiments of the present invention, and do not limit the embodiments of the present 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.

Fig. 1 is a schematic diagram of an input matching circuit based on multiple sections of artificial transmission lines according to an embodiment of the present invention. As shown in fig. 1, the input matching circuit includes: a first capacitor 111, a second capacitor 112, a third capacitor 121, a fourth capacitor 122, a first inductor 113, a second inductor 123, a dc blocking capacitor 130 and a feeding resistor 140.

One end of the first capacitor 111 and one end of the second capacitor 112 are grounded, and the other end of the first capacitor 111 and the other end of the second capacitor 112 are respectively connected to two ends of the first inductor 113, so that the first capacitor 111 and the second capacitor form a PI-type first artificial transmission line 110.

One ends of the third capacitor 121 and the fourth capacitor 122 are grounded, and the other ends are respectively connected to two ends of the second inductor 123, so that the third capacitor 121 and the fourth capacitor 122 form a PI-type second artificial transmission line 120.

Preferably, the second capacitor 112 and the third capacitor 121 may be combined into one capacitor in an actual circuit implementation.

One end of the first artificial transmission line 110 is an input end of the input matching circuit 100, the other end of the first artificial transmission line is connected to one end of the second artificial transmission line 120, the other end of the second artificial transmission line is connected to the dc blocking capacitor 130, and the other end of the dc blocking capacitor 130 is a gate of the transistor.

The dc blocking capacitor 130 is a large capacitor with a high quality factor to reduce the influence on the impedance matching circuit 100; the feeding resistor 140 is usually a large resistor, so that the feeding branch is embodied in a high impedance state, which will not affect the input matching circuit 100.

The first artificial transmission line 110 and the second artificial transmission line 120 form a multi-section impedance matching circuit, which can implement wideband input impedance matching. When designing the input matching circuit 100, the required characteristic impedances and electrical lengths of the first artificial transmission line 110 and the second artificial transmission line 120 need to be calculated according to the source impedance and the load impedance, and then the values of the first capacitor 111, the second capacitor 112, the third capacitor 121, the fourth capacitor 122, the first inductor 113, and the second inductor 123 need to be calculated according to the characteristic impedances and the electrical lengths of the first artificial transmission line 110 and the second artificial transmission line 120.

Wherein the characteristic impedance Z of the artificial transmission line is given₀With respect to the electrical length θ, the corresponding capacitance and inductance values can be calculated by the formula:

preferably, the characteristic impedance and electrical length of the first artificial transmission line 110 and the second artificial transmission line 120 may have a plurality of values for the determined source impedance and load impedance, wherein the most practical values are the chebyshev response with the widest bandwidth or the butterworth response with the smallest in-band reflection coefficient.

Preferably, when better in-band flatness or out-of-band attenuation is required, three or more sections of artificial transmission lines may be employed; when the bandwidth requirement on the input matching circuit 100 is low, only one section of artificial transmission line can be adopted; the designer needs to trade off in-band flatness of the input matching circuit 100 against design complexity.

Fig. 2 is a schematic diagram of another input matching circuit based on multiple sections of artificial transmission lines provided in the embodiment of the present invention. In the design of the input matching circuit of the practical power amplifier, the minimum characteristic impedance which can be realized by the artificial transmission line is about 15 ohms, and the real part of the input impedance of the transistor in the gallium nitride process and the like is small, so that the situation that the required characteristic impedance of the artificial transmission line is too low to realize is met. In the exemplary embodiment of fig. 2, two parallel sections of artificial transmission line are used to achieve an artificial transmission line with a lower required characteristic impedance. The input matching circuit includes: a first capacitor 211, a second capacitor 212, a third capacitor 221, a fourth capacitor 222, a fifth capacitor 231, a sixth capacitor 232, a first inductor 213, a second inductor 223, a third inductor 233, a dc blocking capacitor 240 and a feeding resistor 250.

One end of each of the first capacitor 211 and the second capacitor 212 is grounded, and the other end of each of the first capacitor 211 and the second capacitor 212 is connected to two ends of the first inductor 213, so that a PI-type first artificial transmission line 210 is formed by the first capacitor 211 and the second capacitor; one ends of the third capacitor 221 and the fourth capacitor 222 are grounded, and the other ends are respectively connected with two ends of the second inductor 223, so that a PI-type second artificial transmission line 220 is formed by the third capacitor 221 and the fourth capacitor 222; one ends of the fifth capacitor 231 and the sixth capacitor 232 are grounded, and the other ends are respectively connected with two ends of the second inductor 233, so that the fifth capacitor 231 and the sixth capacitor 232 form a PI-type third artificial transmission line 230.

The third capacitor 221, the fourth capacitor 222, and the second inductor 223 are completely the same as the fifth capacitor 231, the sixth capacitor 232, and the second inductor 233, respectively. The second artificial transmission line 220 is connected in parallel with the third artificial transmission line 230, thereby obtaining an artificial transmission line having an electrical length equal to that of the second artificial transmission line 220 and a characteristic impedance equal to one-half of that of the second artificial transmission line 220.

The invention provides an input matching circuit based on a multi-section artificial transmission line aiming at the condition that the input matching in a power amplifier is difficult to design due to the large impedance transformation ratio, the input matching circuit is suitable for the design of power amplifiers of various processes, and the bandwidth and the in-band ripple of the input matching circuit can be flexibly controlled.

The input matching circuit based on multiple sections of artificial transmission lines provided by the embodiment of the invention is described in detail above, a specific example is applied in the text to explain the principle and the implementation of the invention, and the description of the above embodiment is only used to help understand the method and the core idea of the invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.