阅读说明：本技术 一种基于耦合传输线的阻抗匹配电路 (Impedance matching circuit based on coupling 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,具体为一种基于耦合传输线的阻抗匹配电路。本发明阻抗匹配电路包括：一对差分耦合传输线,用于实现差分源阻抗与差分负载阻抗之间的阻抗匹配；初级并联电容,用于调整所述阻抗匹配电路初级的品质因数；次级并联电容,用于调整所述阻抗匹配电路次级的品质因数；初级馈电传输线,用于所述阻抗匹配电路初级的直流馈电；次级馈电传输线,用于所述阻抗匹配电路次级的直流馈电。本发明用极小的尺寸同时实现了射频功率放大器的阻抗匹配、直流馈电与直流隔离,并可以通过调整所述初级并联电容与所述次级并联电容的数值调整所述阻抗匹配电路的工作带宽。(The invention belongs to the technical field of electronics, and particularly relates to an impedance matching circuit based on a coupling transmission line. The impedance matching circuit of the present invention includes: a pair of differentially coupled transmission lines for implementing impedance matching between the differential source impedance and the differential load impedance; the primary parallel capacitor is used for adjusting the quality factor of the primary of the impedance matching circuit; a secondary parallel capacitor for adjusting the quality factor of the secondary of the impedance matching circuit; a primary feed transmission line for dc feeding of the primary of the impedance matching circuit; a secondary feed transmission line for direct current feeding of the impedance matching circuit secondary. The invention simultaneously realizes impedance matching, direct current feed and direct current isolation of the radio frequency power amplifier by using an extremely small size, and can adjust the working bandwidth of the impedance matching circuit by adjusting the numerical values of the primary parallel capacitor and the secondary parallel capacitor.)

1. An impedance matching circuit based on a coupled transmission line, comprising: a pair of differentially coupled transmission lines, a primary parallel capacitance, a secondary parallel capacitance, a primary feed transmission line, a secondary feed transmission line, wherein:

the pair of differential coupling transmission lines is used for realizing impedance matching between differential source impedance and differential load impedance;

the primary parallel capacitor is used for adjusting the quality factor of the primary of the impedance matching circuit;

the secondary parallel capacitor is used for adjusting the quality factor of the secondary side of the impedance matching circuit;

the primary feed transmission line is used for direct current feed of a primary impedance matching circuit;

the secondary feed transmission line is used for direct current feed of the impedance matching circuit secondary;

two ends of a primary coupling transmission line of the differential coupling transmission line are differential input ends of the impedance matching circuit, and two ends of a secondary coupling transmission line of the differential coupling transmission line are differential output ends of the impedance matching circuit;

the primary parallel capacitor is connected in parallel with two ends of a primary coupling transmission line of the differential coupling transmission line;

the secondary parallel capacitor is connected in parallel with two ends of a secondary coupling transmission line of the differential coupling transmission line;

the primary feed transmission line is connected to the midpoint of a primary coupling transmission line of the differential coupling transmission lines;

the secondary feed transmission line is connected to a midpoint of a secondary coupling transmission line of the differentially coupled transmission lines.

2. The impedance matching circuit of claim 1, wherein the lengths, widths, and spacings of the primary and secondary coupling transmission lines of the differentially coupled transmission line are adjusted based on the source impedance, the magnitude of the load impedance, and the required matching bandwidth to achieve optimal impedance matching.

3. The impedance matching circuit of claim 1, wherein the differentially coupled transmission line is implemented in the form of an integrated circuit or a printed circuit board.

4. The impedance matching circuit of claim 1, wherein the primary shunt capacitance or the secondary shunt capacitance is omitted, and the impedance matching circuit still has the effect of impedance matching;

(1) the primary parallel capacitor is omitted, and the secondary parallel capacitor is connected in parallel with two ends of the secondary coupling transmission line of the differential coupling transmission line and used for adjusting the quality factor of the secondary of the matching circuit; when the secondary parallel capacitance is increased, the quality factor of the secondary side of the matching circuit is improved, and the bandwidth of the matching circuit is reduced; meanwhile, the length of a secondary transmission line of the differential coupling transmission line is reduced, so that the area overhead of the power amplifier is saved;

(2) the secondary parallel capacitor is omitted, and the primary feed transmission line is connected to the midpoint of the primary coupling transmission line of the differential coupling transmission lines; the middle point of the primary coupling transmission line of the differential coupling transmission line is a virtual point, so the physical size of the primary feed transmission line cannot cause obvious influence on the performance of the matching circuit;

wherein the secondary feed transmission line is connected to a midpoint of a secondary coupling transmission line of the differentially coupled transmission lines; since the midpoint of the secondary coupling transmission line of the differential coupling transmission line is a virtual point, the physical size of the secondary feed transmission line does not significantly affect the performance of the matching circuit.

5. The impedance matching circuit of claim 1, wherein if the input end or the output end of the impedance matching circuit is a single-ended signal, and the other end is grounded, the impedance matching circuit has a function of converting the single-ended signal into a differential signal or converting the differential signal into the single-ended signal.

6. The impedance matching circuit of claim 5, wherein the input of the impedance matching circuit is a single-ended signal, and wherein the impedance matching circuit comprises: a pair of coupling transmission lines, a primary parallel capacitor, a secondary parallel capacitor, and a secondary feed transmission line; the coupling transmission line is used for realizing single-ended-differential conversion and impedance matching between single-ended source impedance and differential load impedance; the primary parallel capacitor is used for adjusting the quality factor of the primary of the impedance matching circuit; the secondary parallel capacitor is used for adjusting the quality factor of the secondary of the impedance matching circuit; the secondary feed transmission line is used for direct current feeding of the impedance matching circuit secondary.

7. The impedance matching circuit of claim 5, wherein the output of the impedance matching circuit is a single-ended signal, and the impedance matching circuit comprises: a pair of coupling transmission lines, a primary parallel capacitor, a secondary parallel capacitor, a primary feed transmission line; the coupling transmission line is used for realizing differential-single-ended conversion and impedance matching between differential source impedance and single-ended load impedance; the primary parallel capacitor is used for adjusting the quality factor of the primary of the impedance matching circuit; the secondary parallel capacitor is used for adjusting the quality factor of the secondary of the impedance matching circuit; the primary feed transmission line is for dc feeding of the primary of the impedance matching circuit.

Technical Field

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

Background

The rapid development of information technology has led to higher demands on communication systems, wherein a power amplifier is one of the most critical modules that limit the performance of a wireless communication system. How to design a broadband high-output power amplifier has been a hot spot of research in the industry. In order to break through the power bottleneck of the silicon-based power amplifier, the gallium arsenide, gallium nitride and other compound processes gradually become mainstream choices of the power amplifier process in a high-power application scene; however, the current power amplifier based on the compound technology usually adopts passive devices such as transmission lines and inductors to design an impedance matching circuit, and the area overhead and the insertion loss of the impedance matching circuit are both large, which will increase the processing cost of the power amplifier chip and reduce the performance of the power amplifier. Therefore, there is a need for a novel impedance matching circuit that has a low insertion loss while having a compact area.

Disclosure of Invention

The invention provides an impedance matching circuit based on a coupling transmission line, which can realize impedance matching, direct current feed and direct current isolation of a radio frequency power amplifier in an extremely small size, and can adjust the working bandwidth of the impedance matching circuit by adjusting the value of a parallel capacitor.

The invention provides an impedance matching circuit based on a coupling transmission line, which is used for realizing the interstage matching of a differential power amplifier and comprises the following components: a pair of differential coupling transmission lines, a primary parallel capacitor, a secondary parallel capacitor, a primary feed transmission line, a secondary feed transmission line; wherein:

the pair of differential coupling transmission lines is used for realizing impedance matching between differential source impedance and differential load impedance;

the primary parallel capacitor is used for adjusting the quality factor of the primary of the impedance matching circuit;

the secondary parallel capacitor is used for adjusting the quality factor of the secondary of the impedance matching circuit;

the primary feed transmission line is used for direct current feed of a primary impedance matching circuit;

the secondary feed transmission line is used for direct current feed of the impedance matching circuit secondary;

two ends of a primary coupling transmission line of the differential coupling transmission line are differential input ends of the impedance matching circuit, and two ends of a secondary coupling transmission line of the differential coupling transmission line are differential output ends of the impedance matching circuit;

the primary parallel capacitor is connected in parallel with two ends of a primary coupling transmission line of the differential coupling transmission line;

the secondary parallel capacitor is connected in parallel with two ends of a secondary coupling transmission line of the differential coupling transmission line;

the primary feed transmission line is connected to the midpoint of a primary coupling transmission line of the differential coupling transmission lines;

the secondary feed transmission line is connected to a midpoint of a secondary coupling transmission line of the differentially coupled transmission lines.

In the invention, the lengths, widths and intervals of the primary coupling transmission line and the secondary coupling transmission line of the differential coupling transmission line can be adjusted according to the values of the source impedance and the load impedance and the required matching bandwidth so as to achieve the optimal impedance matching.

In the invention, when the input signal is a differential signal, the midpoint of the primary coupling transmission line is a virtual point, so the primary feed transmission line will not affect the impedance matching function of the impedance matching circuit.

In the invention, when the input signal is a differential signal, the midpoint of the secondary coupling transmission line is a virtual point, so that the secondary feed transmission line will not influence the impedance matching function of the impedance matching circuit.

In the present invention, the differentially coupled transmission line may be implemented in the form of an integrated circuit or a printed circuit board.

In the invention, the primary parallel capacitor or the secondary parallel capacitor can be omitted, and the impedance matching circuit still has the effect of impedance matching.

In the invention, if the input end or the output end of the impedance matching circuit is a single-ended signal, the other end of the impedance matching circuit can be grounded, and the impedance matching circuit has the function of converting the single-ended signal into a differential signal or converting the differential signal into the single-ended signal. The concrete description is as follows:

the input end of the impedance matching circuit is a single-ended signal, and at this time, the impedance matching circuit based on the coupling transmission line is used for realizing the input matching of the differential power amplifier and comprises the following components: a pair of coupling transmission lines, a primary parallel capacitor, a secondary parallel capacitor, and a secondary feed transmission line. The coupling transmission line is used for realizing single-ended-differential conversion and impedance matching between single-ended source impedance and differential load impedance; the primary parallel capacitor is used for adjusting the quality factor of the primary of the impedance matching circuit; the secondary parallel capacitor is used for adjusting the quality factor of the secondary of the impedance matching circuit; the secondary feed transmission line is used for direct current feeding of the impedance matching circuit secondary.

The output end of the impedance matching circuit is a single-ended signal, and at this time, the impedance matching circuit based on the coupling transmission line is used for realizing the output matching of the differential power amplifier and comprises the following components: a pair of coupling transmission lines, a primary parallel capacitor, a secondary parallel capacitor, a primary feed transmission line. The coupling transmission line is used for realizing differential-single-ended conversion and impedance matching between differential source impedance and single-ended load impedance; the primary parallel capacitor is used for adjusting the quality factor of the primary of the impedance matching circuit; the secondary parallel capacitor is used for adjusting the quality factor of the secondary of the impedance matching circuit; the primary feed transmission line is for dc feeding of the primary of the impedance matching circuit.

The impedance matching circuit based on the coupling transmission line can reduce the area overhead of the impedance matching circuit and can realize broadband matching.

Drawings

Fig. 1 is a schematic diagram of an impedance matching circuit for interstage matching of a power amplifier according to an embodiment of the present invention.

Fig. 2 is a schematic diagram of an impedance matching circuit for power amplifier input matching according to an embodiment of the present invention.

Fig. 3 is a schematic diagram of an impedance matching circuit for matching output of a power amplifier according to an 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 impedance matching circuit for interstage matching of a power amplifier according to an embodiment of the present invention. As shown in fig. 1, the impedance matching circuit includes: a pair of differentially coupled transmission lines 101, a primary parallel capacitance 102, a secondary parallel capacitance 103, a primary feed transmission line 104, a secondary feed transmission line 105.

Two ends of a primary coupling transmission line of the differential coupling transmission line 101 are differential input ends of the impedance matching circuit 100, and two ends of a secondary coupling transmission line of the differential coupling transmission line are differential output ends of the impedance matching circuit 100; the differential coupling transmission line 101 has a symmetrical structure to ensure the balance of differential signals.

Preferably, the differential coupling transmission line 101 may be in a form of coupling upper and lower metal lines, or in a form of coupling adjacent metal lines on the same layer; the differential coupling transmission line 101 can achieve a higher coupling coefficient by selecting a coupling form of an upper metal wire and a lower metal wire, so that the insertion loss of the impedance matching circuit is reduced.

The primary parallel capacitor 102 is connected in parallel to two ends of the primary coupling transmission line of the differential coupling transmission line 101, and is used for adjusting the quality factor of the primary of the matching circuit 100; when the primary parallel capacitor 102 is increased, the quality factor of the primary of the matching circuit 100 is increased, so that the bandwidth of the matching circuit 100 is reduced; at the same time the length of the primary transmission line of the differentially coupled transmission line 101 will be reduced, thereby saving power amplifier area overhead.

Preferably, the primary parallel capacitor 102 may be omitted, and the impedance matching circuit may still have the function of impedance matching.

The secondary parallel capacitor 103 is connected in parallel to two ends of the secondary coupling transmission line of the differential coupling transmission line 101, and is used for adjusting the quality factor of the secondary of the matching circuit 100; when the secondary parallel capacitor 103 is increased, the quality factor of the secondary of the matching circuit 100 is increased, so that the bandwidth of the matching circuit 100 is reduced; at the same time the length of the secondary transmission line of the differentially coupled transmission line 101 will be reduced, saving power amplifier area overhead.

Preferably, the secondary parallel capacitor 103 may be omitted, and the impedance matching circuit may still have the function of impedance matching.

Wherein the primary feeding transmission line 104 is connected to the midpoint of the primary coupling transmission line of the differential coupling transmission line 101; since the midpoint of the primary coupling transmission line of the differential coupling transmission line 101 is a virtual ground point, the physical dimensions of the primary feed transmission line 104 will not significantly affect the performance of the matching circuit 100.

Wherein the secondary feeding transmission line 105 is connected to the midpoint of the secondary coupling transmission line of the differential coupling transmission line 101; since the midpoint of the secondary coupling transmission line of the differentially coupled transmission line 101 is a virtual ground, the physical dimensions of the secondary feed transmission line 105 will not significantly affect the performance of the matching circuit 100.

Preferably, the secondary feeding transmission line 105, as it is connected to the gate of the latter transistor, transmits a current close to zero; smaller line widths can be selected.

Fig. 2 is a schematic diagram of an impedance matching circuit for power amplifier input matching according to an embodiment of the present invention. As shown in fig. 2, an impedance matching circuit 200 for power amplifier input matching includes a pair of coupling transmission lines 201, a primary parallel capacitor 202, a secondary parallel capacitor 203, and a secondary feed transmission line 204.

One end of the primary coupling transmission line of the coupling transmission line 201 is grounded, and the other end is a single-ended input end of the impedance matching circuit 200 for power amplifier input matching; two ends of the secondary coupling transmission line of the coupling transmission line 201 are differential output ends of the impedance matching circuit 200 for power amplifier input matching.

The primary parallel capacitor 202 is connected in parallel to two ends of the primary coupling transmission line of the coupling transmission line 201, and is used for adjusting the quality factor of the primary of the impedance matching circuit 200;

the secondary parallel capacitor 203 is connected in parallel to two ends of the secondary coupling transmission line of the coupling transmission line 201, and is used for adjusting the quality factor of the secondary of the impedance matching circuit 200;

wherein, the secondary feeding transmission line 204 is connected to the midpoint of the secondary coupling transmission line of the coupling transmission line 201;

the impedance matching circuit 200 for power amplifier input matching provided by the embodiment of the invention has the functions of single-ended-differential conversion and impedance matching.

Fig. 3 is a schematic diagram of an impedance matching circuit for matching output of a power amplifier according to an embodiment of the present invention. As shown in fig. 3, an impedance matching circuit 300 for power amplifier output matching includes a pair of coupling transmission lines 301, a primary parallel capacitor 302, a secondary parallel capacitor 303, and a primary feed transmission line 304.

One end of the secondary coupling transmission line of the coupling transmission line 301 is grounded, and the other end is a single-ended output end of the impedance matching circuit 300 for matching the output of the power amplifier; the two ends of the primary coupling transmission line of the coupling transmission line 301 are the differential input ends of the impedance matching circuit 300 for power amplifier output matching.

The primary parallel capacitor 302 is connected in parallel to two ends of the primary coupling transmission line of the coupling transmission line 301, and is used for adjusting the quality factor of the primary of the impedance matching circuit 300;

the secondary parallel capacitor 303 is connected in parallel to two ends of the secondary coupling transmission line of the coupling transmission line 301, and is used for adjusting the quality factor of the secondary side of the impedance matching circuit 300;

wherein the primary feeding transmission line 304 is connected to the midpoint of the primary coupling transmission line of the coupling transmission line 301.

The impedance matching circuit 300 for matching the output of the power amplifier provided by the embodiment of the invention has the functions of differential-single-ended conversion and impedance matching.

The present invention may be implemented in any of the above-described embodiments. The invention simultaneously realizes impedance matching, direct current feed and direct current isolation of the radio frequency power amplifier by using an extremely small size, and simultaneously has the function of balun. And thus is well suited for the design of compact power amplifiers as well as wideband power amplifiers.

The above detailed description is provided for an impedance matching circuit based on a coupled transmission line according to an embodiment of the present invention, and a specific example is applied in this document to explain the principle and the implementation of the present invention, and the description of the above embodiment is only used to help understanding the method and the core idea of the present 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.