Patent Application
20240195380
The present application claims priority to Korean Patent Application No. 10-2022-0173225, filed Dec. 13, 2022, the entire contents of which is incorporated herein for all purposes by this reference.
The present invention relates to an input/output matching circuit having a coupled line with a low resistance characteristic and a broadband amplifier including the same.
In recent telecommunications systems, a keyword is ultra-fast large data transmission. Ultra-high frequency communication systems such as 5G communication and 6G communication have an advantage of being able to increase the data transmission rate using a wide bandwidth, but it is difficult to design a circuit with a wide range of operating bandwidth.
In order to implement this as a monolithic microwave integrated circuit (hereinafter referred to as MMIC), a wide range of operating bandwidth is essential. Among various blocks needed for MMIC-based systems, the amplifier is a key block that determines the overall operating bandwidth of the system. This is because the amplifier is generally a forefront circuit for both a transmitter and a receiver.
Traditionally, distributed amplifier (DA) topology is widely used in various broadband system applications due to flat gains and proper matching properties.
However, a distributed amplifier structure is generally difficult to apply in small and low power applications because of its large size and power consumption due to the requirements for long transmission lines and extensive transistor stages.
Therefore, a variety of approaches are proposed as an alternative to expand the motion bandwidth, but due to the characteristics of the narrowband input/output matching, a bandwidth achieved by these techniques does not meet the distributed amplifier.
It is an object of the present invention to provide an input/output matching circuit having a coupled line with a low resistance characteristic and a broadband amplifier including the same.
It is another object of the present invention to provide a broadband matching device which lowers characteristic resistance in a wide frequency band by using a coupled line, and amplifier including the same.
According to an aspect of the present invention, provided are an input/output matching circuit having a coupled line with a low resistance characteristic and a broadband amplifier including the same.
According to an embodiment of the present invention, a matching circuit connected to each of an input terminal and an output terminal of an amplifier may be provided, which includes: a coupled line circuit unit constituted by coupled lines having a 4-port structure, in which the coupled line includes a first metal line and a second metal line; and a first impedance restriction circuit unit connected to a through port among the 4 ports of the coupled line, and restricting an even mode impedance in a low frequency band.
According to another embodiment of the present invention, a differential amplifier may be provided, which includes: two input terminals having a differential structure; an amplification circuit unit amplifying signals of the two input terminals; at least one output terminal outputting the signals amplified by the amplification circuit unit; and a plurality of matching circuit units constituted by coupled lines having a 4-port structure, and connected to the two input terminals and the output terminal, respectively, and restricting an input/output impedance, in which each of the plurality of matching circuit units includes a resistance connected to a through port among the 4 ports of the coupled line, and a capacitor positioned between the coupled lines.
According to an embodiment of the present invention, an input/output matching circuit having a coupled line with a low resistance characteristic, and a broadband amplifier including the same are provided to lower characteristic resistance in a wide frequency band.
A singular form used in the present specification may include a plural form unless the context clearly dictates otherwise. In the present specification, a term such as “comprising” or “including” should not be interpreted as necessarily including all various components or various steps disclosed in the present specification, and it should be interpreted that some component or some steps among them may not be included or additional components or steps may be further included. In addition, the terms including “part”, “module”, and the like disclosed in the specification mean a unit that processes at least one function or operation and this may be implemented by hardware or software or a combination of hardware and software.
Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.
Referring to
As illustrated in
The input matching unit 110 is connected to two input terminals of the broadband amplifier 100 having a differential amplifier structure to perform input matching.
Since the amplifier 100 has the differential amplifier structure, the input matching unit 110 may be constituted by a first input matching circuit unit 110a and a second input matching circuit unit 110b. Here, the first input matching circuit unit 110a is connected to any one of two input terminals of the differential amplifier, and the second input matching circuit unit 110b is connected to the other one of two input terminals of the differential amplifier.
As illustrated in
Configurations of the first input matching circuit unit 110a and the second input matching circuit unit 110b are the same as each other. Therefore, the configuration of the matching circuit unit will be described in detail with reference to
The first and second input matching circuit units 110a and 110b are configured to include a coupled line circuit unit 210 including a coupled line having a 4-port structure, a first impedance restriction circuit unit 220, and a second impedance restriction circuit unit 230.
The coupled line circuit unit 210 is configured by the coupled line having the 4-port structure. That is, the coupled line may be a metal line, and will be referred to and described as a first line 210a and a second line 210b.
An input port is connected to one end of the first line 210a and a through port is connected to the other end of the first line 210a.
Further, an isolation port is connected to one end of the second line 210b coupled to the first line 210a, and the output port is connected to the other end of the second line 210b.
Accordingly, an input signal is input through the input port of the first line 210a, and is impedance-matched, and then is output to an input terminal of the amplifier through the output port.
The first impedance restriction circuit unit 220 is connected to the through port connected to the other end of the first line 210a.
Here, the first impedance restriction circuit unit 220 may be configured by a resistance. That is, the resistance may be connected to the through ports of the coupled lines 210a and 210b.
The first impedance restriction circuit unit 220 serves as resistive matching in a low frequency band. As a result, an even mode impedance is limited to a value which is twice the resistance connected to the through port.
The characteristic resistance of the coupled line may be derived through a log average of an even mode impedance and an odd mode impedance as shown in Equation 1:
wherein, Ls and Cs represent unit-length inductance and capacitance of a single transmission line in the coupled line structure, respectively, and Lm and Cm represent mutual inductance and capacitance between two transmission lines, respectively.
The resistance is connected to the through port of the coupled lines 210a and 210b like the first impedance restriction circuit unit 220 to serve as the resistive matching in the low frequency band in the range of several GHz to dozens of GHZ, so the value which is twice the resistance value may serve as an upper limit of the even mode impedance.
When the resistance is connected to the coupled line and the through port of the coupled line, frequency dependency of the even mode impedance in which the frequency dependency is small may be significantly lower as illustrated in (a) of
The second impedance restriction circuit unit 230 is connected between the coupled lines.
More specifically, as illustrated in
The input port of the first line 210a and the neighboring isolation port of the second line 210b may be connected to the first capacitor, and the through port of the first line 210a and the neighboring output port of the second line 210b may be connected to the second capacitor.
As shown in Equation 2, when a value of Cm; is adjusted, the odd mode impedance may be controlled without influencing the even mode impedance. A basic method of increasing the value of Cm is to make the coupled lines be close to each other, but this is restricted by a design rule of a manufacturing company, and does not provide a value of Cm which is enough to lower the odd mode impedance to almost several or tens of ohms.
Therefore, in an embodiment of the present disclosure, like the second impedance restriction circuit unit 230, the capacitors are connected between the input port and the output port of the coupled line, and other neighboring ports, respectively. As such, the connected capacitor has an effect of increasing a coupling capacitor Cm of the coupled line. Accordingly, there is an advantage in that the odd mode impedance may lower without influencing the even mode impedance.
As illustrated in
In
In summary, according to an embodiment of the present invention, the input matching unit 110 is connected to each of two input terminals of the broadband amplifier 100 having the differential structure, and is configured by a 4-port coupled line, and the resistance is connected to the through port among 4 ports of the coupled line, and each capacitor is connected between the coupled lines to match the characteristic resistance of the coupled line in a wide frequency band as 50 ohms.
The amplification unit 120 is a means for amplifying the input signal passing through the input matching unit 110, and outputting the amplified input signal to an output terminal. In an embodiment of the present invention, it is assumed that the amplifier is configured in four stages, and this is primarily illustrated, but an amplifier structure is not particularly limited to four stages.
Further, a general configuration and a general function of the amplification unit 120 are irrelevant to a main argument of the present invention, so a detailed description thereof will be omitted.
The output matching unit 130 is a means which is connected to the output terminal of the amplification unit 120, and matches an output impedance. A basic structure of the output matching unit 130 is the same as that of the input matching unit 110.
The output matching unit 130 is the same as the input matching unit 110 in that the output matching unit 130 has the 4-port structure coupled line circuit unit, the first impedance restriction circuit unit, and the second impedance restriction circuit unit, but unlike the input matching unit 110, the output matching unit 130 is used for matching the signal output by the amplification unit 120, and is different from the input matching unit 110 in that the output terminal, and the input port of the output matching unit 130 are connected.
A basic structure a basic operation are the same as those of the input matching unit 110, so a redundant description will be omitted.
As illustrated in
The present invention has been described above with reference to the embodiments thereof. It is understood to those skilled in the art that the present invention may be implemented as a modified form without departing from an essential characteristic of the present invention. Therefore, the disclosed embodiments should be considered in an illustrative viewpoint rather than a restrictive viewpoint. The scope of the present invention is defined by the appended claims rather than by the foregoing description, and all differences within the scope of equivalents thereof should be construed as being included in the present invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2022-0173225 | Dec 2022 | KR | national |
