阅读说明：本技术 一种具有低插入损耗和平坦负群时延特性的宽带微波电路 (Broadband microwave circuit with low insertion loss and flat negative group delay characteristics ) 是由 孟雨薇 王钟葆 韩鹏 刘宏梅 傅世强 房少军 于 2021-08-10 设计创作，主要内容包括：本发明提供一种具有低插入损耗和平坦负群时延特性的宽带微波电路,包括：输入端口、微带线、并联枝节和输出端口。其中,微带线包括从左到右依次连接的输入微带线、连接微带线和输出微带线；并联枝节包括结构和尺寸均相同的第一并联枝节和第二并联枝节；第一并联枝节包括短路传输线、开路传输线、串联传输线、吸收电阻、二分之一波长传输线和四分之一波长传输线；本发明提供的宽带微波电路能够实现宽带平坦负群时延特性,而且具有插入损耗较小,群时延波动小以及输入输出端口良好匹配等优点。本发明的技术方案解决了插入损耗过大、输入输出端口匹配性能差、负群时延带宽内群时延值波动较大等问题。(The invention provides a broadband microwave circuit with low insertion loss and flat negative group delay characteristics, which comprises: input port, microstrip line, parallelly connected minor matters and output port. The microstrip lines comprise an input microstrip line, a connecting microstrip line and an output microstrip line which are sequentially connected from left to right; the parallel branches comprise a first parallel branch and a second parallel branch which are the same in structure and size; the first parallel branch section comprises a short circuit transmission line, an open circuit transmission line, a series connection transmission line, an absorption resistor, a half-wavelength transmission line and a quarter-wavelength transmission line; the broadband microwave circuit provided by the invention can realize the characteristic of broadband flat negative group delay, and has the advantages of smaller insertion loss, small group delay fluctuation, good matching of input and output ports and the like. The technical scheme of the invention solves the problems of overlarge insertion loss, poor matching performance of the input and output ports, large group delay value fluctuation in the negative group delay bandwidth and the like.)

1. A wideband microwave circuit having low insertion loss and flat negative group delay characteristics, comprising: the device comprises an input port (1), a microstrip line (2), a parallel branch (3) and an output port (4); wherein:

the microstrip line (2) comprises an input microstrip line (21), a connecting microstrip line (22) and an output microstrip line (23) which are sequentially connected from left to right; one end of the input microstrip line (21) is connected with the input port (1), and the other end of the input microstrip line is connected with the connecting microstrip line (22); one end of the output microstrip line (23) is connected with the connecting microstrip line (22), and the other end of the output microstrip line is connected with the output port (4);

the parallel branch sections (3) comprise a first parallel branch section (31) and a second parallel branch section (32) which are identical in structure and size; the first parallel branch (31) is connected with the connection part of the input microstrip line (21) and the connection microstrip line (22); the second parallel branch (32) is connected to the connection part of the output microstrip line (23) and the connection microstrip line (22);

the first parallel branch (31) comprises a short circuit transmission line (311), an open circuit transmission line (312), a series transmission line (313), an absorption resistor (314), a half-wavelength transmission line (315) and a quarter-wavelength transmission line (316); the short circuit transmission line (311) is connected with the series transmission line (313) after being connected with the open circuit transmission line (312) in parallel, is connected with the half-wavelength transmission line (315) in series through the absorption resistor (314), and is finally connected with the quarter-wavelength transmission line (316).

2. A broadband microwave circuit with low insertion loss and flat negative group delay characteristics according to claim 1, characterized in that the characteristic impedance of the microstrip line (2) is Z₄The characteristic impedance of the short-circuit transmission line (311) is equal to the characteristic impedance of the open-circuit transmission line (312), and both are Z₁The characteristic impedance of the series transmission line (313) is equal to the characteristic impedance of the half-wavelength transmission line (315), both Z and Z being equal₂The absorption resistor (314) has a resistance value of R, and the quarter-wave transmission line (316) has a characteristic impedance of Z₃。

3. A broadband microwave circuit with low insertion loss and flat negative group delay characteristics according to claim 1, wherein the broadband microwave circuit implements the conditions of low insertion loss and flat negative group delay as follows:

the lengths of the short-circuit transmission line (311) and the open-circuit transmission line (312) are three eighths of the wavelength corresponding to the center frequency;

the length of the series transmission line (313) and the quarter-wavelength transmission line (316) is one quarter of the wavelength corresponding to the center frequency;

the length of the half-wavelength transmission line (315) is one half of the wavelength corresponding to the center frequency;

the length of the input microstrip line (21), the connecting microstrip line (22) and the output microstrip line (23) is one quarter of the wavelength corresponding to the central frequency.

4. A broadband microwave circuit with low insertion loss and flat negative group delay characteristics according to claim 1, characterized in that the broadband microwave circuit adjusts the magnitude of insertion loss and the flatness of group delay by changing the characteristic impedance of the short-circuit transmission line (311), the open-circuit transmission line (312), the series transmission line (313), the half-wavelength transmission line (315), the quarter-wavelength transmission line (316) and the microstrip line (2).

Technical Field

The present invention relates to a microwave circuit, and more particularly, to a broadband microwave circuit having low insertion loss and flat negative group delay characteristics.

Background

Negative group delay circuits are currently of increasing interest and have been applied in many circuits, such as in combination with amplifiers to enhance efficiency, to compensate for beam squints of series fed antenna arrays, as non-foster elements and in cascade with other circuit elements to equalize the group delay of the system, etc.

In recent years, in order to obtain a high-performance negative group delay circuit, researchers have proposed many new technologies, such as a signal interference technology, a filtering theory technology, and a lossless transmission line loading resistor, and design a negative group delay circuit based on a lossy transmission line or a distributed amplifier. However, the negative group delay generated by these circuits is not flat at the center frequency, and cannot meet the requirements of practical applications.

In order to obtain a flat negative group delay characteristic, a method of cascading two negative group delay circuits operating at different frequencies is proposed by the scholars, but the flat negative group delay realized by the method has a narrow bandwidth and a large attenuation, and the circuit size is increased due to a multi-stage structure. Then, the students use the characteristics of the dual-frequency negative group delay circuit to realize a flat group delay by approaching two operating frequencies. Still other researchers have proposed methods that combine the flat negative group delay characteristic with a power divider or coupler. Although these circuits are capable of achieving a flat negative group delay characteristic, the attenuation is relatively large.

Disclosure of Invention

In light of the technical problems set forth above, a broadband microwave circuit with low insertion loss and flat negative group delay characteristics is provided. The invention can realize the broadband flat negative group delay characteristic and has the advantages of smaller insertion loss, small group delay fluctuation, good matching of input and output ports and the like.

The technical means adopted by the invention are as follows:

a broadband microwave circuit having low insertion loss and flat negative group delay characteristics, comprising: the input port, microstrip line, parallel branch and output port; wherein:

the microstrip lines comprise an input microstrip line, a connecting microstrip line and an output microstrip line which are sequentially connected from left to right; one end of the input microstrip line is connected with the input port, and the other end of the input microstrip line is connected with the connecting microstrip line; one end of the output microstrip line is connected with the connecting microstrip line, and the other end of the output microstrip line is connected with the output port;

the parallel branches comprise a first parallel branch and a second parallel branch which are identical in structure and size; the first parallel branch is connected with the connection part of the input microstrip line and the connection microstrip line in a nodal manner; the second parallel branch is connected with the joint of the output microstrip line and the connecting microstrip line;

the first parallel branch section comprises a short circuit transmission line, an open circuit transmission line, a series connection transmission line, an absorption resistor, a half-wavelength transmission line and a quarter-wavelength transmission line; the short circuit transmission line is connected with the series transmission line after being connected with the open circuit transmission line in parallel, is connected with the half-wavelength transmission line in series through the absorption resistor, and is finally connected with the quarter-wavelength transmission line.

Further, the characteristic impedance of the microstrip line is Z₄The characteristic impedance of the short-circuit transmission line is equal to that of the open-circuit transmission line, and both are Z₁The characteristic impedance of the series transmission line is equal to that of the half-wavelength transmission line, and both are Z₂The resistance value of the absorption resistor is R, and the characteristic impedance of the quarter-wavelength transmission line is Z₃。

Further, the broadband microwave circuit realizes the conditions of low insertion loss and flat negative group delay as follows:

the length of the short circuit transmission line and the open circuit transmission line is three eighths of the wavelength corresponding to the center frequency;

the length of the series transmission line and the quarter-wavelength transmission line is one quarter of the wavelength corresponding to the center frequency;

the length of the half-wavelength transmission line is one half of the wavelength corresponding to the central frequency;

the length of the input microstrip line, the connecting microstrip line and the output microstrip line is one fourth of the wavelength corresponding to the central frequency.

Furthermore, the broadband microwave circuit adjusts the size of the insertion loss and the flatness of the group delay by changing the characteristic impedance of the short circuit transmission line, the open circuit transmission line, the series connection transmission line, the half-wavelength transmission line, the quarter-wavelength transmission line and the microstrip line.

Compared with the prior art, the invention has the following advantages:

1. the broadband microwave circuit with low insertion loss and flat negative group delay characteristics solves the problems of overlarge insertion loss, poor input and output port matching performance, large group delay value fluctuation in the negative group delay bandwidth and the like.

2. The broadband microwave circuit with low insertion loss and flat negative group delay characteristics provided by the invention can realize the broadband flat negative group delay characteristics, and has the advantages of small insertion loss, small group delay fluctuation, good matching of input and output ports and the like.

Based on the reasons, the invention can be widely popularized in the fields of application of various radio frequency microwave systems and the like.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic diagram of a broadband microwave circuit with low insertion loss and flat negative group delay characteristics according to the present invention;

FIG. 2 is a group delay plot of a broadband microwave circuit with low insertion loss and flat negative group delay characteristics according to the present invention;

FIG. 3 is a S-parameter curve diagram of a broadband microwave circuit with low insertion loss and flat negative group delay characteristics according to the present invention;

in the figure: 1. an input port; 2. a microstrip line; 21. inputting a microstrip line; 22. connecting a microstrip line; 23. outputting a microstrip line; 3. branch nodes are connected in parallel; 31. a first parallel branch segment; 32. a second parallel branch; 311. a short-circuit transmission line; 312. an open transmission line; 313. a series transmission line; 314. an absorption resistance; 315. a half-wavelength transmission line; 316. a quarter-wavelength transmission line; 4. and (6) an output port.

Detailed Description

It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

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 only a part of the embodiments of the present invention, and not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses. 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.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

The relative arrangement of the components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective portions shown in the drawings are not drawn in an actual proportional relationship for the convenience of description. Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate. Any specific values in all examples shown and discussed herein are to be construed as exemplary only and not as limiting. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

In the description of the present invention, it is to be understood that the orientation or positional relationship indicated by the directional terms such as "front, rear, upper, lower, left, right", "lateral, vertical, horizontal" and "top, bottom", etc., are generally based on the orientation or positional relationship shown in the drawings, and are used for convenience of description and simplicity of description only, and in the absence of any contrary indication, these directional terms are not intended to indicate and imply that the device or element so referred to must have a particular orientation or be constructed and operated in a particular orientation, and therefore should not be considered as limiting the scope of the present invention: the terms "inner and outer" refer to the inner and outer relative to the profile of the respective component itself.

Spatially relative terms, such as "above … …," "above … …," "above … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial relationship to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is turned over, devices described as "above" or "on" other devices or configurations would then be oriented "below" or "under" the other devices or configurations. Thus, the exemplary term "above … …" can include both an orientation of "above … …" and "below … …". The device may be otherwise variously oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

It should be noted that the terms "first", "second", and the like are used to define the components, and are only used for convenience of distinguishing the corresponding components, and the terms have no special meanings unless otherwise stated, and therefore, the scope of the present invention should not be construed as being limited.

As shown in fig. 1, the present invention provides a broadband microwave circuit with low insertion loss and flat negative group delay characteristics, comprising: the device comprises an input port 1, a microstrip line 2, a parallel branch 3 and an output port 4; wherein:

the microstrip line 2 comprises an input microstrip line 21, a connecting microstrip line 22 and an output microstrip line 23 which are sequentially connected from left to right; one end of the input microstrip line 21 is connected with the input port 1, and the other end of the input microstrip line is connected with the connecting microstrip line 22; one end of the output microstrip line 23 is connected with the connecting microstrip line 22, and the other end is connected with the output port 4;

the parallel branch 3 comprises a first parallel branch 31 and a second parallel branch 32 which have the same structure and size; the first parallel branch 31 is connected with the connection part of the input microstrip line 21 and the connection microstrip line 22; the second parallel branch 32 is connected with the joint of the output microstrip line 23 and the connecting microstrip line 22;

the first parallel branch 31 includes a short-circuit transmission line 311, an open-circuit transmission line 312, a series transmission line 313, an absorption resistor 314, a half-wavelength transmission line 315, and a quarter-wavelength transmission line 316; short circuit transmission line 311 is connected in parallel with open circuit transmission line 312, then connected to series transmission line 313, connected in series with half-wavelength transmission line 315 via absorption resistor 314, and finally connected to quarter-wavelength transmission line 316.

In practice, the preferred embodiment of the present invention is as described aboveThe characteristic impedance of the microstrip line 2 is Z₄The characteristic impedance of the short-circuit transmission line 311 and the open-circuit transmission line 312 is Z₁The characteristic impedance of the series transmission line 313 is Z₂The absorption resistor 314 has a resistance value of R, and the half-wavelength transmission line 315 has a characteristic impedance of Z₂The characteristic impedance of the quarter-wave transmission line 316 is Z₃。

In specific implementation, as a preferred embodiment of the present invention, the broadband microwave circuit implements conditions of low insertion loss and flat negative group delay, as follows:

the lengths of the short-circuit transmission line 311 and the open-circuit transmission line 312 are three eighths of the wavelength corresponding to the center frequency; the electrical length θ of the short circuit transmission line 311₁₂Electrical length θ from open transmission line 312₁₁Equal;

the lengths of the serial transmission line 313 and the quarter-wavelength transmission line 316 are one quarter of the wavelength corresponding to the center frequency; the electrical length θ of the series transmission line 313₂₁And the electrical length theta of the quarter-wave transmission line 316₃Equal;

the length of half-wavelength transmission line 315 is one-half of the wavelength corresponding to the center frequency, and the electrical length of half-wavelength transmission line 315 is θ₂₂；

The lengths of the input microstrip line 21, the connecting microstrip line 22 and the output microstrip line 23 are one fourth of the wavelength corresponding to the central frequency; the input microstrip line 21, the connecting microstrip line 22 and the output microstrip line 23 have equal electrical lengths which are all theta₄。

In specific implementation, as a preferred embodiment of the present invention, the broadband microwave circuit adjusts the magnitude of the insertion loss and the flatness of the group delay by changing the characteristic impedances of the short-circuit transmission line 311, the open-circuit transmission line 312, the series transmission line 313, the half-wavelength transmission line 315, the quarter-wavelength transmission line 316, and the microstrip line 2.

In a specific implementation, as a preferred embodiment of the present invention, in the broadband microwave circuit:

the transmission coefficient is:

the group delay is:

the internal parameters were as follows:

examples

In this embodiment, a broadband microwave circuit having low insertion loss and flat negative group delay characteristics is described, and a case where the central operating frequency is 2.14GHz will be described.

As shown in fig. 2, the group delay value of the broadband microwave circuit with low insertion loss and flat negative group delay characteristics of the present invention at the center frequency of 2.14GHz is-1 ns, and the group delay is negative in the frequency range of 2.041 GHz-2.239 GHz; within the frequency range of 2.074 GHz-2.207 GHz, the fluctuation of the group delay is +/-1%, and the broadband flat negative group delay characteristic is realized.

As shown in fig. 3, experiments prove that at a frequency of 2.14GHz, the signal attenuation of the broadband microwave circuit with low insertion loss and flat negative group delay characteristics is less than 10dB, the return loss of the input/output port reaches 55.7dB, and the return loss of the input/output port is greater than 10dB in a frequency range of 2.074 GHz-2.207 GHz of the flat negative group delay, which indicates that the input/output port obtains good matching performance in a wider frequency range.

In summary, the broadband microwave circuit with low insertion loss and flat negative group delay characteristics of the present invention realizes broadband flat negative group delay characteristics, has small attenuation and delay fluctuation, has good input/output port matching, and has the characteristics of simple design method, etc., and is very suitable for various radio frequency microwave systems.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.