CN112202419A - Three-frequency negative group time delay microwave circuit - Google Patents
Three-frequency negative group time delay microwave circuit Download PDFInfo
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- H03H7/30—Time-delay networks
Abstract
The embodiment of the invention discloses a three-frequency negative group time delay microwave circuit, which is characterized by comprising the following components: the device comprises an input port, a microstrip line, an output port, an absorption resistor, a matching resistor and a parallel unit; the microstrip line comprises an input microstrip line and an output microstrip line which are positioned on two sides of the matching resistor, and the input port is connected with the output microstrip line through the input microstrip line and the matching resistor and then connected with the output port to form an upper branch; the absorption resistor comprises a first absorption resistor and a second absorption resistor which are connected in series, and the input port is connected with the first absorption resistor and the parallel unit in parallel, then connected with the second absorption resistor and then connected with the output port to form a lower branch; the parallel unit is positioned between the first absorption resistor and the second absorption resistor and comprises a first transmission line, a second transmission line and a third transmission line which are connected in series. The invention can realize the negative group time delay characteristic of three frequency bands, and has the characteristics of arbitrary working frequency ratio, good impedance matching of the input and output ports and the like.
Description
Technical Field
The invention relates to the technical field of microwave circuit design, in particular to a three-frequency negative group time delay microwave circuit.
Background
Modern wireless communication is developing towards multifunction and multiband, and many radio system standards require support of multiband operation mode, which requires use of multifrequency microwave circuits to reduce size, weight and cost of the system, so that research of multifrequency negative group delay microwave circuits is of great significance. The first double-frequency negative group time delay microwave circuit is composed of a quarter-wavelength composite left-right hand transmission line, and the design is complex. An active double-frequency negative group delay circuit is generated, and the attenuation of the signal is compensated. In order to reduce the size, many researchers have proposed miniaturized circuit structures. However, these negative group delay microwave circuits can only realize dual-band characteristics and can only replace two single-band circuits. In order to meet the application requirements of a three-band system and further reduce the circuit size, a three-band negative group delay microwave circuit needs to be researched. At present, the existing three-frequency negative group delay microwave circuit is formed by simply combining three negative group delay units working at different frequencies, can not realize the same negative group delay value under the condition that the impedance of input and output ports of three frequency bands is not matched, has smaller working frequency than the realizable range, and can not cover the actual working frequency band of a radio system. In view of the above, it is necessary to provide a triple-band negative group delay microwave circuit for multi-band radio system applications.
Disclosure of Invention
Therefore, in order to overcome the defects in the prior art, the three-frequency negative group delay microwave circuit meeting the application of the multi-frequency radio system is provided.
Based on the purpose, the technical scheme of the invention is as follows:
a three-frequency negative group delay microwave circuit is characterized by comprising: the device comprises an input port, a microstrip line, an output port, an absorption resistor, a matching resistor and a parallel unit; the microstrip line comprises an input microstrip line and an output microstrip line which are positioned on two sides of the matching resistor, the input port is connected with the output microstrip line through the matching resistor by the input microstrip line and then connected with the output port to form an upper branch; the absorption resistor comprises a first absorption resistor and a second absorption resistor which are connected in series, the input port is connected with the first absorption resistor, and the input port is connected with the parallel unit in parallel, then connected with the second absorption resistor and then connected with the output port to form a lower branch; the parallel unit is positioned between the first absorption resistor and the second absorption resistor and comprises a first transmission line, a second transmission line and a third transmission line which are connected in series.
Optionally, in one embodiment, the lengths of the first transmission line, the second transmission line, and the third transmission line are all one fourth of the wavelength corresponding to the second operating frequency, and the second operating frequency is set according to actual requirements.
Optionally, in one embodiment, the length of the input microstrip line and the length of the output microstrip line are both half of the wavelength corresponding to the second operating frequency.
Optionally, in one embodiment, the transmission coefficient S of the triple-frequency negative group delay microwave circuit21The calculation formula of (2) is as follows:
the calculation formula of the group delay tau of the three-frequency negative group delay microwave circuit is as follows:
wherein, X1＝Y0(a1-a3) (3)
X2＝Y0(a2-a4) (4)
X3＝(Y0+a1)(Y0+a3)-a2a4 (5)
X4＝a2(Y0+a3)+a4(Y0+a1) (6)
X′1＝Y0(a′1-a′3) (7)
X′2＝Y0(a′2-a′4) (8)
X′3＝Y0(a′1+a′3)+a′1a3+a1a′3-a′2a4-a2a′4 (9)
X′4＝Y0(a′2+a′4)+a′2a3+a2a′3+a′1a4+a1a′4 (10)
Z′in＝z1(P-Q)/[z1(z2+z3cot(θ3)tan(θ2))+z2(z3cot(θ3)-z2tan(θ2))tan(θ1)]2(20)
Wherein z is1、τ1And theta1Characteristic impedance, group delay value and electrical length, z, of the first transmission line, respectively2、τ2And theta2Characteristic impedance, group delay value and electrical length, z, of the second transmission line, respectively3、τ3And theta3Characteristic impedance, group delay value and electrical length, r, of the third transmission line, respectively1To absorb the resistance value of the resistor, z4、τ4And theta4Characteristic impedance, group delay value and electrical length, r, of the microstrip line, respectively2To match the resistance value of the resistor, Y0Is the port admittance.
The embodiment of the invention has the following beneficial effects:
the invention provides a triple-frequency negative group delay microwave circuit meeting the application of a multi-frequency radio system, which solves the problem that the prior art cannot simultaneously realize input and output impedance matching and cannot randomly change the working frequency ratio, can realize the negative group delay characteristic of a triple frequency band, has the characteristics of random working frequency ratio, good impedance matching of an input port and an output port and the like, can achieve the achievable range of the ratio of a third working frequency to a first working frequency to be 3.4-11.2 under the condition that a second working frequency is determined, and can achieve the echo loss in each negative group delay frequency band to be more than 12 dB.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Wherein:
FIG. 1 is a schematic diagram of a three-frequency negative group delay microwave circuit according to the present invention;
FIG. 2 is a group delay plot of a three-frequency negative group delay microwave circuit according to the present invention;
FIG. 3 is a S parameter curve diagram of a three-frequency negative group delay microwave circuit according to the present invention;
in the figure: 1. the parallel unit comprises a parallel unit 11, a first transmission line 12, a second transmission line 13, a third transmission line 2, an absorption resistor 21, a first absorption resistor 22, a second absorption resistor 3, a microstrip line 31, an input microstrip line 32, an output microstrip line 4, a matching resistor 5, an input port 6 and an output port.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. It will be understood that, as used herein, the terms "first," "second," and the like may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the present application. The first and second elements are both elements, but they are not the same element.
In this embodiment, a triple-frequency negative group delay microwave circuit is specifically proposed, as shown in fig. 1, and is characterized by including: the device comprises an input port 5, a microstrip line 3, an output port 6, an absorption resistor 2, a matching resistor 4 and a parallel unit 1; the microstrip line 3 comprises an input microstrip line 31 and an output microstrip line 32 which are positioned on two sides of the matching resistor 4, the input port 5 is connected with the output microstrip line 32 through the input microstrip line 31 via the matching resistor 4, and then is connected with the output port 6 to form an upper branch; the absorption resistor 2 comprises a first absorption resistor 21 and a second absorption resistor 22 which are connected in series, the input port 5 is connected with the first absorption resistor 21 and the parallel unit 1 in parallel, then is connected with the second absorption resistor 22, and then is connected with the output port 6 to form a lower branch; the parallel unit 1 is located between the first absorption resistor 21 and the second absorption resistor 22, and includes a first transmission line 11, a second transmission line 12, and a third transmission line 13 connected in series.
In one embodiment, the lengths of the first transmission line 11, the second transmission line 12 and the third transmission line 13 are all one fourth of the wavelength corresponding to the second operating frequency, and the second operating frequency is set according to actual requirements.
In one embodiment, the lengths of the input microstrip line 31 and the output microstrip line 32 are both half of the wavelength corresponding to the second operating frequency.
In one of which is implementedIn one embodiment, the transmission coefficient S of the triple-frequency negative group delay microwave circuit21The calculation formula of (2) is as follows:
the calculation formula of the group delay tau of the three-frequency negative group delay microwave circuit is as follows:
wherein, X1＝Y0(a1-a3) (3)
X2＝Y0(a2-a4) (4)
X3＝(Y0+a1)(Y0+a3)-a2a4 (5)
X4＝a2(Y0+a3)+a4(Y0+a1) (6)
X′1＝Y0(a′1-a′3) (7)
X′2＝Y0(a′2-a′4) (8)
X′3＝Y0(a′1+a′3)+a′1a3+a1a′3-a′2a4-a2a′4 (9)
X′4＝Y0(a′2+a′4)+a′2a3+a2a′3+a′1a4+a1a′4 (10)
Z′in＝z1(P-Q)/[z1(z2+z3cot(θ3)tan(θ2))+z2(z3cot(θ3)-z2tan(θ2))tan(θ1)]2(20)
Wherein z is1、τ1And theta1Characteristic impedance, group delay value and electrical length, z, of the first transmission line 11, respectively2、τ2And theta2Characteristic impedance, group delay value and electrical length, z, of the second transmission line 12, respectively3、τ3And theta3Characteristic impedance, group delay value and electrical length r of the third transmission line 13, respectively1To absorb the resistance value of the resistor 2, z4、τ4And theta4Characteristic impedance, group delay value and electrical length r of the microstrip line 3, respectively2To match the resistance value of the resistor 4, Y0Is the port admittance.
Therefore, although the first working frequency, the second working frequency and the third working frequency are given according to actual requirements in the initial design, that is, three working frequencies are known, based on the design scheme, firstly, the length of each transmission line is determined according to the second working frequency, then, the characteristic impedance of each transmission line is adjusted, and the first working frequency and the third working frequency are moved to the required working frequencies, so that the circuit can work at the required three frequencies; meanwhile, the circuit structure corresponding to the scheme can adjust the working frequency ratio according to actual requirements, namely when the second working frequency is not changed, the first working frequency and the third working frequency are changed by adjusting the characteristic impedance of each transmission line, so that the working frequency ratio can be adjusted at will under the condition of ensuring good impedance matching of the input and output ports, and the working requirements of more various three-frequency systems are met.
For example, the present embodiment can reduce the first operating frequency of the present circuit and increase the third operating frequency by increasing the characteristic impedance of the first transmission line 11 and the second transmission line 12 and reducing the characteristic impedance of the third transmission line 13; meanwhile, the negative group delay values at the first operating frequency and the third operating frequency can be increased by increasing the characteristic impedance of the microstrip line 3. And when the second working frequency is given, the ratio of the third working frequency to the first working frequency of the circuit can be realized within the range of 3.4-11.2.
In order to further explain the triple-frequency negative group delay microwave circuit provided by the present invention, a specific example implemented on the premise of the technical scheme of the present invention is described in detail below, but the protection scope of the present invention is not limited to the following examples, and the methods used in the following examples are conventional methods unless otherwise specified.
Specific example (1): this example illustrates the case of the triple-frequency negative group delay microwave circuit meeting the application of the multi-frequency radio system when the first operating frequency is 1.2GHz, the second operating frequency is 3.5GHz, and the third operating frequency is 5.8 GHz.
As shown in FIG. 2, experiments prove that the group delay value at the first working frequency of 1.2GHz is-1.08 ns, the group delay value at the second working frequency of 3.5GHz is-1.19 ns, and the group delay value at the third working frequency of 5.8GHz is-1.09 ns, so that the triple-frequency negative group delay characteristic is realized. As shown in fig. 3, experiments prove that at a frequency of 1.2GHz, the signal attenuation of the tri-band negative group delay microwave circuit of the present invention is 16.38dB, the return loss of the input/output port reaches 16.09dB, and the return loss of the input/output port is greater than 12.1dB in a frequency range of 1.102GHz to 1.251GHz, which indicates that the input/output port obtains good matching performance in the first negative group delay operating frequency range; at the frequency of 3.5GHz, the signal attenuation of the three-frequency negative group delay microwave circuit is 24.58dB, the return loss of an input/output port reaches 17.6dB, and the return loss of the input/output port is more than 14.7dB in the frequency range of 3.351 GHz-3.652 GHz, which indicates that the input/output port also obtains good matching performance in the second negative group delay working frequency range; at the frequency of 5.8GHz, the signal attenuation of the novel triple-frequency negative group time delay microwave circuit is 18.9dB, the return loss of the input/output port reaches 16.4dB, and the return loss of the input/output port is more than 13.2dB in the frequency range of 5.694 GHz-5.902 GHz, which shows that the input/output port still obtains good matching performance in the working frequency range of the third negative group time delay.
In summary, the triple-frequency negative group delay microwave circuit provided by the invention realizes the triple-frequency negative group delay characteristic, the impedance matching of the input and output ports is good within the working frequency range of the triple-negative group delay, and meanwhile, the method for designing the circuit is characterized by simplicity, practicability and the like, and is very suitable for the application of a multi-frequency radio system.
The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present application. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (4)
1. A three-frequency negative group delay microwave circuit is characterized by comprising: the device comprises an input port (5), a microstrip line (3), an output port (6), an absorption resistor (2), a matching resistor (4) and a parallel unit (1); the microstrip line (3) comprises an input microstrip line (31) and an output microstrip line (32) which are positioned on two sides of the matching resistor (4), the input port (5) is connected with the output microstrip line (32) through the input microstrip line (31) via the matching resistor (4), and then is connected with the output port (6) to form an upper branch; the absorption resistor (2) comprises a first absorption resistor (21) and a second absorption resistor (22) which are connected in series, the input port (5) is connected with the first absorption resistor (21), and the input port is connected with the second absorption resistor (22) after being connected with the parallel unit (1) in parallel and then is connected with the output port (6) to form a lower branch; the parallel unit (1) is positioned between a first absorption resistor (21) and a second absorption resistor (22) and comprises a first transmission line (11), a second transmission line (12) and a third transmission line (13) which are connected in series.
2. A triple-band negative group delay microwave circuit according to claim 1, wherein the lengths of the first transmission line (11), the second transmission line (12) and the third transmission line (13) are all one quarter of the wavelength corresponding to the second operating frequency, and the second operating frequency is set according to the actual requirement.
3. A triple-band negative group delay microwave circuit according to claim 1 or 2, wherein the length of the input microstrip line (31) and the length of the output microstrip line (32) are both half of the wavelength corresponding to the second operating frequency.
4. The triple-band negative group delay microwave circuit of claim 1, wherein the transmission coefficient S of the triple-band negative group delay microwave circuit21The calculation formula of (2) is as follows:
the calculation formula of the group delay tau of the three-frequency negative group delay microwave circuit is as follows:
wherein, X1＝Y0(a1-a3) (3)
X2＝Y0(a2-a4) (4)
X3＝(Y0+a1)(Y0+a3)-a2a4 (5)
X4＝a2(Y0+a3)+a4(Y0+a1) (6)
X′1＝Y0(a′1-a′3) (7)
X′2＝Y0(a′2-a′4) (8)
X′3＝Y0(a′1+a′3)+a′1a3+a1a′3-a′2a4-a2a′4 (9)
X′4＝Y0(a′2+a′4)+a′2a3+a2a′3+a′1a4+a1a′4 (10)
Z′in＝z1(P-Q)/[z1(z2+z3cot(θ3)tan(θ2))+z2(z3cot(θ3)-z2tan(θ2))tan(θ1)]2 (20)
Wherein z is1、τ1And theta1Respectively the characteristic impedance, the group delay value and the electrical length, z, of the first transmission line (11)2、τ2And theta2Respectively the characteristic impedance, the group delay value and the electrical length, z, of the second transmission line (12)3、τ3And theta3Respectively the characteristic impedance, the group delay value and the electrical length, r, of the third transmission line (13)1Is a resistance value of the absorption resistor (2), z4、τ4And theta4Respectively the characteristic impedance, the group delay value and the electrical length r of the microstrip line (3)2To match the resistance value of the resistor (4), Y0Is the port admittance.
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| CN113328717A (en) * | 2021-05-07 | 2021-08-31 | 大连海事大学 | Double-frequency low-insertion-loss negative group delay microwave circuit based on three-conductor asymmetric coupling line |
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