阅读说明：本技术 一种Ti型低损耗负群时延电路及设计方法 (Ti type low-loss negative group delay circuit and design method ) 是由 万发雨 徐业翔 李宁东 于 2020-05-26 设计创作，主要内容包括：本发明包括一种Ti型低损耗负群时延电路及设计方法,包括T型连接器,所述T型连接器一端连接第一微带线TL<Sub>1</Sub>,T型连接器Tee另一端连接第二微带线TL<Sub>2</Sub>,T型连接器下方连接第三微带线TL<Sub>3</Sub>,所述第三微带线TL<Sub>3</Sub>的下方连接耦合微带线CL；端口1、端口2分别为整个电路的输入、输出端口。本发明能够降低电路的损耗和反射,提高群时延,本发明还对负群时延电路进行了优化设计,最终可得：该NGD电路工作于S频段,在中心频率为2.2GHz时,电路的群时延为-1.2ns,电路的插入损耗S<Sub>21</Sub>为-2.1dB,电路的反射系数S<Sub>11</Sub>为-12dB。(The invention comprises a Ti type low-loss negative group delay circuit and a design method, wherein the Ti type low-loss negative group delay circuit comprises a T-shaped connector, one end of the T-shaped connector is connected with a first microstrip line TL 1 The other end of the T-shaped connector Tee is connected with a second microstrip line TL 2 A third microstrip line TL is connected below the T-shaped connector 3 The third microstrip line TL 3 The lower part of the coupling microstrip line CL is connected; the port 1 and the port 2 are input and output ports of the whole circuit respectively. The invention can reduce the loss and reflection of the circuit and improve the group delay, and the invention also carries out the optimized design of the negative group delay circuit, and finally obtains: the NGD circuit works in S frequency band, when the central frequency is 2.2GHz, the group delay of the circuit is-1.2 ns, and the insertion loss S of the circuit 21 Is-2.1 dB, the reflection coefficient S of the circuit 11 Is-12 dB.)

1. A Ti type low-loss negative group delay circuit is characterized in that: comprises a T-shaped connector, one end of the T-shaped connector is connected with a first microstrip line TL₁The other end of the T-shaped connector Tee is connected with a second microstrip line TL₂A third microstrip line TL is connected below the T-shaped connector₃The third microstrip line TL₃The lower part of the coupling microstrip line CL is connected; the port 1 and the port 2 are input and output ports of the whole circuit respectively.

2. The Ti-type low-loss negative group delay circuit of claim 1, wherein: when the center frequency of the negative group delay circuit is 2.2GHz, the group delay of the circuit is-1.2 ns, and the circuitInsertion loss S of₂₁Is-2.1 dB, the reflection coefficient S of the circuit₁₁Is-12 dB.

3. A method for designing a Ti-type low-loss negative group delay circuit according to claim 1, comprising the steps of:

(1) calculating S parameter matrixes of the T-shaped connector Tee and the coupling microstrip line CL;

(2) an S parameter matrix of the whole negative group delay circuit is derived according to a normalized incident voltage wave and a reflected voltage wave which are defined by the S parameter;

(3) calculating the insertion loss of the negative group delay circuit

(4) By the formulaTo find the transmission phase function of the circuitDefined again by group delayTo find the group delay function tau (omega);

(5) for negative group delay circuit by ADS simulation software

4. The method of claim 3, wherein the Ti-type low-loss negative group delay circuit comprises: in step (1), according to the microwave circuit principleTheoretical calculation of the S parameter matrix [ S ] of the T-shaped connector Tee^PWD]The calculation formula is as follows:

5. the method of claim 3, wherein the Ti-type low-loss negative group delay circuit comprises: in the step (1), an S parameter matrix of the coupling microstrip line CL is calculated according to the microwave circuit theoryThe calculation formula is as follows:

in the formula (I), the compound is shown in the specification,a represents attenuation loss, ξ represents the coupling coefficient of the coupled microstrip line, s represents the spacing of the coupled microstrip line CL, τ represents time delay,

6. the method of claim 3, wherein the Ti-type low-loss negative group delay circuit comprises: in step (2), the S parameter matrix of the whole negative group delay circuit

7. the design method of Ti-type low-loss negative group delay circuit as claimed in claim 3The method is characterized in that: in the step (3), the reflection coefficient of the negative group delay circuitAnd insertion loss

wherein the content of the first and second substances,

ξ represents the coupling coefficient of the coupling microstrip line, s represents the distance between the coupling microstrip line CL;

8. The method of claim 3, wherein the Ti-type low-loss negative group delay circuit comprises: in the step (5), the simulation model adopts an FR4 board, the thickness of the board is 1.6mm, the dielectric constant is 5.1, the tangent loss angle is 0.02, and the copper thickness is 0.035 mm.

Technical Field

The invention belongs to the microwave engineering technology, and particularly relates to a Ti-type low-loss negative group delay circuit and a design method thereof.

Background

Time delay is a key limiting factor for the rapid development of radio frequency and microwave communication systems. The negative group delay circuit may be used to equalize the delay of radio frequency and microwave communication systems. The negative group delay circuit is a microwave circuit which utilizes the dispersion effect to realize that the output pulse peak value leads the input pulse peak value. The circuit has wide application value, such as application to array antennas for solving the beam tilt problem, application to the enhancement effect of a high-power feed-forward amplifier, application to a filter for realizing the equalization of time delay, and application to the problems of signal attenuation caused by long-distance transmission of radio frequency signals and signal distortion caused by time delay. The attenuation of the negative group delay occurs at its maximum, so loss is an important issue to be solved by the negative group delay circuit. The initial negative group delay circuit is made up of RLC lumped elements with losses greater than 20 dB. In order to solve the problem of loss, a student adopts an active circuit to realize a lossless negative group delay circuit, but the circuit cannot be applied to the field of radio frequency microwaves, and recently, the student adopts a microstrip structure to realize the negative group delay circuit, but the loss is more than-10 dB, the structure is complex, and the network analysis and the comprehensive work are difficult to carry out theoretically.

Disclosure of Invention

The purpose of the invention is as follows: the first purpose of the invention is to provide a Ti type low-loss negative group delay circuit which can reduce the loss and reflection of the negative group delay circuit and improve the group delay; a second object of the present invention is to provide a method for designing a Ti-type low-loss negative group delay circuit, which can optimize the negative group delay circuit.

The technical scheme is as follows: the microstrip line connector comprises a T-shaped connector, wherein one end of the T-shaped connector is connected with a first microstrip line TL₁The other end of the T-shaped connector Tee is connected with a second microstrip line TL₂A third microstrip line TL is connected below the T-shaped connector₃Third microstrip line TL₃The lower part of the coupling microstrip line CL is connected; the port 1 and the port 2 are input and output ports of the whole circuit respectively.

When the center frequency of the negative group delay circuit is 2.2GHz, the group delay of the circuit is-1.2 ns, and the insertion loss S of the circuit₂₁Is-2.1 dB, the reflection coefficient S of the circuit₁₁Is-12 dB.

The invention also comprises a design method of the Ti type low-loss negative group delay circuit, which comprises the following steps:

(1) calculating S parameter matrixes of the T-shaped connector Tee and the coupling microstrip line CL;

(2) an S parameter matrix of the whole negative group delay circuit is derived according to a normalized incident voltage wave and a reflected voltage wave which are defined by the S parameter;

(3) calculating negative groupInsertion loss of time delay circuit

And coefficient of reflection

(4) By the formula

To find the transmission phase function of the circuitDefined again by group delay

To find the group delay function tau (omega);

(5) for negative group delay circuit by ADS simulation softwareAnd tau (omega) performing simulation, and determining the size of basic parameters of the negative group delay circuit after electromagnetic parameter optimization.

In the step (1), an S parameter matrix of the coupling microstrip line CL is calculated according to the microwave circuit theoryThe calculation formula is as follows:

in the formula (I), the compound is shown in the specification,

a represents attenuation loss, ξ represents the coupling coefficient of the coupled microstrip line, s represents the spacing of the coupled microstrip line CL, τ represents time delay,

in step (2), the S parameter matrix of the whole negative group delay circuit

The expression of (a) is:

in the step (3), the reflection coefficient of the negative group delay circuitAnd insertion loss

The calculation formula is as follows:

wherein the content of the first and second substances,

ξ represents the coupling coefficient of the coupling microstrip line, s represents the distance between the coupling microstrip lines CL;x(s) represents a laplace transform, where s ═ jw, and d(s) represents an intermediate parameter.

In the step (5), the simulation model adopts an FR4 board, the thickness of the board is 1.6mm, the dielectric constant is 5.1, the tangent loss angle is 0.02, and the copper thickness is 0.035 mm.

Has the advantages that: compared with the prior art, the invention has the beneficial effects that: (1) the loss and reflection of the negative group delay circuit are reduced, and the group delay is improved; (2) design of the inventionThe method optimizes the negative group delay circuit, and finally the following results are obtained: the NGD circuit works in S frequency band, when the central frequency is 2.2GHz, the group delay of the circuit is-1.2 ns, and the insertion loss S of the circuit₂₁Is-2.1 dB, the reflection coefficient S of the circuit₁₁Is-12 dB.

Drawings

FIG. 1 is a schematic circuit diagram of a Ti-type low-loss negative group delay circuit according to the present invention;

FIG. 2 is a schematic diagram of an equivalent circuit of FIG. 1;

FIG. 3 is a diagram of an ADS model of the Ti-type low-loss negative group delay circuit according to the present invention;

FIG. 4 is a schematic diagram of a group delay simulation result of the Ti-type low-loss negative group delay circuit according to the present invention;

FIG. 5 is S of the design method of negative group delay circuit according to the present invention₂₁A simulation result schematic diagram;

FIG. 6 is S of the negative group delay circuit design method of the present invention₁₁And (5) a simulation result schematic diagram.

Detailed Description

The invention is described in further detail below with reference to specific embodiments and the attached drawings.

As shown in fig. 1, the negative group delay circuit of the present invention includes a T-shaped connector, one end of which is connected to a first microstrip line TL₁The other end of the T-shaped connector Tee is connected with a second microstrip line TL₂A third microstrip line TL is connected below the T-shaped connector₃Third microstrip line TL₃The lower part of the coupling microstrip line CL is connected; the port 1 and the port 2 are input and output ports of the whole circuit respectively.

The invention also comprises a design method of the Ti type low-loss negative group delay circuit, which comprises the following steps:

(1) calculating S parameter matrixes of the T-shaped connector Tee and the coupling microstrip line CL;

(2) an S parameter matrix of the whole negative group delay circuit is derived according to a normalized incident voltage wave and a reflected voltage wave which are defined by the S parameter;

(3) calculating the insertion loss of the negative group delay circuit

And coefficient of reflection

(4) By the formulaTo find the transmission phase function of the circuit

Defined again by group delay

To find the group delay function tau (omega);

(5) for negative group delay circuit by ADS simulation softwareAnd tau (omega) performing simulation, and determining the size of basic parameters of the negative group delay circuit after electromagnetic parameter optimization.

As shown in fig. 2, according to the S-parameter theory, an equivalent S-parameter matrix of an ideal T-connector Tee is given:

further, the input/output wave power a through the T-shaped connector Tee_mAnd b_mThe relationship between (m ═ {1,2,3}) can be expressed by the following equation:

as shown in fig. 2, the coupling microstrip line CL presents a four-port network with port numbers 3,4,5 and 6, respectively. Let ζ denote the coupling coefficient of the coupled line, we can assume that:

therefore, according to the S-parameter theory of the coupled lines, an S-parameter matrix of the coupled lines can be obtained:

in the formula (I), the compound is shown in the specification,

a represents attenuation loss, ξ represents the coupling coefficient of the coupled microstrip line, s represents the spacing of the coupled microstrip line CL, τ represents time delay,

wherein the content of the first and second substances,

wherein the content of the first and second substances,

the AND wave port a_mAnd b_mThe relevant four-dimensional S-matrix (m ═ {3,4,5,6}) can be represented by the relationship:

the negative group delay circuit proposed by the present application is a two-port network, and therefore, the S parameter matrix of the whole circuit can be expressed as:

from equations (1) - (8), the following expression can be obtained:

therefore, the reflection coefficient and transmission coefficient of the circuit can be obtained:

wherein:

ξ represents the coupling coefficient of the coupling microstrip line, s represents the distance between the coupling microstrip lines CL;

x(s) represents a laplace transform, where s ═ jw, and d(s) represents an intermediate parameter.

Let the angular frequency variable ω take s ═ j ω. For frequency domain analysis, we will use the amplitudes of the reflection and transmission coefficients:

S₁₁(jω)＝S₁₁(s) (13)

S₂₁(jω)＝S₂₁(s) (14)

the transmission phase is:

the group delay expression is:

therefore, according to equation (16), the group delay of the whole circuit can be obtained.

TABLE 1 physical and geometric parameters of TI prototype

As shown in FIG. 3, the ADS model used FR4 board having a thickness of 1.6mm, dimensions of 24mm by 46mm, a dielectric constant of 5.1, a tangent loss angle of 0.02, and a copper thickness of 0.035 mm. Simulation design optimization is carried out on the proposed circuit by using simulation software ADS, and the basic parameter size of the NGD circuit shown in the table 1 can be obtained.

As shown in FIGS. 4 to 6, the NGD circuit is simulated at 2.1 to 2.3GHz based on ADS simulation software. According to the ADS simulation diagram: the NGD circuit works in S frequency band, when the central frequency is 2.21GHz, the group delay of the circuit is-1.2 ns, and the insertion loss S of the circuit₂₁Is-2.3 dB, the reflection S of the circuit₁₁About-11.5 dB; according to the calculation schematic diagram: the NGD circuit works in S frequency band, when the central frequency is 2.2GHz, the group delay of the circuit is-2.3 ns, and the insertion loss S of the circuit₂₁Is-1.6 dB, the reflection S of the circuit₁₁About-15.7 dB. The calculation is substantially consistent with the simulation value. The errors are mainly caused by the fact that an ideal Tee model and a coupler model are considered by a calculation model, the calculation model is slightly different from an actual circuit model, and in addition, circuit simulation has errors.