CN212783739U

CN212783739U - T-type coupler-based band-pass negative group delay circuit

Info

Publication number: CN212783739U
Application number: CN202021665087.1U
Authority: CN
Inventors: 万发雨; 王燕
Original assignee: Nanjing University of Information Science and Technology
Current assignee: Nanjing Junrui Electronic Technology Co ltd
Priority date: 2020-08-12
Filing date: 2020-08-12
Publication date: 2021-03-23
Anticipated expiration: 2030-08-12

Abstract

The utility model discloses a negative crowd delay circuit of band-pass based on T type coupler, including input port and the output port, coupling microstrip line and the connecting wire that corresponds input port, coupling microstrip line includes coupling microstrip line CL1 and coupling microstrip line CL2 that the symmetry set up, coupling microstrip line CL1 and coupling microstrip line CL2 include three port at least, input port links to each other with coupling microstrip line CL 1's first port, output port links to each other with coupling microstrip line CL 2's first port, coupling microstrip line CL 1's second port links to each other with coupling microstrip line CL 2's second port, the little couplerThe third port of the strip line CL1 and the third port of the coupling microstrip line CL2 are connected with the connecting line when 2R is satisfied₀(1‑a²‑k²+a²k²)+Z(a²+k²)²When the frequency is more than 0, the band-pass negative group delay circuit realizes negative group delay, wherein a represents attenuation loss, and Z and k respectively represent characteristic impedance and coupling coefficient of the microstrip coupling line.

Description

T-type coupler-based band-pass negative group delay circuit

Technical Field

The utility model belongs to the microwave engineering field, concretely relates to negative crowd delay circuit of band-pass based on T type coupler.

Background

In the 1990 s, the NGD phenomenon was verified by circuit experiments for the first time by scholars. In the 2000 s, many scholars mainly studied NGD passive circuits formed by R, L and C lumped elements, but with large losses (-20 dB). Then, the active RLC NGD circuit solves the problem caused by insertion loss, and since 2010, more researchers have carried out more research work on the design aspects of radio frequency and microwave NGD active circuits, but the time delay of the microwave frequency band is smaller.

SUMMERY OF THE UTILITY MODEL

The purpose of the utility model is that: for the loss and the reflection that reduce negative crowd delay circuit, improve group delay, the utility model provides a negative crowd delay circuit of band-pass based on T type coupler when the great time delay is realized to the microwave frequency channel, has guaranteed the low-loss, has realized better negative crowd delay circuit performance.

The technical scheme is as follows: the utility model provides a band-pass negative group delay circuit based on T type coupler, includes input port and the output port, coupling microstrip line and the connecting wire that correspond input port, its characterized in that: the coupling microstrip line comprises a coupling microstrip line CL1 and a coupling microstrip line CL2 which are symmetrically arranged, the coupling microstrip line CL1 and the coupling microstrip line CL2 at least comprise three ports, an input port is connected with a first port of the coupling microstrip line CL1, an output port is connected with a first port of the coupling microstrip line CL2, a second port of the coupling microstrip line CL1 is connected with a second port of the coupling microstrip line CL2, a third port of the coupling microstrip line CL1 and a third port of the coupling microstrip line CL2 are both connected with a connecting line, and when the requirement of 2R is met, the coupling microstrip line CL 3578 and the coupling microstrip line CL2 are symmetrically₀(1-a²-k²+a²k²)+Z(a²+k²)²When the frequency is more than 0, the band-pass negative group delay circuit realizes negative group delay, wherein a represents attenuation loss, and Z and k respectively represent characteristic impedance and coupling coefficient of the microstrip coupling line.

Further, the coupled microstrip line CL1 and the coupled microstrip line CL2 have the same characteristic impedance.

Further, the other ports of the coupling microstrip line CL1 except the first to third ports and the other ports of the coupling microstrip line CL2 except the first to third ports are connected to matching loads.

Has the advantages that: compared with the prior art, the utility model, have following advantage:

1. the utility model can obtain a certain degree of negative group delay through the structure of the bandpass negative group delay circuit of the T-shaped coupler, and can obtain the negative group delay range and lower insertion loss required by a simulator through simple parameter adjustment;

2. the utility model has the advantages of miniaturization, low loss and reflection;

2. the utility model discloses a circuit improves group delay bandwidth and time delay greatly, and when central frequency 1.357GHz, the group delay of circuit is about-13 ns, the loss S of circuit₂₁About-9.0 dB, reflection S of the circuit₁₁About-17.7 dB.

Drawings

Fig. 1 is a schematic diagram of an NGD circuit of the present invention;

FIG. 2 is a schematic structural view of the present invention;

fig. 3 is a simulation result diagram of the NGD circuit of the present invention; wherein the content of the first and second substances,

fig. 3(a) is a schematic diagram of a group delay simulation result of the NGD circuit of the present invention;

FIG. 3(b) shows the S of the NGD circuit of the present invention₁₁A simulation result schematic diagram;

FIG. 3(c) shows the S of the NGD circuit of the present invention₂₁A simulation result schematic diagram;

fig. 4 is a schematic analysis diagram of fig. 1.

Detailed Description

The technical solution of the present invention will be further explained with reference to the accompanying drawings and examples.

Example 1:

as shown in fig. 1 and fig. 2, the bandpass negative group delay circuit based on the T-type coupler of the present embodiment has a symmetric structure, and includes two coupling microstrip lines CL1 and CL2 with the same characteristic impedance, where the coupling microstrip line CL1 has ports (i), (iii), (iv), and (v), the coupling microstrip line CL2 has ports (i), (iii), (iv), and (c), and the ports (i) and (iv) are respectively used as input and output ports of the whole circuit. In addition, Z and k in the coupled microstrip line respectively represent characteristic impedance and coupling coefficient of the microstrip coupled line, and Z is 50 Ω, a represents attenuation loss, and τ is coupling delay.

The circuit of the present embodiment is implemented on FR4 substrate using fully distributed microstrip technology. As a passive circuit, the key point of the negative group delay implementation and analysis is to calculate the S matrix model from CLs and TL. The global S matrix can be determined in different ways according to microwave circuit theory, taking into account the input and output wave power substitution and the transformation from Z to S matrix.

For better description of the circuit model, it is described in the equivalent block diagram of fig. 4. According to the S matrix theory and the TL theory, the method comprises the following steps:

wherein the content of the first and second substances,

k is the coupling coefficient.

Where x (j ω) ═ exp (-j ω τ), τ is the delay.

From the above equation:

wherein the content of the first and second substances,

wherein a is an attenuation constant;

and from the phase angle calculation formula

And a time delay calculation formula

Obtaining:

therefore, it can be obtained that when the formula 2R is satisfied₀(1-a²-k²+a²k²)+Z(a²+k²)²The delay of the circuit of fig. 1 can be negative > 0, i.e. the circuit of fig. 1 can implement a negative group delay.

The method for optimizing the simulation design of the proposed circuit by using the simulation software ADS comprises the following steps:

step 1: according to the microwave circuit theory, calculating an S matrix model through CLs and TL parameters to obtain the insertion loss S of the NGD circuit₂₁And a reflection coefficient S₁₁；

Step 2: calculating the circuit phase function according to the following formula:

and step 3: calculating the group delay function tau (omega) according to the following formula:

and 4, step 4: s for NGD circuit through ADS simulation software₁₁、S₂₁And τ (ω) were simulated and the dimensions of each electromagnetic parameter were determined after a series of optimizations of the electromagnetic parameters, as shown in table 1.

TABLE 1 NGD Circuit fundamental parameter dimensions

Fig. 3(a), (b) and (c) are respectively the group delay and S of the NGD circuit of this embodiment₁₁、S₂₁And simulating, calculating and testing a result graph, and simulating the NGD circuit at 1.3 GHz-1.4 GHz based on ADS simulation software. According to the ADS simulation diagram: at a center frequency of 1.357GHz, the group delay of the circuit is about-13 ns, and the reflection S of the circuit₁₁About-17.7 dB, the loss S of the circuit₂₁About-9.0 dB; as can be seen from fig. 3: at a center frequency of 1.345GHz, the group delay of the circuit is about-12.1 ns, and the loss S of the circuit₂₁About-8.5 dB. The calculation, simulation and test values are basically consistent, in addition, the center frequencies and time delays of the calculation, simulation and test values have slight deviation, and the calculation results mainly do not consider the time delay and loss of the connecting line TL, errors of circuit simulation and the like.

Claims

1. The utility model provides a band-pass negative group delay circuit based on T type coupler, includes input port and the output port, coupling microstrip line and the connecting wire that correspond input port, its characterized in that: the coupled microstrip line comprises a coupled microstrip line CL1 and a coupled microstrip line CL2 which are symmetrically arranged, the coupled microstrip line CL1 and the coupled microstrip line CL2 at least comprise three ports, the input port is connected with the first port of the coupled microstrip line CL1, the output port is connected with the first port of the coupled microstrip line CL2, and the coupled microstrip line CL2 is connected with the first port of the coupled microstrip line CL2The second port of the coupling microstrip line CL1 is connected with the second port of the coupling microstrip line CL2, the third port of the coupling microstrip line CL1 and the third port of the coupling microstrip line CL2 are both connected with the connecting line, and when the requirement of 2R is met₀(1-a²-k²+a²k²)+Z(a²+k²)²When the frequency is more than 0, the band-pass negative group delay circuit realizes negative group delay, wherein a represents attenuation loss, and Z and k respectively represent characteristic impedance and coupling coefficient of the microstrip coupling line.

2. The T-type coupler based bandpass negative group delay circuit of claim 1, wherein: the coupled microstrip line CL1 and the coupled microstrip line CL2 have the same characteristic impedance.

3. The T-type coupler based bandpass negative group delay circuit of claim 1, wherein: the other ports of the coupling microstrip line CL1 except the first to third ports and the other ports of the coupling microstrip line CL2 except the first to third ports are connected with matching loads.