CN110971211A

CN110971211A - Terahertz is 360 reflection-type phase shifters entirely now

Info

Publication number: CN110971211A
Application number: CN201811136525.2A
Authority: CN
Inventors: 马建国; 李旭光; 周绍华; 赵升; 杨自凯; 杨闯; 张蕾; 李昭
Original assignee: Tianjin University Marine Technology Research Institute
Current assignee: Tianjin University Marine Technology Research Institute
Priority date: 2018-09-28
Filing date: 2018-09-28
Publication date: 2020-04-07
Anticipated expiration: 2038-09-28
Also published as: CN110971211B

Abstract

A terahertz is full 360 degrees of reflection-type phase shifters now, through the adjustment to reflection-type phase shifter structure, promotes the insertion loss and the range performance of shifting the phase of reflection-type phase shifter, obtains the reflection-type phase shifter of full 360 degrees of phase shifting range of power consumption, insertion loss equilibrium. The phase shifter with the structure can be applied to millimeter wave/terahertz phased array systems.

Description

Terahertz is 360 reflection-type phase shifters entirely now

Technical Field

The invention belongs to the field of millimeter wave/terahertz integrated circuits, and particularly relates to a terahertz full 360-degree reflection-type phase shifter.

Background

The phased array technology has the functions of beam forming and beam scanning, so that the phased array technology has obvious advantages in systems such as communication systems and radars, the signal-to-noise ratio and the sensitivity of the system can be obviously improved, and the requirements on the power and the noise of single equipment in the system are reduced. Among them, the phase shifter is the most critical module in the phased array system, and it can change the phase of the electromagnetic wave in the link to control the propagation direction of the beam. There are various implementations of the phase shifter, which can be classified into an active type and a passive type according to whether energy is consumed or not. The active phase shifter is mainly a vector synthesis phase shifter, and a desired phase state is obtained by controlling the amplitudes of two paths of orthogonal signals and carrying out vector summation; the passive phase shifter mainly comprises a switch type phase shifter and a reflection type phase shifter, wherein the switch type phase shifter changes the phase through the on and off of different phase shifting units, and the reflection type phase shifter changes the phase of electromagnetic waves through changing the impedance of a load network.

Among these types of phase shifters, the reflection type phase shifter consumes no power and has a simple structure. With the increase of the working frequency, the area of passive devices such as inductors in the reflection-type phase shifter is reduced, and the defect of large area consumption is greatly alleviated. Therefore, the reflection-type phase shifter becomes one of the better choices of the millimeter wave terahertz phased array system. However, the phase shift range of the conventional reflection-type phase shifter is small, so that the phase shift of the whole 360 degrees is difficult to realize, and the scanning range of a phased array system is limited.

Disclosure of Invention

In order to solve the problems in the prior art, the terahertz full 360-degree reflection-type phase shifter provided by the invention has the advantages that the insertion loss and the phase shift range performance of the reflection-type phase shifter are improved by adjusting the structure of the reflection-type phase shifter, and the reflection-type phase shifter with the full 360-degree phase shift range and balanced power consumption and insertion loss is obtained. The phase shifter with the structure can be applied to millimeter wave/terahertz phased array systems.

The invention provides a terahertz full 360-degree phase shifter (as shown in figure 1) which is realized by combining a reflection-type phase shifter and a 0/180-degree phase converter based on a CMOS (complementary metal oxide semiconductor) process. Specifically, as shown in fig. 2, the single-ended input signal is converted into a differential signal by balun T1 and input to a 0 °/180 ° phase converter. The 0/180 phase converter structure is similar to a Kilbert unit structure and comprises transconductance transistors M1 and M2 and differential transistors M3-M6. The differential signal output by the T1 is input into the gates of the transconductance transistors M1 and M2, and is amplified and then output from the drains to the source of the differential transistors M3-M6. VS is used as a control signal of the differential transistor and controls the switch states of M3-M6 in cooperation with the inverter. The drains of M3-M6 are connected to transformer T2 as in the cross structure of FIG. 2 and output to the subsequent 3dB coupler input. In this process, VS, as a control signal, will produce two states, 0 ° and 180 ° when at high or low level, respectively. The reflection-type phase shifter structure consists of two parts, namely a 3dB coupler and a loaded pi-type network. The isolation end and the through end of the 3dB coupler are respectively connected with a pi-type load network consisting of C1, C2, L1, C3, C4 and L2. The C1-C4 are variable capacitors, and the capacitance value of the variable capacitors is controlled through voltage to realize impedance change of a load network and phase change of the reflection-type phase shifter. Finally, the 3dB coupler isolation terminal is the output of the whole circuit.

A terahertz is full 360 reflection-type phase shifter now, has following several advantages: first, the structure can expand the phase shift range of the traditional reflection-type phase shifter and realize the phase shift of 360 degrees. Secondly, the phase shifter in the structure can obtain balanced state change under terahertz frequency, obtain effective gain, make up loss caused by a passive structure in the phase shifter, and enable the whole phase shifter structure to have smaller insertion loss.

Drawings

FIG. 1 is a terahertz full 360 ° phase shifter structural framework;

FIG. 2 is a schematic diagram of a terahertz full 360 ° phase shifter circuit;

fig. 3 shows a conventional simple phase converter.

Detailed Description

The technical solutions of the present invention will be described in detail below with reference to the accompanying drawings, and the specific embodiments described herein are merely illustrative of the present invention, but the scope of the present invention is not limited to the embodiments.

A terahertz full 360-degree reflection-type phase shifter is shown in a structural block diagram of fig. 1, and adopts a structure of cascade connection of a 0/180-degree phase shifter and the reflection-type phase shifter, so that the full 360-degree phase shifter with low insertion loss is realized.

The detailed structure of the phase shifter is as shown in fig. 2, a terahertz signal is input to realize single-ended signal to differential conversion through a balun T1, and obtained differential signals are respectively input to gates of transconductance transistors M1 and M2 of a kirbert structure. The drains of the M1 and the M2 are connected with the sources of the differential transistors M3-M6, the M3-M6 are used as signal selection structures, the drains of the M3878 and the M3538 are connected to the transformer T2 in a crossed mode, and the inversion of a phase converter signal path is realized by controlling a level VS and an inverter. When VS is forward biased, M3 and M6 turn on, and the output state we define as 0 °; when VS is biased at 0, M4 and M5 turn on, and the output state changes to 180 °. In addition, the transconductance tubes M1 and M2 and the conducting differential tube form a cascode-like structure, and signal amplification can be obtained. When the phase converter of 0 degree/180 degree is realized, all NMOS transistors in the circuit adopt the minimum gate length size allowed by the technology to obtain the optimal transistor cut-off frequency, and adopt a multi-gate structure to improve the structure gain. The phase changer inputs the signal to the 3dB coupler through a transformer T2. The load of the coupler adopts a pi-type load network, wherein C1-C4 are variable capacitors, L1 and L2 are inductors, and the capacitance values of the variable capacitors C1-C4 are changed by controlling the change of voltage, so that the change of load impedance is realized, the phase of a reflected signal is changed, and the change of a phase-shifting range larger than 180 degrees is realized. Finally, the phase of the phase converter is continuously changed by matching 0 degree/180 degree overturn with a reflection type structure, and the phase shifting range of 360 degrees can be realized.

Claims

1. A terahertz is 360 reflection-type phase shifters entirely now, its characterized in that: based on CMOS technology, the terahertz full 360-degree phase shifter realized by combining a reflection-type phase shifter and a 0/180-degree phase converter has the following specific structure: the single-end input signal is converted into a differential signal through a balun T1 and is input into a 0/180 phase converter; the 0/180-degree phase converter structure consists of transconductance transistors M1 and M2 and differential transistors M3-M6; the differential signal output by the T1 is input into the gates of the transconductance transistors M1 and M2, and is amplified and then output from the drain to the source of the differential transistors M3-M6; VS is used as a control signal of the differential transistor and is matched with the inverter to control the switching states of M3-M6; the drains of the M3-M6 are connected to the transformer T2 in a cross structure and output to the input end of the subsequent 3dB coupler; in this process, VS is used as a control signal, and will generate two states of 0 ° and 180 ° when it is at high level or low level; the reflection-type phase shifter structure comprises a 3dB coupler and a loaded pi-type network; the isolation end and the through end of the 3dB coupler are respectively connected with a pi-type load network consisting of C1, C2, L1, C3, C4 and L2; C1-C4 are variable capacitors, and the capacitance value of the variable capacitors is controlled by voltage to realize impedance change of a load network and phase change of the reflection-type phase shifter; finally, the 3dB coupler isolation terminal is the output of the whole circuit.