用于射频泄漏抑制的相位共轭电路设计

针对方向回溯天线中射频泄漏对相位共轭性能及波束指向性能影响的问题,提出了基于平衡结构的二次混频相位共轭结构,实现射频泄漏抑制。分析了传统相位共轭(phase-conjugating,PON)阵列中射频-中频(radio frequency-intermediate frequency,RF-IF)隔离度对相位共轭性能影响;并针对传统PON阵列射频泄漏抑制较差的问题,设计了基于平衡结构的阻性场效应管(field effect transistor,FET)混频电路来提高射频泄漏抑制指标和相位共轭性能;进一步设计了平衡型的二次混频相位共轭结构,利用跟踪锁相环和同相正交(in-phase/quadrature,IQ)调制结构促进RF-IF隔离。仿真结果表明,本文设计的平衡型二次混频相位共轭电路射频泄漏的抑制高于40 dB,且具有在射频输入功率低至-80 d Bm时,保持约4 dBm的稳定共轭信号输出。

Phase Conjugate Circuit Design for RF Leakage Suppression

A secondary mixing phase conjugate structure based on balanced structure is proposed to solve the problem of the influence of radio frequency(RF) leakage on phase conjugate performance and beam pointing performance in the retrodirective antenna. The influence of radio frequency-intermediate frequency(RF-IF) isolation on phase conjugate performance in traditional phase-conjugating (PON) arrays is analyzed. Aiming at the problem of poor RF leakage suppression of traditional PON arrays, a field-effect transistor (FET) mixer circuit based on balanced structure is designed to improve the RF leakage suppression index and phase conjugate performance. A balanced secondary mixing phase conjugate structure is further designed to facilitate RF-IF isolation by using a tracking phase-locked loop and an in-phase/quadrature (IQ) modulation structure. Then the simulation results are obtained that the RF leakage of the balanced secondary mixing phase conjugate circuit designed in this paper is more than 40 dB, with a stable conjugate signal output about 4 dBm when the RF input power is as low as -80 dBm.