基于非互易移相器的有源环形器设计

Design of an Active Circulator Based on Nonreciprocal Phase Shifter

该文设计了一种采用非互易移相器实现的L波段有源环形器,在实现信号环形传输的同时满足了高隔离度的要求。根据非互易移相器在不同的传输方向会产生不同相移的原理,采用具有非互易特性的微波晶体管放大器代替传统的铁氧体材料,设计了一种将微带传输线与放大器电路并联的结构。仿真结果表明,该非互易移相器可实现正向-120°相移,反向-61°相移,与-60°相移的理想情况略有不同。将三个相同的非互易移相器首尾相连组成一个三角形结构的有源环形器,原理上可得到使信号单向环形传输的性能。对该有源环形器进行仿真,结果表明当有源环形器工作在1.8GHz时,正向传输的插入损耗接近0d B,反向传输的隔离度高于38d B。

This paper presents an active circulator based on nonreciprocal phase shifters,which enables signals to flow in only one direction and exhibits good port-to-port isolations.According to the principle that the nonre ciprocal phase shifter has different phase shifts in different transmission directions,the nonreciprocal characteristics of the microwave transistor amplifier can be used instead of ferrites.And a structure of microstrip transmission lines paralleled with an amplifier circuit is designed.Simulation results show that the phase shifter has a shift of-120° in one direction and-61° in the opposite direction,which is slightly different from the ideal case of-60°.Three identical nonreciprocal phase shifters are connected in a triangle to provide active circulator chara cteristics,with the input of one device connected to the output of the next one.This configuration enables signals to flow in only one direction.Simulation results show that when operates at 1.8 GHz,the proposed active circulator has good insertion gain of nearly 0 dB,as well as isolation,which is better than 38 dB.