X波段宽带数控移相器180°移相单元的设计

Design of 180°Phase Shift Unit of X-Band Logic Control Phase Shifter

基于0.25μm GaAs pHEMT工艺,设计出一种应用于X波段宽带数控移相器的180°移相单元。该设计采用SPDT开关和五阶高通-低通滤波拓扑结构,通过改进SPDT开关、提升滤波器的阶数和改变180°移相单元的切换方式改善电路的插入损耗和相位平坦度,消除由前32个相位产生的相位累积误差。仿真结果表明,180°移相单元插入损耗为2.42~2.67 dB,相移范围为179°~182°,输入输出电压驻波比小于1.15,在同样的结构下,本设计可实现更优异的性能和更紧凑的芯片面积。

Based on 0.25μm GaAs pHEMT process,a 180°phase shifter is designed for Xband logic control phase shifters,using SPDT switch and fifth order highpass/lowpass filter topology.By adding the order of the filter and changing the switching mode of the 180°phase shifter unit,the insertion loss and phase flatness of the circuit is improved,and the phase accumulation error caused by the first 32 phases eliminated.Simulation tests show that the insertion loss of 180°phase shift unit is 2.42-2.67 dB,the phase shift range is 179°-182°,and the inputoutput voltage outstanding wave ratio is less than 1.15,indicating thatthe design can achieve better performance and more compact chip area under the same topology.