RF MEMS衰减器中功分器的优化与设计

Optimization and Design of Power Splitter in RF MEMS Attenuator

功分器是射频微机械(RF MEMS)衰减器的重要电路元件.在常用的T型结功分器基础上,设计的3种新型功分器结构对T型结的不连续结构进行了补偿,分别为半圆形功分器、漏斗形功分器和喇叭形功分器.对比3种功分器的射频性能,发现半圆形功分器的性能最优.将该功分器与悬臂梁式串联开关、π形电阻网络集成,作为衰减器的单元结构应用于RF MEMS衰减器中.利用HFSS仿真软件对该衰减器的微波性能进行模拟计算,发现采用半圆形功分器的衰减器的各项指标均优于基于T型结功分器的衰减器,尤其是消除了插入损耗曲线中16GHz附近的谐振点,提升了衰减器的性能.在DC-20GHz的频率范围内,基于半圆形功分器衰减器的插入损耗优于-2.36dB,回波损耗优于-33dB.

The power splitter is an important circuit component of the RF MEMS attenuator.Based on the commonly used T-junction splitter,three new power splitter structures are designed to compensate the discontinuous structure of the T-junction,which are semi-circular splitter,infundibuliform splitter and tubaeform splitter.Comparing the RF performance of the three power splitters,it is found that the performance of the semicircular power splitter is optimal.The power splitter is integrated with the cantilever beam series switch and theπ-shaped resistor network,and is used as the attenuator unit structure in RF.In the MEMS attenuator,the microwave performance of the attenuator is simulated by HFSS simulation software.The attenuators of the semi-circular splitter are superior to the attenuators based on the T-junction splitter,especially The resonance point near the input and output loss curve of 16 GHz is eliminated,and the performance of the attenuator is improved.In the frequency range of DC-20 Ghz,the insertion loss based on the semicircular splitter attenuator is better than-2.36 dB,and the return loss is better than-33 dB.