片上集成MEMS射频滤波器

研究采用MEMS工艺技术制造可在硅集成电路片上集成的射频滤波器.MEMS工艺技术实现了高性能嵌入式螺管电感和金属-绝缘层-金属电容元件的集成制造.整个微加工制造工艺为低温工艺,可与CMOS集成电路工艺实现后端集成.基于此工艺,设计和实现了应用于5 GHz射频频段的微小化的片上集成滤波器,包括一种低通滤波器和一种带通滤波器.测试结果表明,5阶低通滤波器的 -1.5 dB 转折频率在5.3 GHz频率,从直流到5 GHz频率的插入损耗小于1.06 dB.实现的带通滤波器为两阶谐振耦合式,在中心频段5.3 GHz的最小插入损耗为4.3 dB,通带内的回波损耗大于13 dB.研究结果表明:该微加工技术适用于无源器件和滤波器电路的CMOS后端集成,适合高性能射频片上系统的应用.

On-chip Integrated MEMS-based RF Filters

This paper presented a post-CMOS compatible micromachining process for implementation of compact-sized on-chip integrated RF filters.The micromachining process achieves simultaneous formation of high performance concave solenoid inductors and metal-insulator-metal (MIM) capacitors.The fabrication process is in low temperature condition and suitable for post process of CMOS integrated circuits.Based on this process,compact-sized RF filters for 5 GHz band are designed and fabricated,including a lowpass type and a bandpass type.From the measured results,the 5th order lowpass filter has -1.5 dB cut-off frequency at 5.3 GHz and shows insertion loss of less than 1.06 dB up to 5 GHz.The bandpass filter implemented is a 2nd order coupled-resonator type.The measured minim um insertion loss is 4.3 dB at passband around 5.3 GHz,and the return loss is better than 13 dB in the designed passband.The results show that the developed micromachining technology is suitable for post-CMOS integration of RF passive devices and filter circuits.This technology is promising for implementation of radio-frequency system-on-a-chip (RF-SoC).