Design And Realization On Silicon-based Mems Microwave Bandpass Filter

Filters play important roles in many RF/microwave applications,which fundamental use in wireless communication engineering is to shape signal spectrum. The rapid development of modern wireless communication technology makes radio spectrum resources scarce relatively. Emerging applications continue to challenge RF/microwave filters with ever more stringent requirement of higher performance, smaller size, lighter weight, and lower cost, which become the research hotspot of microwave filter.First, this paper summarizes the current situation of microwave filters and the research status of RF MEMS filters. Then, it is proposed the overall design of the system based on the design principle of the bandpass filter, including silicon MEMS technology, I/O port fed by CPW line, using open circuited stepped-impedance resonators(SIRs) to achieve a compact pseudo-interdigital bandpass filter. The filters which have different performance and structural parameters were analyzed and designed, and used 3D electromagnetic simulation software CST for simulation.The device structure manufacturing mask layout drawing, CMOS-MEMS compatible process for bandpass filter is designed rigorously according to related layout. Critical processes are developed such as TSV. MEMS band-pass filter chips were prepared on the high-resistivity silicon substrate after several tape-out experiments. The chip is based on a pair of 4-inch, 400μm-thick(100) n-type high resistivity silicon wafers Au-Au bonding. The through via array is formed by DRIE etching. Both top and bottom surfaces are metalized with gold for grounding.This paper presents design, simulation, fabrication, and measurement of MEMS bandpass filters. Through a comparative analysis between simulated and measured responses, verified the filter design method based on interdigital stripline structural as well as MEMS fabrication technique reliability.