DGS Structure Applied In Reconfigurable MEMS Filter

Reconfigurable filter is a critical device in the radar and modern multi-band communication system. MEMS reconfigurable filter enable the construction of reconfigurable filter that exhibit low power consumption, low insertion loss, high isolation and linearity, miniature size, and easy for miniaturization and integration of communication components compared to the traditional reconfigurable filter. Integration of MEMS reconfigurable filter in radar communication system can reduce overall system size, weight and improve the speed of signal processing. So the MEMS reconfigurable filter become more and more widespread concerned.Defected Ground Structure (DGS) is extended from Electromagnetic Band Gap (EBG), which has the characteristics to suppress the propagation of electromagnetic waves of a specified frequency band. It has obvious characteristics of the forbidden band and slow wave. The MEMS reconfigurable filter based on DGS is designed, which has small size, low insertion loss and high band rejection.These works are presented in this thesis:1. Analysis the DGS structure, on the basis of the structure, MEMS reconfigurable low-pass is proposed, simulate the structure and extract the equivalent circuit model, analysis the effect of structure parameters to the MEMS reconfigurable low-pass filter.2. The MEMS capacitors is loaded to reconfigure the low pass filter based on DGS structure, the cut-off frequency is 16.19GHz and 19.71GHz, the insertion loss is lower than 1.18dB, the band attenuation is up to 40dB.3. MEMS reconfigurable filter are fabricated use surface micromachining, some important technologies is modified according to the actual requirement. The slow-wave characteristics of DGS and small size characteristics of MEMS reduce the size reconfigurable filter greatly, the size of the MEMS reconfigurable filter is 4.1mmX 1.4mm.4. The result show excellent characteristics of the filter, which prove that the design of the MEMS reconfigurable filter is reasonable, the process is feasible.The paper presents theory base and circuit design examples to novel Radar systems and MIC with high performance, small size, low power loss, and novel periodic structure (DGS).