Tunable low-pass Ka-band MEMS filter based on Electromagnetic-Bandgap Structure

A low-pass Ka-band MEMS tunable filter based on the high-resistivity silicon substrate with Electromagnetic-Bandgap Structure (EBG) is presented. The tunable filter consists of multiple MEMS switches fabricated by a CMOS-compatible surface micromachining process. The equivalent circuit model of the tunable EBG bandstop filter was derived based on the circuit analysis theory. The dispersion characteristics obtained are useful for describing and understanding the propagation characteristics of the EBG and the MEMS bridges. The performance of the single MEMS bridges is discussed. The measurement results of the tunable MEMS filter showsa 3-dB cutoff frequency tunable from 34.25 GHz to 26.60 GHz, while the average insertion loss varies from 0.25 dB to 0.22 dB. The whole chip size is 3.6 mm × 1.6 mm. This work demonstrates a high-performance miniaturized tunable low-pass filters at mm-waves frequency bands using Electromagnetic-Bandgap Structure.