A Novel MEMS-Tunable Hairpin Line Filter on Silicon Substrate

In this paper a novel MEMS-tunable hairpin line filter is presented. The circuit has been realized on a 525 mum high resistivity silicon substrate using a well established micromachining process at ITC-IRST in Trento, Italy. The tunability of the device is obtained by line sections added to the U-line branches of the resonators of the hairpin filter through 10 identical MEMS ohmic contact cantilever switches. Measurements of the MEMS switch show an isolation and an insertion loss better than 20 dB and 0.3 dB, respectively, in the filter frequency range. Measured S-parameters of the MEMS-filter exhibit an insertion loss and a return loss better than 4.5 dB and 17 dB respectively, with a 15% passband at 6.2 GHz and 10% tuning range