Reconfigurable millimeter-wave filters using CPW-based periodic structures with novel multiple-contact MEMS switches

In this paper, fully monolithic reconfigurable millimeter-wave filters are proposed using the CPW-based periodic structures with novel multiple-contact MEMS switches. Millimeter-wave low-pass and band-pass filters were designed, fabricated, and tested. Three cascaded CPW-based periodic structures, with low-pass and band-pass intrinsic filtering characteristics, are reconfigured into a self-similar single unit cell by the operation of the novel multiple-contact MEMS switches with single actuation. By using the multiple-contact MEMS switches, the insertion loss can be reduced and the operating frequency ranges are extended to millimeter-waves with little increase of loss. Additionally, the number of the switching elements has been reduced and the bias-decoupling circuits are not required, resulting in a very small chip size. The measured results of the reconfigurable low-pass filter show the 3-dB cutoff frequency change from 67 to 28 GHz with very small change in the insertion loss from 0.32 to 0.27 dB. The center frequency of the reconfigurable band-pass filter is tuned from 55 to 20 GHz, and the measured 3-dB cutoff bandwidth changed from 32 to 12 GHz, while the average insertion loss changed from 1.27 to 1.61 dB. The chip size of the low-pass and band-pass filter including dc bias line is 1.2 mm × 1.5 mm and 1.2 mm × 4.5 mm, respectively.