Waveguide-based MEMS tunable filters and phase shifters

Abstract

An actively tunable waveguide-based iris filter having a first part including a first portion of a deformable iris filter cavity having an inlet and an outlet; a second part operatively coupled with the first part and including a second portion of the deformable iris filter cavity having a deformable membrane operatively coupled with the first portion of a deformable iris filter cavity; the first portion and the second portion together forming the deformable iris filter cavity of the tunable waveguide-based iris filter; and means for moving the deformable membrane, whereby movement of the deformable membrane changes the geometry of the deformable iris filter cavity for causing a change in the frequency of a signal being filtered by the filter. The tunable filter is fabricated using a MEMS-based process including a plastic micro embossing process and a gold electroplating process. Prototype filters were fabricated and measured with bandwidth of 4.05 GHz centered at 94.79 GHz with a minimum insertion loss of 2.37 dB and return loss better than 15 dB. A total of 2.59 GHz center frequency shift was achieved when membranes deflected from −50 μm to +150 μm.