Tunable ferroelectric filter-phase shifter

Abstract

Design of a tuneable filter-phase shifter is presented. Thin ferroelectric film varactors are used to provide voltage tuneable phase shift in a silicon coplanar waveguide (CPW). Varactors with zero bias capacitance 0.17pF, loss tangent tan/spl delta/-0.04 and 20% tuneability provide continuous voltage tuneable phase shift up to 90/spl deg//spl plusmn/5/spl deg/ at 19 GHz with 10% bandwidth. The figure of merit is about 30/spl deg//dB. The sizes of the phase shifter silicon chip are less than 2/spl times/5.5mm. The phase shifter is designed for possible integration in silicon MMICs.