Distributed phase shifter with pyrochlore bismuth zinc niobate thin films

A monolithic Ku-band phase shifter employing voltage tunable Bi1.5Zn1.0Nb1.5O7 (BZN) thin film parallel plate capacitors is reported. BZN films were deposited by radio frequency magnetron sputtering on single-crystal sapphire substrates. A nine-section distributed coplanar waveguide loaded-line phase-shifter structure was designed. A differential phase shift of 175 degrees was achieved with a maximum insertion loss of 3.5 dB; at 15 GHz, giving a figure of merit similar to 50 degrees/dB. To the best of our knowledge, this is the first demonstration of a monolithic tunable microwave circuit using BZN thin films.