Many of our devices employ SrTiO 3 as the ferroelectric. Cu 3 O 7- d to carry the microwave signals. 3 films are used in conjuction with normal metal conductors, such as gold. The first example of ferroelectric-based components is the tunable filter, which has a compact, planar design. The metallic layer consists of a thin YBa 2 Cu 3 O 7- d superconducting film.
All dimensions are in micrometers.
Extensive work has gone into developing these novel ferroelectric coupled microstrip phase shifters, which were invented at Lewis . Two configurations of these phase shifters are given in the following schematic. The ferroelectric thin film again lies below the metallic circuit on a crystal substrate. Direct-current bias is applied between the coupled microstrips, strongly affecting the dielectric constant of the ferroelectric in the gap and causing a microwave phase shift. Larger phase shifts are obtained by placing several of these coupled microstrip sections in series.