A transmission line phase shifter includes a substrate, and first and second conductive portions adjacent the substrate with a gap therebetween. The first and second conductive portions define a signal path. A body is in the gap and includes a phase shifting material having a controllable dielectric...http://www.google.com/patents/US6421023?utm_source=gb-gplus-sharePatent US6421023 - Phase shifter and associated method for impedance matching
