Tunable, micromachined parallel-plate transmission lines

Abstract

We have fabricated for the first time cantilevered, tunable, out of the plane transmission lines and demonstrated the active change of impedance levels using banks of finger capacitors as motors. The tunable lines are fabricated in a coplanar waveguide-like configuration thereby making them compatible with existing monolithic millimeter wave devices. The architecture can be readily applied to make variable matching circuits for antennas, and cascading several in series, variable length stubs. The process provides enough flexibility for design variations and future enhancements, for instance, n-switching devices, filters and phase array antennas. This novel device is simple, monolithic, does not require any high temperature steps, and can therefore, be readily incorporated to other processes.