Electro-Optic Devices in Dielectric Waveguide

In recent years, integrated circuit techniques have become increasingly important in implementing components and subsystems at millimeter wavelengths. One common waveguide structure in this spectral region is dielectric image line, formed by placing half-height rectangular dielectric waveguide on a metal ground plane. A number of passive and active devices have been demonstrated using image guide, including directional couplers, filters, phase shifters, scanning antennas, detectors and sources. In most cases, the active devices studied required careful mounting of a discrete electrical device in close proximity to the waveguide structure in a way which optimizes coupling to the waveguide. In this review we describe active devices in dielectric waveguide which can be realized by direct electrical control of the bulk dielectric properties of the transmission medium. These devices have intrinsic high speed, and are directly compatible with common waveguide structures.