30 CHz electronically steerable antennas using Ba_xSr_(1-x) TiO_3-based room-temperature phase shift6ers

摘要

We report the performance of 16-element phased array antennas operating at 30 GHzand ambient temprature. These antennas use Ba_xSr_(1-x)TiO_3(BST)-based phase shifters to produce the beams steering. Ferroelectric phase shifters offer advantages over current semiconductor and ferrite devices including faster switching speeds and lower costs. Also, ferroelectric phase shifters offer higher power handling capability than semiconductor devices and also have high radiation resistance. We made phase shifters from laser-ablated epitaxial BST films as well as from polycrystalline BST-oxide composite films. although neither the devices nor the materials themselves are fully optimized, phase s hifters have shown>360 deg of phase shift with <350V DC bias (E<9V/ #mu# m ) and approx 8 dB insertion loss. With ferroelectric phase shifters incorporated, antennas show 4radiation patterns with central-lobe half-power widths of approx 13 deg and side lobe intensities down by more than 10 dB. Using the phase shifters, the central lobe can be shifted, or "steered," by +-18 deg in either direction. These results demonstrate a first step toward a prototype steerable antenna for 20-30 GHz satellite communications as well as other applications.