Design of reconfigurable fractal antennas and RF-MEMS for space-based systems

Abstract

In this paper, design concepts of reconfigurable and electronically steered antennas based on a new fractal antenna and RF-MEMS devices are presented. As modern telecommunications extend towards higher frequencies, the advantages of employing RF-MEMS switches, phase shifters, and miniaturized fractal antennas become more significant. The input characteristics of the Hilbert curve fractal antenna can be made frequency agile by incorporating RF switches along its length. In addition, due to the large number of connected segments in this antenna geometry, reconfigurable radiation characteristics can be obtained by adding just a few additional line segments to interconnect these through semiconductor or RF-MEMS switches. The beam peak direction can be shifted by 63° and the beam width can be changed by up to 25° by this approach. An electronically steered antenna with micromachined phase shifters using tunable ferroelectric barium strontium titanate thin film is also discussed. These MEMS-based antenna systems find applications in communications satellites and electronically scanned arrays for space-based radars.