Mechanical Beam Steering Reflectarray Antennas Using Focal Arc Geometries: Performance and Limitations

This paper presents a parametric study on passive, mechanically steerable reflectarray (RA) antennas using a tilted focal arc configuration. The objective is to examine the trade-offs in designing compact RA systems capable of steering beams over a wide angular range while minimizing scan losses. Multiple RA designs at 29.5 GHz are evaluated, featuring varying degrees of compactness and steering ranges with highly uniform gain across the steering range. Performance is assessed in terms of gain and aperture efficiency, highlighting the effects of focal ratio and steering range on these metrics. A prototype antenna is also manufactured and measured, validating the simulation results with a demonstrated scan loss of only 0.5 dB over a 90 -degree range and a maximum gain of 28.2 dBi. The findings provide insights into the design compromises required for passive, mechanically steerable RA systems, offering guidelines for optimizing such antennas for mm-Wave applications.