Conformal beam steering apparatus for simultaneous manipulation of optical and radio frequency signals

摘要

A set of Risley prisms has been designed that will allow an infrared optical and radio frequency (RF) beam to be simultaneously steered through the same aperture (patent pending). Risley prisms have the advantage of allowing such beams to be steered at the skin of a vehicle such as an aircraft. By providing a mechanism for both of these bands to be steered simultaneously, substantial system size, weight, and power reductions result, making integration of these two bands onto any platform more attainable. The prisms are made of single-crystal silicon, and have special coatings applied to them that reduce surface reflections for optical signals. Additionally, an impedance matching dielectric is applied to the prisms that allow efficient transmission of RF signals. The prisms are mounted in direct drive rotary motors with position feedback resolution of 6 microradians. A set of these prisms can steer beams within a conical field of regard of 120? has a weight of about 6kg, and a size of about 175mm x 175mm x 100mm. We present some preliminary characteristics of this device, including C-band (~1550nm) optical and Ka RF (38GHz) throughput of the beams through the AR-coated and impedance-matched silicon, and an overview of Risley prism beam steering methodology.