Off-the-shelf Optical Antenna Feed System

An optical antenna feed system reduces or eliminates conducting feed cable effects and provides much more accurate antenna far-field pattern measurements. Optical feed systems can be expensive and require custom design. We present a simple optical feed system for antenna pattern measurement systems, using low-cost off-the-shelf components. We describe the performance-limiting factors of the optical system, and compare measurement results from an MVG Stargate 64 using a standard coaxial cable feed system with those from the optical feed system. The pattern accuracy improvement is significant, demonstrating that this type of system offers a simple and low-cost upgrade for antenna measurement.