A Simple Measurement Technique for Characterizing Active Antennas

Abstract- Testing active antennas or polarimetric radar calibrators in the far-field (plane wave excitation) is com-plicated by imperfect isolation between transmitting and re-ceiving channels. We describe a far-field reflectometry setup which overcomes this problem. A large dynamic range is achieved by modulating the active element bias and using a quadrature receiver and lock-in detection scheme. Measured results compare favorably with other existing techniques. I