Loop calibrator for DBF receiver array at Ka-band

On-line calibration is an important task in communication systems. To achieve high-performance in a simple way, the loop calibrator concept is applied to a receiver array at Ka-band. Non-directive stripline couplers are used to feed calibration signals into each receiver channel through capacitive coupling. A three-antenna array is built and characterized to validate the calibration concept. Errors caused by imperfections of the calibration system are analyzed in time domain signal pattern.