An Efficient Scheduling for Fast Calibration of Digital Beamforming Active Phased Array Radar

Abstract

A 40-channel digital beamforming transceiver with wave-guide slot array antenna used in S-Band phased array radar is presented in this paper. It can steer 16 beams at elevation angle simultaneously. Each slot array antenna used a TRM (Transmit and Receive Module), RF to IF downconverter, high-speed ADC (Analog to Digital Converter) for calibration, and DBF (Digital Beam Forming). The TRM, calibration architecture, and timing are described in detail. An accurate and fast calibration scheme, less than one second, with the exact and efficient scheduling for calibration is proposed. The method measures the phase and amplitude offset between the IF signal generated by SPU (Signal Process Unit) that injects TRM with an IF signal comeback to SPU from TRM at the same frequency. Accordingly, the SPU adjusts its phase and amplitude in order to align to the reference phase in the allocated timing. The result in accuracy and fast calibration is obtained in DBF phased array radar.