Bandpass Sampling and Quadrature Demodulation in Synthetic Aperture Radar

There is an increasing performance demand in receiving system of synthetic aperture radar (SAR) in recent days. Different kinds of digital quadrature demodulation (DQD) algorithms are studied and compared in this paper. All DQD algorithms are divided into two classes: with-mixer algorithms and mixer-free algorithms. The condition of mixer-free algorithms is deduced. The performance of different algorithms is evaluated based on simulated echo data of one point target. Simulation shows that filtering delay method is a tradeoff between efficiency and precision. The work in this paper provides a guide to design digital receiver in SAR.