SAR with digital beamforming on receive only

Since their invention, the performance of synthetic aperture radar (SAR) systems has improved considerably. Operation close to the theoretical limits of accuracy and resolution are possible using state of the art processing techniques and hardware components. Nevertheless, the principle is still the same: The SAR is a side-looking radar where resolution is achieved in range by bandwidth and in azimuth by Doppler processing. The price for improved performance is paid through systems which are more expensive, heavier and highly complicated. This paper presents a new system idea for a SAR with digital beamforming on receive only. Multiple receive antennas are used together with one or at most two high efficiency transmit antennas. The return signal is separately recorded from each receiving antenna. Application for groundbased, airborne, or spaceborne systems is possible and the system configuration simplifies considerably.