Single Channel Microwave Photonics Digital Beamforming Radar Imaging System

We propose and demonstrate the first single channel real-time microwave photonics digital beamforming radar imaging system based on a silica photonics summator. Considering a set of microwave signals received by an antenna array, the number of receiving chains is concentrated into a single channel by achieving an analog time-division multiplexing of radio frequency modulated optical signals using well-calculated optical fiber lengths and a microwave photonics summator. This single channel output guarantees a simplified architecture and minimizes the required number of analog-to-digital converters. A fixed fiber length difference is implemented to introduce a true time delay between each channel in order to time interleave them. The image of the scenes is then retrieved by demultiplexing the received signal and applying digital beamforming techniques. The potential applications of this structure are to implement in a short-range radar imaging system.