The Shannon channel capacity of a radar system

A radar system can be used in conjunction with a coherent transponder as a communications system. A coherent transponder ("RF tag") received a stream of radar pulses, modifies these and transmits them back to the radar. This enables the RF tag to embed information in the radar data stream. We derive capacity formulas for this radar channel and then calculate these capacities for a specific SAR radar system and the RF tag configuration. We characterize the dependence of capacity on pulse repetition frequency, standoff range, and resolution.