The detection of chirped radar signals by means of electron spin echoes

The application of the electron spin echo phenomenon to the detection of chirped microwave pulses is considered. The attainable time resolution is determined by the width of the paramagnetic resonance line, and the length of the received waveform is limited by the phase memory time of the spin packets in the active material. Pulse compressions of 1000:1 appear to be feasible. A typical device of this kind would require to be operated at liquid helium temperatures. It could be adapted so that in itself it provided maser amplification of the compressed pulses.