Fig. 1: Time-variant PT-symmetric frequency-scanning system.
From: Time-variant parity-time symmetry in frequency-scanning systems
a Illustration of a time-invariant PT-symmetric single-frequency system (upper) and the produced single-frequency signal (lower). b Illustration of a time-variant PT-symmetric frequency-scanning system (upper) and the produced frequency-scanning signal (lower). c Instantaneous gain-time diagram (left) and net gain at a certain time window (right) for a conventional frequency-scanning system. a.u.: arbitrary units. d Instantaneous gain-time diagram (left) and net gain at a certain time window (right) for the PT-symmetric frequency-scanning system. e Example of the time-variant PT-symmetric frequency-scanning system in practical applications. It can be used as a key signal source to provide the required FMCW waveform for radar and lidar systems.
