Investigations on self injection locked THz RTD Radars

In this work, novel self injection locked oscillator (SILO) radars realized in indium phosphide resonant tunneling diode technology are investigated regarding their performance in ranging and target detection. Exemplary experimental data demonstrates high potential for future radar applications. Frequency-comb-based operating modes are further demonstrated experimentally and serve as proof-of-concept. The longest measured distance is 20 m at a fundamental emission frequency of 663 GHz. Frequency modulation of the free running SILO through self injection locking provides total target distances, target velocity, and direction of motion without externally controlling the oscillator’s operating point or emitted frequency. Operation of the SILO in various comb modes, with over 30 GHz of comb bandwidth and 1.5 GHz of sub-comb bandwidth was demonstrated at 2 m distance to a metallic target. A terahertz (THz) SILO radar using an injection-locked self-oscillating RTD mixer (SOM) for down-conversion of the SILO’s frequency output was realized by externally injection locking of the SOM to a THz photonic source.