Abstract-Toward a solid-state, compact, terahertz-wave radar

Conference Proceedings

Adrian Dobroiu, Ryotaka Wakasugi, Masafumi Suzuki,  Masahiro Asada, 

https://aip.scitation.org/doi/10.1063/1.5089437

We report the principle and first experimental results on a terahertz-wave radar based on a resonant-tunneling diode (RTD) working as a 522 GHz radiation source and a Schottky barrier diode (SBD) as a detector. By modulating the output power of the RTD at two frequencies and measuring the corresponding phase delays after the terahertz wave propagates from the source to the detector, we were able to measure the absolute propagation distance between them (including all the cables carrying the signals) with an error of about 10 mm. We then combined this absolute distance with the phase delay measured at one frequency to further reduce the error of the distance measurement to below 0.4 mm.

Abstract-Absolute and Precise Terahertz-Wave Radar Based on an Amplitude-Modulated Resonant-Tunneling-Diode Oscillator

Adrian Dobroiu, Ryotaka Wakasugi, Yusuke Shirakawa, Safumi Suzuki,  Masahiro Asada

https://www.mdpi.com/2304-6732/5/4/52

We present the principle of a terahertz-wave radar and its proof-of-concept experimental verification. The radar is based on a 522 GHz resonant-tunneling-diode oscillator, whose terahertz output power can be easily modulated by superimposing the modulation signal on its bias voltage. By using one modulation frequency and measuring the time delay of the returning signal, a relative measurement of the propagation distance is possible; adding a second modulation frequency removes the ambiguity stemming from the periodicity of the modulation sine wave and allows an absolute distance measurement. We verified this measurement method experimentally and obtained a submillimeter precision, as predicted by theory.