Imaging Applications with a Single Resonant Tunneling Diode Transceiver in 300-GHz Band

A resonant tunneling diode (RTD) is a promising device for future terahertz (THz) applications owing to its capacity to operate as both a transmitter and a receiver of THz waves. It is noteworthy that the RTD can simultaneously detect incoming terahertz signals while operating as an oscillator. In this study, we investigated the possibility of employing a single RTD transceiver module as both a source and a detector in THz sensing applications. Such a configuration can greatly simplify THz imaging systems while maintaining excellent phase stability owing to the injection locking phenomenon. The developed imaging system identifies small deformation with a dimension of approximately 0.1 mm from a distance of ~70 cm. Finally, two-dimensional imaging of 0.3-mm-thick tape was successfully demonstrated.