Discrete Fourier Transform Radar in the Terahertz-Wave Range Based on a Resonant-Tunneling-Diode Oscillator

Abstract

We used a resonant-tunneling-diode (RTD) oscillator as the source of a terahertz-wave radar based on the principle of the swept-source optical coherence tomography (SS-OCT). Unlike similar reports in the terahertz range, we apply the stepwise frequency modulation to a subcarrier obtained by amplitude modulation instead of tuning the terahertz carrier frequency. Additionally, we replace the usual optical interference with electrical mixing and, by using a quadrature mixer, we can discriminate between negative and positive optical path differences, which doubles the measurement range without increasing the measurement time. To measure the distance to multiple targets simultaneously, the terahertz wave is modulated in amplitude at a series of frequencies; the signal returning from the target is detected and homodyne mixed with the original modulation signal. A series of voltages is obtained; by Fourier transformation the distance to each target is retrieved. Experimental results on one and two targets are shown.

Resonant Tunneling Diodes High-Speed Terahertz Wireless Communications - A Review

“…Compared with InP-based RTDs, antimonides-based RTDs promise superior speed and power performances [182], and so may underpin future THz TRx systems. Beyond wireless communications, it is important to mention that THz RTD oscillators are also being developed for other applications, including compact high-resolution imaging [183]- [185], spectroscopy [186], and radar [187]- [189] systems. It would therefore seem that the RTD is a very promising candidate technology for many practical THz applications.…”

Investigation of heat-dissipation structures in resonant tunneling diodes and their characteristics on terahertz oscillators

“…[5][6][7][8][9][10][11] Resonant tunneling diodes (RTDs) stand out as promising candidates for THz sources, having achieved fundamental oscillations up to 2 THz, and the demonstrations of THz applications employing RTD oscillators have been reported. [12][13][14][15][16][17][18][19] A noteworthy achievement includes obtaining high output power (0.7 mW at approximately) at approximately 1 THz with a large-scale oscillator array. 20) However, this array suffered from a multipeak oscillation spectrum due to a lack of synchronization among its elements stemming from the absence of a coupling structure.…”

Bistability of AlGaAs/GaAs Resonant-Tunneling Diodes Heterostructural Channel

“…This is relevant for biomedical applications (including the concept of “smart city”), as well as for improving the electromagnetic compatibility of devices within the network’s range by reducing the reader’s radiation power. In addition, the attractiveness of RTDs as nonlinear elements of radio-electronic sensors is due to the possibility of increasing the operating frequencies of these devices up to the terahertz range [ 4 , 5 , 6 , 7 ].…”