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Subcarrier Frequency-Modulated Continuous-Wave Radar in the Terahertz Range Based on a Resonant-Tunneling-Diode
Adrian Dobroiu1, Yusuke Shirakawa1, Safumi Suzuki1
1Tokyo Institute of Technology, Meguro, Tokyo 152-8552, Japan.
Sensors (Basel, Switzerland)
|December 3, 2020
Summary
We present a novel terahertz-wave distance measurement using a resonant-tunneling-diode (RTD) oscillator and frequency-modulated continuous-wave (FMCW) radar. This method modulates a subcarrier, enabling precise measurements even with less stable oscillators.
Area of Science:
- Terahertz (THz) technology
- Radar systems engineering
- Solid-state device physics
Background:
- Terahertz (THz) waves offer unique properties for sensing and imaging.
- Traditional frequency-modulated continuous-wave (FMCW) radar requires precise control of the carrier frequency.
- Resonant-tunneling-diode (RTD) oscillators are compact THz sources but can have limited frequency stability.
Purpose of the Study:
- To develop a new distance measurement principle for the terahertz-wave range.
- To adapt the FMCW radar technique for sources with amplitude modulation capabilities but limited frequency control, such as RTD oscillators.
- To demonstrate the feasibility of this novel approach through experimental validation.
Main Methods:
- Utilizing a 511 GHz resonant-tunneling-diode (RTD) oscillator as the terahertz source.
- Implementing a modified FMCW radar technique by applying frequency modulation to an amplitude-modulated subcarrier, rather than the main carrier.
- Conducting proof-of-concept experiments to validate the distance measurement principle.
Main Results:
- Successfully demonstrated a new principle for terahertz-wave distance measurement.
- Validated the effectiveness of subcarrier frequency modulation for FMCW radar using an RTD oscillator.
- Achieved proof-of-concept experimental results confirming the viability of the proposed method.
Conclusions:
- The proposed subcarrier modulation technique offers an advantageous approach for terahertz FMCW radar, particularly with amplitude-controllable sources like RTD oscillators.
- This method enhances the applicability of FMCW radar in scenarios where precise carrier frequency control is challenging.
- The findings pave the way for practical terahertz-based distance measurement systems utilizing readily available RTD oscillators.
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