[7p-N321-1~15] 3.8 Terahertz technologies

4:00 PM - 4:15 PM JST(7:00 AM - 7:15 AM UTC)Presentation by Applicant for JSAP Young Scientists Presentation Award

[7p-N321-10] Homodyne detection with IQ demodulation using circularly polarized terahertz waves

〇Shunto Ommura¹, Adrian Dobroiu¹, Safumi Suzuki¹ (1.Inst. Sci. Tokyo)

Keywords:

Terahertz,Homodyne,IQ demodulation

In terahertz active imaging, the signal scattered back from a target is extremely weak, making high-sensitivity homodyne detection essential. However, any phase offset between the received signal and the local oscillator (LO) prevents accurate amplitude retrieval. While IQ demodulation circuits can overcome this by supplying a quadrature-phase LO, their integration above 300 GHz remains challenging. In this paper, we propose and experimentally demonstrate an IQ demodulation system based on circular polarization using discrete components. By converting the RF beam to circular polarization and mixing it with a constant-phase LO in two orthogonal detection channels, our system simultaneously acquires amplitude and phase information without requiring high-frequency integrated circuits. We present the system design, implementation details, and performance evaluation, confirming its effectiveness for terahertz-band sensing and imaging.