DOI: 10.1109/TMTT.2025.3543335   IEEEXplore: https://ieeexplore.ieee.org/document/10910015

A fully integrated wideband THz autodyne FMCW radar with a five-stage voltage-controlled ring oscillator and an on-chip folded slot antenna in a 55-nm BiCMOS process.

360 GHz

To achieve a high bandwidth and a low in-band power variation simultaneously, a five-stage ring oscillator was chosen to generate a 5th harmonic at a lower fundamental frequency (fo) instead of a 3rd harmonic at a higher fo. Higher power gain at fo and higher harmonic power at the 5th harmonic is a result of the low MOS power gain at the higher fo for 3rd harmonic generation. The lower fundamental frequency tuning range required for 5th harmonic generation also results in lower in-band power variation. This radar has the highest bandwidth with the smallest chip area of known VCO-based CMOS radars in the frequency range.

Short-range imaging applications such as dental imaging, for example.

6.2 dBm peak equivalent-isotropically radiated power (EIRP) with 5.8 dB in-band power variation using a hyper-hemispherical silicon lens; 57 GHz bandwidth; 152 mW dc power consumption and 0.16 mm2 chip area.