A 180 GHZ PULSED TRANSMITTER AND HETERODYNE RECEIVER 28 NM CMOS CHIPSET FOR MOLECULAR SENSING

The size, weight, and power requirements of emerging millimeter-wave transmitter and receiver integrated circuit elements make them ideally suited for use in high-resolution \textit{in situ} gas sensors. Previous work at the Jet Propulsion Laboratory has demonstrated a tunable 90-105 GHz transmitter fabricated in 65 nm complementary metal-oxide semiconductor (CMOS) process having phase noise and output power characteristics suitable for making sub-doppler measurements when deployed as the source in a traditional frequency modulated absorption spectrometer.\footnote{D. J. Nemchick \textit{et al.}, ``Sub-Doppler spectroscopy with a CMOS transmitter," \textit{IEEE Trans. THz Sci. Technol.}, vol. 8, no. 1, pp. 121-126, 2018.} When paired with a heterodyne receiver of complementary bandwidth and cavity end mirror outfitted with embedded coplanar waveguides a miniaturized cavity enhanced pulsed Fourier transform spectrometer can be realized where all source and detection electronics are housed on a single 100 cm$^{2}$ printed circuit board. \footnote{D. J. Nemchick \textit{et al.}, A 90-102 GHz CMOS based pulsed Fourier transform spectrometer: New approaches for \textit{in situ} chemical detection and millimeter-wave cavity-based molecular spectroscopy \textit{Rev. Sci. Inst.}, vol. 89, pp. 073109:1-12, 2018} This talk will highlight ongoing work to expand our current capabilities in order to target more strategic molecular transitions, such as the $3_{1,3} \leftarrow 2_{2,0} $ ($J^{\prime\prime}_{K^{\prime\prime}_{a},K^{\prime\prime}_{c}} \leftarrow J^{\prime}_{K^{\prime}_{a},K^{\prime}_{c}} $) H$_{2}$O line at 183.310 GHz, with a new Tx/Rx chipset. Unlike the previous generation these integrated circuit elements, now fabricated with 28 nm CMOS techniques, deploy a 90 GHz phase-lock loop the output of which is either frequency doubled, pulse modulated, then amplified (as in Tx) or frequency doubled for use in pumping a down-conversion mixer (as in Rx). Preliminary results will be presented along with a discussion on how the higher frequency radiation generated from these devices can be coupled into (and out of) an optical cavity to allow for exploitation of sensitive pulsed emission schemes