This paper presents an overview of a sub-orbital flight demonstration with a 183 GHz and 540–600 GHz limb-sounding instrument aboard a stratospheric ballooncraft. The 183 GHz band provides soundings of stratospheric H 2 O and is implemented with a hybrid CMOS-InP receiver architecture which provides excellent sensitivity while remaining compact (162 g) and offering an extremely low DC power consumption (0.62 W). The 540–600 GHz channel sounds stratospheric O 3 and uses a combination of a CMOS local oscillator, GaAs Schottky mixer and micro-electro-mechanical-system (MEMS) RF switch for calibration, again offering competitive form factor (1.4 Kg) and low DC power consumption (6.6 W) compared to prior instruments. The instrument was flown on the NASA Reck-Tang Limb-sounding Experiment (ReckTangLE) ballooncraft and performed atmospheric soundings across New Mexico and Northwestern Texas on Oct. 17 2019.@en

The performance of a CMOS transmitter designed for planetary science in-situ molecular sensing applications having an operational bandwidth of 180-190 GHz and peak output power of 0.6 mW (-2.22 dBm) is evaluated with a series of spectroscopic-based experimental trials. Continuous wave frequency modulated absorption schemes are exploited to probe the Doppler and sub-Doppler lineshape profiles of the water rotational transition at 183.310 GHz. These results demonstrate the tuning finesse and phase-noise characteristics of the integrated circuit embedded phase lock loop used to generate coherent mm-wave radiation are sufficient for high-precision molecular spectroscopy applications. A description of the pulse modulator designed into the CMOS circuitry allowing for implementation of sensitive emission-based Fourier transform detection schemes is provided with performance characterized for spectroscopically relevant pulse durations (40-500 ns). Results are accompanied by a spectral analysis of the transmitter pulse signal leakage where the total isolation is measured to be 22 dB. The first emission-based molecular detections obtained with this source are presented demonstrating viability for this transmitter to be incorporated into future planned resonant cavity enhanced in-situ molecular sensing systems.@en

The performance of a CMOS transmitter designed for planetary science in-situ molecular sensing applications having an operational bandwidth of 180-190 GHz and peak output power of 0.6 mW (-2.22 dBm) is evaluated with a series of spectroscopic-based experimental trials. Continuous wave frequency modulated absorption schemes are exploited to probe the Doppler and sub-Doppler lineshape profiles of the water rotational transition at 183.310 GHz. These results demonstrate the tuning finesse and phase-noise characteristics of the integrated circuit embedded phase lock loop used to generate coherent mm-wave radiation are sufficient for high-precision molecular spectroscopy applications. A description of the pulse modulator designed into the CMOS circuitry allowing for implementation of sensitive emission-based Fourier transform detection schemes is provided with performance characterized for spectroscopically relevant pulse durations (40-500 ns). Results are accompanied by a spectral analysis of the transmitter pulse signal leakage where the total isolation is measured to be 22 dB. The first emission-based molecular detections obtained with this source are presented demonstrating viability for this transmitter to be incorporated into future planned resonant cavity enhanced in-situ molecular sensing systems.@en

We report on the architecture and performance of a highly sensitive 95 GHz Doppler radar instrument with 0.6Watt transmit power designed for low power consumption and small size. The radar's sensitivity is validated using a calibration target, and its remote sensing capabilities are demonstrated through the detection of clouds, rain, insects, and distant vehicles. The radar uses a frequency-modulated continuous-wave (FMCW) waveform, a single antenna with ultra-high-isolation quasioptical transmit/receive duplexing, an InP low-noise amplifier for receiving, and a GaN power amplifier for transmitting. A DC power consumption of 22 W for the RF and digital subsystems is achieved, in part, by a combination of a power-efficient waveform generation/detection and signal processing board and a CMOS-based system-on-chip W-band oscillator. Excluding power supplies and a computer interface, the radar system mass is under 6 kg, making it attractive for future deployment from platforms with constrained accommodation resources.@en

This paper presents a Ku -band (14-16 GHz) CMOS frequency-modulated continuous-wave (FMCW) radar transceiver developed to measure dry-snow depth for water management purposes and to aid in retrieval of snow water equivalent. An on-chip direct digital frequency synthesizer and digital-to-analog converter digitally generates a chirping waveform which then drives a ring oscillator-based Ku -Band phase-locked loop to provide the final Ku -band FMCW signal. Employing a ring oscillator as opposed to a tuned inductor-based oscillator (LC-VCO) allows the radar to achieve wide chirp bandwidth resulting in a higher axial resolution (7.5 cm), which is needed to accurately quantify the snowpack profile. The demonstrated radar chip is fabricated in a 65-nm CMOS process. The chip consumes 252.4 mW of power under 1.1-V supply, making its payload requirements suitable for observations from a small unmanned aerial vehicle.@en

A 95 GHz Doppler radar prototype has been developed with a design guided by requirements for potential space flight missions to comets or icy moons of the outer planets in order to probe ice- and dust-filled jets and plumes. The radar operates in a frequency-modulated continuous-wave (FMCW) mode with a bandwidth, pulse repetition interval, and coherent integration time chosen to achieve better than 10 m range resolution, 0.1 m/s velocity resolution, 5.1 km maximum unambiguous range, and 46 m/s maximum unambiguous velocity span. With an ultra-high transmit/receive isolation exceeding 85 dB, the radar operates with thermal-noise-limited sensitivity even with 1 Watt of continuous transmit power and a 540 K noise-temperature receiver sharing a single, 15 cm diameter monostatic aperture. Experimental testing has verified the radar's range-Doppler remote sensing capabilities using a developing rain shower as a dynamic and distributed target.@en

The exploration of icy body composition in the solar system has often involved spectroscopic measurements of volatiles detected with remote sensing, such measurements portray materials naturally expelled from the surface that enter the exosphere and potentially escape into space. Variations in the ratio of deuterium and hydrogen in these measurements have led to inconclusive hypotheses regarding potential cometary origins of Earth’s ocean water and/or organics. Observational biases regarding unknown previous processing of the observable ejected materials necessitates studies of more dormant, less-processed bodies. Landed missions on comets have brought focus onto the development of small, sensitive instrumentation capable of similar composition measurements of the nascent surface and near-surface materials. We present an evolution of our compact Fourier-transform millimeter-wave cavity spectrometer that is tuned for sensitivity at 80.6 and 183 GHz where HDO and H2O exhibit resonance features. We discuss both a low-SWaP (size-weight and power) architecture that uses custom microchip transceiver elements as well as a modular configuration using traditional GaAs-based millimeter-wave hardware. New design features for these systems including quartz-based coupling elements, system thermal management, and a separable clocking board are discussed in addition to sensitivity studies and applications in potential mission scenarios.@en

Using newly developed silicon micromachining technology that enables low-mass and highly integrated receivers, we are developing state-of-the-art terahertz spectrometer instruments for space-based planetary and astrophysics orbiter missions. Our flexible receiver with integrated antenna architecture provides a powerful instrument capability in a light-weight, low-power consuming compact package which offer unprecedented sensitivity performance, spectral coverage, and scalability to meet the scientific requirements of multiple missions.@en