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Lee, K. A.

Publications and source records attributed to Lee, K. A..

The Fourier-Kelvin Stellar Interferometer a Low Complexity, Low Cost Space Mission for High-Resolution Astronomy and Direct Exoplanet Detection

The Fourier-Kelvin Stellar Interferometer (FKSI) is a mission concept for a spacecraft-borne nulling interferometer for high-resolution astronomy and the direct detection of exoplanets and assay of their environments and atmospheres. FKSI is a high angular resolution system operating in the near to midinfrared spectral region and is a scientific and technological pathfinder to the Darwin and Terrestrial Planet Finder (TPF) missions. The instrument is configured with an optical system consisting, depending on configuration, of two 0.5 - 1.0 m telescopes on a 12.5 - 20 m boom feeding a symmetric, dual Mach- Zehnder beam combiner. We report on progress on our nulling testbed including the design of an optical pathlength null-tracking control system and development of a testing regime for hollow-core fiber waveguides proposed for use in wavefront cleanup. We also report results of integrated simulation studies of the planet detection performance of FKSI and results from an in-depth control system and residual optical pathlength jitter analysis.

Barry, R. K.↗

A 32-GHz solid-state power amplifier for deep space communications

A 1.5-W solid-state power amplifier (SSPA) has been demonstrated as part of an effort to develop and evaluate state-of-the-art transmitter and receiver components at 32 and 35 GHz for future deep space missions. Output power and efficiency measurements for a monolithic millimeter-wave integrated circuit (MMIC)-based SSPA are reported. Technical design details for the various modules and a thermal analysis are discussed, as well as future plans.

Wamhof, P. D.↗

A 32-GHz phased array transmit feed for spacecraft telecommunications

A 21-element phased array transmit feed was demonstrated as part of an effort to develop and evaluate state-of-the-art transmitter and receiver components at 32 and 34 GHz for future deep-space missions. Antenna pattern measurements demonstrating electronic beam steering of the two-dimensional array are reported and compared with predictions based on measured performance of MMIC-based phase shifter and amplifier modules and Vivaldi slotline radiating elements.

Lee, K. A.↗

Planar Antennas On Thick Dielectric Substrates

Features include ease of fabrication and wide range of operating frequencies. Planar antennas on thick dielectric substrates built for use at millimeter wavelengths from 40 to 400 GHZ. Antennas of this type quasi-optical structures, for which expensive, precisely machined waveguides not required. Made easily by standard photolithography and integrated with planar mixers or detectors to form arrays.

Lee, K. A.↗