SBIR-STTR Award

This proposal is responsive to NASA SBIR Subtopic S1.03: Technologies for Passive Microwave Remote Sensing; specifically the last bullet item related to GaAs Schottky diode harmonic mixers for the 2-5 THz frequency band. Through this proposed SBIR project, VDI seeks to extend the performance of high-quality harmonic mixers to frequencies up to 5 THz; with the primary goal of meeting the requirements of planned and future NASA missions. This effort will focus primarily on second and fourth harmonic mixers which will use advanced circuit designs and fabrication technologies to maintain low conversion loss while also reducing the complexity of the local oscillator source. Potential NASA Applications The primary applications will be studies of planetary atmospheres, heliophysics and radio astronomy. Of particular importance is the study of water chemistry on planets and moons. Many of the molecules related to water chemistry have transitions in the frequency band that will be accessed by the new mixers. For radio astronomy, the harmonic mixers will be used to phase lock QCLs, which are becoming the technology of choice to supply the LO power for ultra-sensitive cryogenic receivers. Potential Non-NASA Applications This research will open a new spectral band for more practical scientific exploitation. Scientific fields that require high quality THz mixers include nuclear fusion plasma diagnostics, molecular spectroscopy, environmental sensing, materials characterization and basic physics. More commercial applications will include the extension of the frequency range of test and measurement, such as vector network and signal analysis.

The goal of this proposal is to extend Schottky receiver technology through the frequency range from 2 to 5 THz, with emphasis on the needs of future NASA missions. Initial examples include the SSOLVE receiver at 2.5 THz and a heliophysics mission concept at 4.7 THz. In general, the Schottky receiver technology will be useful for all missions in this frequency range that cannot make use of cryogenic receivers. Important examples will include planetary and lunar probes, atmospheric studies and heliophysics. Also, the source technology that will be demonstrated to pump the Schottky mixers can also be used as local oscillator sources for large arrays of cryogenically cooled hot electron bolometer receiver arrays, such as those planned for SOFIA and other platforms. Potential NASA Applications (Limit 1500 characters, approximately 150 words) The Schottky receiver technology will be useful for all missions in the 2-5 THz frequency range that cannot make use of cryogenic receivers. Important examples will include planetary and lunar probes, atmospheric studies and heliophysics. Initial examples include the SSOLVE receiver at 2.5 THz and a heliophysics mission concept at 4.7 THz. Also, improved source technology will be used to pump large arrays of cryogenically cooled hot electron bolometer receiver arrays, such as those planned for SOFIA and other platforms. Potential Non-NASA Applications (Limit 1500 characters, approximately 150 words) Molecular spectroscopy, plasma and accelerator diagnostics and materials science. Commercial test and measurement equipment will be extended to higher frequency. The receivers and sources will replace time domain terahertz systems for spectroscopy. The more powerful solid-state LO sources will also supplant vacuum tube technologies.