Noise Sources for 0.1 - 1.0 THz

This proposal is responsive to NASA SBIR Subtopic S11.03: Technologies for Passive Microwave Remote Sensing (SBIR), Scope Title: Components or Methods to Improve Sensitivity, Calibration, or Resolution of Microwave/Millimeter-Wave Radiometers; specifically, the bullet item “Noise sources from G-band up to 1 THz with >6dB ENR (excess noise ratio).” Noise sources serve as calibration references for receiver systems used in radio astronomy and atmospheric remote sensing. The goal is to calibrate out the instabilities of the receiver system, for example, gain fluctuations in low noise amplifiers (LNAs). To achieve this the noise source must have sufficient power, expressed as the excess noise ratio or ENR. Generally, an ENR of about 10dB is sufficient, although greater ENR can enable improved performance for noise injection radiometers (e.g. by requiring reduced coupler factor) and in test and measurement (e.g. overcoming coupling loss to the device under test). The other primary requirement is that the noise source itself must have sufficient stability. VDI has recently demonstrated improved performance above 110 GHz using a new diode Schottky diode design. Specifically, ENR above 10dB up to 220 GHz and useful ENR to 330 GHz have been demonstrated. Through the proposed Phase I research VDI will demonstrate the feasibility of this technology to achieve NASA’s stated goal, and to investigate how high in frequency this technology can be extended through Phase II research and development.