A high-sensitivity laboratory system for measuring the microwave properties of gases under simulated conditions for planetary atmospheres

• Published in: Radio science 2007-12, Vol.42 (6), p.np-n/a
• Main Authors: Hanley, Thomas R., Steffes, Paul G.
• Format: Article
• Language: English
• Subjects: gas; measurement; microwave
• ISSN: 0048-6604; 1944-799X
• DOI: 10.1029/2007RS003693

A system for measuring the microwave properties of gases under simulated conditions for planetary atmospheres has been under continuous development at Georgia Tech for over 2 decades (see, e.g., DeBoer and Steffes, 1996). The measurements from this system form the basis for accurately modeling the microwave properties of gases under various planetary conditions, which are essential in determining the presence and concentration of such gases through various microwave remote sensing techniques. This system consists of two independent configurations, one capable of measuring gas mixtures up to pressures of 3 bars at frequencies from 22 to 40 GHz, and another capable of pressures up to 12 bars over the frequency range from 1.5 to 24.1 GHz. The former configuration exhibits maximum 2‐σ sensitivities in absorptivity of 0.25 dB/km and in refractivity of 2.0, while the latter configuration exhibits maximum 2‐σ sensitivities in absorptivity ranging from 0.01 dB/km at 1.5 GHz (20 cm) to 1.0 dB/km at 24.1 GHz (1.25 cm) and in refractivity from 0.05 at 1.5 GHz to 3.13 at 24.1 GHz.