We developed a stable reference hygrometer suitable for operation at temperatures above ambient that has a robust design, inherent stability, and a well-understood theory of measurement. This hygrometer uses a reentrant, radio-frequency, cavity resonator operating near 370 MHz to convert the known humidity-dependence of the dielectric constant of H2O/air mixture into easily-measured frequency changes. In this paper, we discuss the achievable repeatability of this device. We expect this hygrometer will be especially valuable for validation of humidity standard generators at mixing ratios in moist gases higher than 20000 parts per million by mass.
Proceedings Title: 5th International Symposium on Humidity and Moisture; ISHM 2006 Brazil
Conference Dates: May 2-5, 2006
Conference Location: Rio de Janeiro, -1
Pub Type: Conferences
fuel cell, high humidity, high temperature, humidity standards, hygrometer, radio-frequency, resonat