The heterodyne beat method has been applied to the measurement of the dielectric constant of gaseous NH3, N2, and CO2, using a frequency of 56,000,000 cycles per second. Special precautions were found necessary to prevent frequency drift and synchronization of the oscillating circuits.
Proceedings of the Iowa Academy of Science
©1939 Iowa Academy of Science, Inc.
Ryan, Alden H.
"The Dielectric Constant of Gases at Ultrahigh Frequencies,"
Proceedings of the Iowa Academy of Science, 46(1), 268-268.
Available at: https://scholarworks.uni.edu/pias/vol46/iss1/82