PT Journal
AU Kasparek, W
   Fernandez, A
   Hollmann, F
   Wacker, R
TI Measurements of ohmic losses of metallic reflectors at 140 GHz using a 3-mirror resonator technique
SO Int. J. Infrared and Millimeter Waves
PY 2001
BP 1695
EP 1707
VL 22
IS 11
DE mirror; reflection index; emissivity; Fabry-Perot interferometer; subterahertz; subTHz
AB The reflectivity of metallic mirrors in the millimeter wave region does not only depend on the material, but also on the structure and roughness of the surface. We have performed measurements of the reflectivity of various plane and grooved metallic and graphite samples at 140 GHz. The technique is based on the comparison of the quality factor of a 2-mirror reference resonator with the quality factor of a 3-mirror resonator which has identical dimensions and includes the mirror to be tested. After a brief presentation of the theory, the set-up is described and the reflection loss for various aluminium and copper mirrors as well as vacuum compatible materials for applications in thermonuclear fusion experiments are presented and discussed.
ER