Title :
A Comparison Between an Absolute Photoacoustic Power Meter and a Brewster Angle Version for Near Millimetre Waves in Free Space
Author :
Moss, D G ; Birch, J.R. ; Martin, D H
Author_Institution :
National Physical Laboratory, Teddington, Middx. TWll 0LW, UK.
Abstract :
The results of a comparison between absolute and non-absolute versions of a photoacoustic power meter for near millimetre waves in free space are presented. The absolute meter has been used to calibrate the non-absolute meter at 60 and 94 GHz. This allows the latter to be used as a secondary standard which can determine power levels of 2 mW with systematic errors of less than 2% and an NEP of 6¿W. Hz¿. The non-absolute meter is a Brewster angle version of the absolute one, and has the advantage of a responsivity which is a slowly varying function of frequency, unlike the absolute meter which has a resonant structure.
Keywords :
Amplitude modulation; Attenuation measurement; Calibration; Frequency measurement; Measurement standards; Optical films; Permittivity measurement; Phase measurement; Resonance; Wavelength measurement;
Conference_Titel :
Microwave Conference, 1991. 21st European
Conference_Location :
Stuttgart, Germany
DOI :
10.1109/EUMA.1991.336443
