A set of waveguide primary thermal noise standards and related calibrationsystems for the frequency range 8.2-40 GHz

The national metrology laboratory, BNM-LCIE, France, has developed a set of four new waveguide primary thermal noise standards for the frequency hand from 8.2 GHz to 40 GHz, Each noise standard is made with silicon carbide mi crowave absorber and inserted into a section of waveguide made in platinum 10% rhodium; the whole is put inside an electrical oven. The output noise t emperature range of the standards obtained from temperature and attenuation measurements is within 948-1012 K +/- 1.2-1.8 K, in one standard-type unce rtainty. The calibration of gas discharge noise sources and/or solid-state noise sources is achieved by comparison to standards using a switching radi ometer. The excess noise ratio given is within 15.35-15.65 dB for gas disch arge sources and within 14-16 dB for solid-state sources, with typical unce rtainty of 0.02 dB.