Broadband RF Attenuation Standards for Traceability of Antenna and EMC Measurements in Japan

Attenuation standards in the frequency range of 9 kHz to 50 GHz have been established at the National Metrology Institute of Japan (NMIJ/AIST) for ensuring traceability of antenna and EMC measurements in Japan. The standards were realized by two originally developed precision attenuation measurement systems based on the intermediate frequency (IF) substitution method. The first system works in the frequency range of 9 kHz to 1 GHz, built in the highest accuracy dual channel null detection configuration using an inductive voltage divider (IVD) at 1 kHz as IF reference standard. The second system functions to extend the frequency range of 1 GHz to 50 GHz, built in a simple single channel configuration using a step attenuator at 30 MHz as IF reference standard. Traceability of the IVD is obtained directly to the Japan national standard of low-frequency voltage ratio, however, the traceability of the step attenuator standard is obtained through calibration using the first system. Attenuation calibration and measurement capabilities range from 0 to 110 dB with a frequency range of 9 kHz to 50 GHz and an expanded uncertainty range of 0.002 dB to 0.068 dB.