Antenna calibration in anechoic chamber

Radiated Emission testing of commercial products are usually performed on open area test site. This measurement requires receiver & sensors for pick up the emission. Test receiver & sensor shall be calibrated periodically for accurate measurement. Antenna usually calibrated as per ANSI C63.5-1988 specification on OATS. Due to use of various communication equipment, measurement on OATS needs special attention. Minor negligence can produce wrong data. To over come this problem, Radiated emission has to be performed in Anechoic Chamber for better repeatability & re-reducibility. Performing the calibration on OATS & measurement in anechoic chamber are require both facilities. In-view of above, a study has been conducted to find out the alternative of antenna calibration in anechoic chamber. This articles describes the details of antenna calibration performed in anechoic chamber as out lined in the document ANSI C63.5-1988 (Standard site method). Measurement data taken in OATS & anechoic Chamber have been compared & analyzed. Possible causes of variability in observations are also discussed.