Gain Averages as Criteria for Antenna EMC-Performance

• Published in: 1972 IEEE International Electromagnetic Compatibility Symposium Record pp. 1 - 4
• Main Author: Halberstein, Joseph H.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.07.1972
• Subjects: Antenna measurements; Electromagnetic compatibility; Gain; Interference; Radar antennas
• ISBN: 9781509031580; 1509031588
• DOI: 10.1109/ISEMC.1972.7567696

Much of the antenna coupling prediction and specification work done for EMC relies on the mean and/or median of the gain values taken in dB of the antenna patterns concerned. Often the measured Pattern Distribution Function (P.D.F.) is approximated by a cumulative normal probability function of the dB-gain-values and its median or mean and standard deviation is taken as indication of the EMC performance of the antenna. The question is raised whether a criterion can be found which is more directly related to the operational EMC performance of antennas. It turns out that such a criterion exists and is closely tied to the straight average of gain rather than the average of dB-values. For antenna patterns with cumulative normal P.D.F.'s a closed expression for the difference between dB and straight average is found. It is shown that the difference between the average or median dBgain and the straight average of the gain is typically 10-20 dB but may be even higher. The difference varies strongly with the standard deviation of the pattern distribution function.