1999 - Introducing Height Correction Factors for Accurate Measurements with Biconical Antennas above Groundplane
W. Müllner, M. Buchmayr
13th International Zürich Symposium and Technical Exhibition of Electromagnetic Compatibility,16.-18. Februar 1999, Zürich
The antenna factor of the biconical antenna is a function of antenna height above a ground-plane. Variations in the antenna factor of up to 1.9 dB are observed when the antenna is used in the typical height range of 1 m to 4 m on an open area test site (OATS). The magnitude of this variation depends on the impedance of the antenna balun. From the antenna factor simulations we have derived height correction factors which account for the coupling of biconical antennas above a groundplane. We have demonstrated with antenna calibration measurements what the simulated predictions show. The new method of height correction can be applied to all measurements with biconical antennas, when the balun impedance of the antenna is known. It removes the systematic error caused by the height dependence of the antenna factor. Examples are demonstrated for precision field strength measurements on an OATS, accuracy enhancement for antenna calibration according to the standard site method given in ANSI C63.5 and conversion of OATS antenna factors to free space antenna factors and vice-versa.