2001 - Site Attenuation of Limited-Size Ground planes for vertical Polarisation
14th International Zürich Symposium and Technical Exhibition on Electromagnetic Compatibility, February 20-22, 2001, Zürich W. Müllner*, A. Kriz**
We have investigated the site attenuation per-formance of open area test sites for vertical polarization in the frequency range from 30 MHz up to 200 MHz. The results have been obtained by numerical simulation using FDTD. Practical measurements and NEC, an other numerical simulation method, have been used for verification. We have found that the site attenuation in vertical polarization depends in contrary to horizontal polarization strongly on the size of the ground plane. Edge effects influence the accuracy of all field strength and site attenuation measurements. The site attenuation shows a deviation of up to +/- 2 dB on a perfect, but limited-size ground plane. Measurements with the receive antenna not positioned in the height scan maximum should be avoided as errors up to 15 dB may arise. When calibrating an antenna according to the reference antenna method in vertical polarization an identical antenna type has to be used as reference antenna to avoid edge effect errors.