Assessment of Antenna Polarization Effect on Radiated Emissions Measurement

Antennas with reconfigurable polarization capability are useful to diminish losses affected by multi path fading, thereby enhancing the efficiency of transceived signals. This is undertaken by minimizing disparities in antenna polarization and signal interference with others. This paper assesses the effect of antenna polarization on radiated emissions measurement of equipment under test (EUT). The measurements are conducted at an EMI test system using microstrip antenna in the frequency range of 30 MHz to 1000MHz. As comparison, the measurement using an Ultralog antenna is also performed in the same frequency range. The used microstrip antenna is designed to work with different polarization modes, specifically linear polarization (LP), left hand circular polarization (LHCP), right hand circular polarization (RHCP). From the measurement results, the electric field strength levels in vertical polarization are higher than that in horizontal polarization for all polarization modes of microstrip antennas. The varying level of electric field strength in vertical polarization is in the ranges of 85.59 dBμV/m to 86.91 dBμV/m, while in horizontal polarization mode is 70.70 dBμV/m to 80.42 dBμV/m.