Evanescent Reactive-Near-Field Measurement for ESPAR Antenna Characterization

A technique to efficiently characterize the azimuth radiation patterns of monopole arrays based on evanescent reactive-near-field measurement in a compact anechoic box is presented. We describe a desktop-size measurement setup for determining the azimuth far-field pattern of an electronically steerable parasitic array radiator (ESPAR) at 2.5 GHz, and present a thorough statistical evaluation of the ESPAR antenna characterization technique. In addition, the sensitivity to probe position and the errors caused by possible fluctuations in the probe position are investigated. Furthermore, comparisons among patterns obtained by the proposed method, simulations and conventional far-field measurements are carried out, and a good agreement among them is obtained. We also provide a statistical evaluation of the proposed desktop-size measurement setup using forty ESPAR antennas and conclude that the proposed setup can be an inexpensive candidate to replace the conventional measuring system