Observation of semi anechoic room influence on high frequency antenna measurements

Radiation patterns of antennas are among their most important characteristics. A popular method to obtain these consists in measurements inside anechoic chambers. However, in common engineering practice, small laboratories are usually equipped with only one shielded chamber. Such chambers are basically semi anechoic, providing a possibility of their modification to a fully anechoic version by placing appropriate absorbers on their reflective floor. Unfortunately, the systematic placement of absorbers on the floor of the chamber and their re-extraction increases the laboratory operating costs as it is time consuming and, moreover, there is a risk of mechanical wear or damage of the absorbers. Therefore, the authors of this paper decided to explore how great the impact of absorbers placed on the floor of the semi anechoic chamber is in case of measurement of radiation patterns of antennas operating at frequencies of 1 GHz and higher. Description of the experiment and its results are provided within the framework of this paper. © Published under licence by IOP Publishing Ltd.