A Comparative Analysis of Reflectometry Methods for Characterization of Antennas

Traditionally, antenna characterization measurements are performed in the frequency-domain through a Vector Network Analyzer (VNA) in anechoic chamber. Nevertheless, the expensiveness of this set-up prevents it from becoming widespread in laboratories. On such bases, in this paper a time-domain-based approach is comparatively investigated; such a method virtually makes the anechoic chamber unnecessary, thus dramatically reducing the related costs. The proposed approach, based on the evaluation of the scattering parameter (S11) from Time Domain Reflectometry (TDR) data, has been tested for the characterization of a commercial Radio Frequency Identification (RFID) reader antenna. Data acquired in the time-domain are processed in the frequency-domain through a dedicated algorithm, thus allowing the S11 extrapolation. Furthermore, results are compared to VNA measurements performed in an anechoic chamber. In order to assess the investigated method, from a metrological point of view, the root mean square error between the results is reported as a figure of merit. This way, it is demonstrated that calibrated time-domain measurements represent an alternative, inexpensive and accurate method for characterizing antennas.