Characterizing the Electric Field Ripple in Reflector Antennas Using Subsampled Exponential Analysis

Reflector antennas often exhibit frequency ripples in key performance metrics, including aperture efficiency and antenna noise temperature. These ripples stem from corresponding fluctuations in the electric field pattern, due to interference between fields radiated, reflected, or diffracted by the feed and reflectors, and it is important that they are characterized. In this article, we introduce an innovative approach for reconstructing the electric fields of reflector antennas using simulated data across a range of frequencies. By leveraging the power of sub-Nyquist sampling, the number of required samples can be reduced, leading to increased computational efficiency. This presents an advantage to traditional methods such as the Fourier transform that requires Nyquist sampling. We demonstrate how these reconstructions can be used to characterize the frequency contents of resulting reflector properties, such as aperture efficiency and antenna noise temperature.