Fast Antenna Characterization With Numerical Expansion Functions Built With Partial Knowledge of the Antenna and Accelerated Asymptotic Methods

We describe a method to use numerical simulations concurrently with measurements (near-field data) to characterize the radiation properties of an antenna (far-field) with a strongly reduced number of samples. Both the simulations and experimental data are dealt with as sources of information toward obtaining the desired characterization. Simulations compensate for data scarceness, allowing to obtain an accurate characterization with fewer data than with measurements only, and the few measured data allow the comprehensive numerical proxy to get tuned to the true antenna under test (AUT). The method uses partial knowledge of the antenna and leverages accelerated asymptotic numerical methods to perform the numerical simulations needed by the algorithm. We report experimental tests of performance, both in terms of accuracy and speed-up with respect to the classical methods, with reflector antennas up to 27 wavelength. It is important to note that good results are obtained both when samples are taken on irregular optimized grids and on regular grids usually resulting from the conventional measurement rigs.