Reduced Order Models for Fast Antenna Characterization

A reduced order model (ROM) for antenna characterization problems is proposed. It exploits the outer dimensions of the antenna under test (AUT) and the geometry of the measurement surface scan and leads to a significant reduction in the required number of field sampling points and, therefore, the time to measure antenna radiation patterns. The inputs of the ROM are the equivalent currents enclosing the AUT, and the outputs are their corresponding radiated fields on the measurement surface. By performing the singular value decomposition (SVD) of the radiating operator, we derive the minimal order model of the system and thereby numerically construct the basis of the fields radiated by the AUT. The evaluation of the so-reduced model is expedited by using a discrete empirical interpolation method (DEIM) that returns the sampling positions of the radiated field. The approach is tailored to the antenna characterization problem and specifically the antenna shape and the measurement surface scan. The proposed methodology is general, and it can be easily adapted to any type of radiating structures and shape of the field measurement scans. Two experimental results of complex radiating structures measured in near field and far field demonstrate the interest and potentialities of the approach.