This feature enables to gain quick “smooth” S-parameter plots. The S-parameters at intermediate frequencies are obtained from rational function interpolation Sij(f)=P(f)/Q(f), where P(f) and Q(f) are polynomials with general complex coefficients. The sampling points for the calculation are obtained automatically by comparison of two subsequent interpolations and selection of the one with the largest deviation.
Example of an eight resonator combline filter calculated with 301 frequency steps. The computation time on a quad core Intel® i7 3940XM processor: 316 seconds with “normal” sweep, 34 seconds with “Adaptive” sweep (23 calculated frequency steps).