Sparse Inverse Chirp-Z Transform of S-Parameter Measurements for Time Domain Analysis of Transmission Line

Time-domain analysis of S-Parameters can be performed by converting data collected in the frequency to time domain. Although the use of the Chirp Z Transform approach, a more general Fourier transform tool, flexibilizes data acquisition, the conversion (or inversion) becomes difficult. Most existing methods approximate the Inverse Chirp Z transform by a minimum norm solution, which does not have strong physical support. In this paper, we propose a Sparse Inverse Chirp Z transforms specially crafted for sparse time-domain signals representing spikes generated at impedance discontinuities. The method is verified by comparing time-domain results of S- Parameters extracted of a cascaded transmission line set to the ones given by ADS Keysight® software, showing good agreement in reflection and transmission behavior of the line.