Characterization of AC/Coaxial Adapter for LISN Calibration Above 30 MHz Using Improved Equivalent Circuit Model

This paper improves the equivalent circuit model of an ac/coaxial adapter for line impedance stabilization network (LISN) calibration above 30 MHz using transmission line theory and evaluates the characteristics of the one-phase adapter for Japan up to 1 GHz using the improved model. Consequently, this adapter severely affects the LISN calibration above 100 MHz, and when the height between the adapter and the reference ground is more than 10 mm, the impact of the ground on its transmission coefficient can be ignored. Additionally, the requirements of a correction method to eliminate the adapter characteristics from the measured LISN characteristics up to 1 GHz are clarified. Finally, the validity of the improved model is indicated by comparison with the measured transmission characteristics of two adapters connected back to back.