Evaluate the dielectric thickness variation of thin-film microstrip line by time domain reflectometry

Abstract

The impedance distribution measured by time domain reflectometry is utilized in estimating the thickness variation of the dielectric layer in a thin-film microstrip line. The relationship between dielectric thickness and impedance variation is derived based on an approximate formula. Measurements are carried out and a maximum linear fitting algorithm is proposed to correct the series resistance effect in the time domain reflectometer (TDR) data.<>