Insertion and conversion loss analysis of a common mode chokes up to 1GHz by four-port chain parameters composed of measured two-port S-parameters

摘要

First, a simple equation using a chain matrix of a four-port network to calculate insertion losses and conversion losses of the four-port network is presented and it is applied to a common mode choke circuit. The differential and common mode insertion losses of a common mode choke are usually defined in a two-port circuit, but a circuit including a common mode choke is usually a four-port circuit and conversion characteristics between a differential mode and a, common mode are important. The presented equation can represent all of the insertion and conversion losses. Second, it is shown that the chain matrix of a common mode choke, which was already developed but not examined well yet in high frequencies, is almost useful up to 1GHz. A chain matrix for a common mode choke used here is obtained from a two-port s-parameter which is measured with TRL calibration.