On the validity of bisection-based thru-only de-embedding

The validity of the thru-only de-embedding method that uses mathematically bisected halves of a left-right symmetric THRU pattern is assessed in this paper. The popularly used ¿-equivalent representation of a THRU and the bisection thereof is neither unique nor its validity firmly established. It is shown that an equally simple T-equivalent-based bisection gives better results than the ¿-equivalent-based bisection by comparing the two bisecting methods with a result obtained from an independent method. The thru-only de-embedding method is also compared with the conventional open-short and short-open methods, and the interrelationship among them expected from the assumed equivalent circuit representations of the relevant dummy patterns is confirmed. This is made possible by using the odd-mode responses of symmetric 4-port devices as the 2-ports under study. This way, nonidealities associated with ordinary 2-port dummy patterns is avoided.