Inductively Coupled In-Circuit Measurement of Multiport Admittance Parameters

This letter proposes an inductively coupled in-circuit measurement method for the characterization of the admittance matrix of multiport systems at radio frequencies. The measurement setup involves inductive probes connected to a vector network analyzer, each one defining a longitudinal port along the clamped wire. The rationale of the method is firstly presented in general terms for an arbitrary number N of probes, allowing measurement of an N×N admittance matrix. Then, the involved equations are fully developed in closed form for the case N=2, which assumes special importance since, by virtue of the admittance-matrix definition, any number of ports can be managed by multiple two-port measurements. The proposed method is experimentally verified using a set of passive networks.