Reconstruction of the S-Matrix of N-Port Waveguide Reciprocal Devices From 2-Port Vna Measurements

Abstract

Abstract-Two approaches to reconstruct the S-matrix of N -port waveguide reciprocal devices from 2-port S-matrix measurements are proposed and discussed. The main advantage of the proposed approaches is that measurements are done always at the same two ports, without moving the device. The remaining N -2 ports are loaded with different loads, either matched or short. The first approach, based on a manipulation of the 2-port S-matrices, requires N -2 matched and two other loads, while the second approach, based on the evaluation of an equivalent circuit, requires N -2 short and two other loads. The measurement technique is based on standard loads (short, shift and matched) in the waveguide calibration kit of the 2-port VNA.

Identification of Equivalent Circuit Based on Polygon Network for Nonreciprocal Lossy N-Port Device

“…This equivalent circuit is able to also include the presence of evanescent modes [13,14], and it has been applied to some microwave discontinuities, as inductive/capacitive irises, bends and T-junctions [15]. Moreover, similar equivalent circuits have been defined to reconstruct the experimental S-matrix of N -port device with measurements performed only with 2-port Vector Network Analyzer (VNA) [16].…”

Analysis of ``False Non Reciprocity'' in 2-Port Vna Measurements of Reciprocal Devices

“…Another case where high measurement precision is required on S ij is the use of 2-port measurements to evaluate equivalent circuits for lossy 2-port reciprocal devices [1] or the scattering parameters of n-port reciprocal devices. In this case, the measure of the overall S-matrix can be obtained by means of S-matrix reconstruction transforms based on 2-port measurements [2] or with the use of equivalent circuits [3].…”