An iterative algorithm to evaluate multimodal S-parameter-measurements

Scattering-(S-)parameters are well established quantities to characterize RF-components both in theory and for measurement purposes. In spite of this, there are very few approaches to measure S-parameters in waveguide environments with more than a single propagating mode. In this paper we present a method for this purpose using a conventional single mode network analyzer, coaxial-waveguide adaptors to be calibrated within the procedure and waveguides of adjustable length. The most important step is the extraction of the devices S-parameters aimed for from the ensemble of single mode measurements. This is done by an iterative algorithm described in this paper.