Detection of 180/spl deg/ phase discrepancies in multi-port waveguide transmission measurements

It has recently been observed that improper choice of relative adaptor orientations may cause 180/spl deg/ phase discrepancies to appear in the measurement data obtained by automatic network analyzers for the transmission parameters of multi-port rectangular-waveguide components. The present paper describes the use of two different test procedures - based either on the principal sub-determinants of the dissipation matrix or on the maximum singular value of the scattering matrix - to detect the presence of these discrepancies. >