Broadband characterisation of CPW transition and transmission line parameters for small reflection up to 94 GHz

This paper presents an alternate approach of de-embedding the coplanar waveguide (CPW) transition from the measured S-parameters of the CPW transmission line. It has the advantage that only S-parameters measurement on two transmission lines, with one double the length of the other, are required. Once the S-parameters for the CPW transition and transmission line has been distinguished from the measured S-parameters, they are separately characterised using lumped and standard two-port elements available in HP MDS respectively. Good agreement between the simulated and measured S-parameters of a third transmission line (with length different from the two used for characterisation) up to 94 GHz verifies this approach.