Broadband characterisation of CPW transition and transmission line parameters for small reflection up to 100 GHz

The paper presents an alternative approach for de-embedding the coplanar waveguide (CPW) transition from the measured S-parameters of the CPW transmission line. It has the advantage that only S-parameter measurements on two transmission lines, with one twice the length of the other, are required. Once the S-parameters for the CPW transition and transmission line have been distinguished from the measured S-parameters, they are separately characterised using lumped and standard two-port elements, respectively, available in Agilent ADS. 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 100 GHz verifies this approach.