Parasitic Probe Effects in Measurements of Conductor-Backed Coplanar Waveguides

Recently, parasitic effects in on-wafer measurements have been investigated thoroughly and can be classified as stemming from probe effects, multimode propagation, crosstalk between adjacent structures and radiation effects. While a lot of investigations have been performed for conventional coplanar waveguides (CPW) measured on ceramic chucks, the parasitic effects occuring in conductor-backed CPWs (CB-CPWs) have not been fully clarified yet. Therefore, this paper demonstrates how parasitic modes and probe effects deteriorate calibrated S-parameters of CB-CPW structures.