On-wafer Permittivity Measurement of Dielectric Substrates up to Millimeter Wave Range

In this paper, an in-situ on-wafer measurement method is studied to characterize the dielectric properties of semiconductor substrates in the millimeter wave frequencies. We have designed and fabricated several coplanar waveguide lines (CPW) with different lengths on a GaAs wafer. The multi-line TRL calibration technique is used to correct the impedance mismatch of the measurement system. A comprehensive procedure for calculation of substrate permittivity and dielectric loss tangent is presented. Measurement results up to 110 GHz are given, which agree well with the reference data measured from the resonator method.