Development of gallium-arsenide-based GCPW calibration kits for on-wafer measurements in the W-band

We present details of on-wafer-level 16-term error model calibration kits used for the characterization of W-band circuits based on a grounded coplanar waveguide (GCPW). These circuits were fabricated on a thin gallium arsenide (GaAs) substrate, and via holes, were utilized to ensure single mode propagation (i.e., eliminating the parallel-plate mode or surface mode). To ensure the accuracy of the definition for the calibration kits, multi-line thru-reflect-line (MTRL) assistant standards were also fabricated on the same wafer and measured. The same wafer also contained passive and active devices, which were measured subject to both 16-term and conventional line-reflect-reflect-match calibrations. Measurement results show that 16-term calibration kits are capable of determining the cross-talk more accurately. Other typical calibration techniques were also implemented using the standards on the GCPW calibration kits, and were compared with the MTRL calibration using a passive device under test. This revealed that the proposed GCPW GaAs calibration substrate could be a feasible alternative to conventional CPW impedance standard substrates, for on-wafer measurements at W-band and above.