Improved multimode calibration standards for 40 GHz measurements of active devices

A set of calibration standards including multiple reflects is demonstrated for performing multimode thru-reflect-line (MTRL) calibrations. The measured multimode propagation characteristics for these lines are shown and the accuracy of the calibration using a particular reflect standard is demonstrated to 40 GHz. Small-signal multimode S-parameter measurements of a power amplifier demonstrate the value of the measurements for providing differential results including the common-mode rejection and mode-conversion parameters.