Broadband Differential On-wafer Measurements: challenges in de-embedding, drive control and related aspects

As at lower mm-wave frequencies, differential devices are commonly used for efficiency, noise, real estate and other reasons and their characterization is increasingly important over broadband frequencies (to >110 GHz). As GSGSG probes (and sometimes GSSG structures) are used, the coupling behavior becomes a more significant challenge at higher frequencies for calibration accuracy (behavior of the calibration lines), de-embedding and details of signal control. With an eye towards de-embedding extraction, calibration leakage corrections can be important and some approaches and calibration structures will be reviewed. Different methods for extraction/de-embedding balanced feed structures will be explored in this talk.