I. Introduction
Over the past five years, the infrastructure for characterizing RF components has been extended well beyond the millimeterwave range and probes for on-wafer measurements up to 1 THz are now available [1]. This advance in probe technology to the submillimeter-wave region has been made possible through application of micromachining techniques that permit fully-integrated probe chips to be fabricated from high-resistivity silicon, a material that simultaneously satisfies the requirements for low-loss propagation and mechanical robustness [2]. Due to these properties, silicon, continues to receive significant attention as a packaging platform and substrate for heterogeneous integration of millimeter and submillimeter-wave components [3], with micromachined on-wafer probes containing integrated strain sensors [4] as well as balun circuitry for differential measurements [5] having been demonstrated in recent years.