Internal probing of mm-wave integrated circuits

There is currently no instrument capable of providing internal vector-voltage measurements of mm-wave integrated circuits. We present a non-contacting probe capable of non-invasive internal amplitude and phase measurement of high-frequency MMICs. Accurate and localized voltage measurements can be made without complex calibration and without depassivation of test points. A probe with a >26 GHz bandwidth, <10 fF loading, <10 mV amplitude and <2° phase resolution, and a μm spatial resolution is demonstrated.