Noncontact internal probing of microwave integrated circuits

Abstract

A non-contact probing technique for non-invasively performing vector voltage measurements at the internal points of an operating microwave integrated circuit is presented. The internal voltage amplitude and phase are extracted by sensing the localized electrostatic force between a miniature probe and point in the circuit being measured. A force nulling approach allows accurate high frequency voltage measurements to be performed on without the need for complex calibration and on passivated circuits. The non-contact probe introduces a loading of less than 1fF at the test point.