DC-to-mm-wave absolute potential measurements inside digital microwave ICs using a micromachined photoconductive sampling probe

A micromachined photoconductive sampling probe is used to determine detailed wave forms at different circuit nodes and corresponding propagation delays from within an InP HBT frequency divider operating at 2.7 GHz. The results demonstrate for the first time the capability of photoconductive probes for absolute-voltage, DC-coupled potential measurements in integrated circuits.