Time-domain network analysis of MM-wave circuits based on a photoconductive probe sampling technique

A photoconductive probe sampling technique with 2-ps temporal resolution and microvolt sensitivity has been developed. The photoconductive probe sampling technique combines the ultrafast optical technology of the 120-fs Ti-sapphire short pulse laser and the microfabrication technology of the silicon-on-sapphire photoconductive sampling probe, which consists of a high-impedance interdigitated photoconductive switch. This technique can be applied to the measurement of the S-parameters of millimeter-wave circuit components with a 120-GHz measurement bandwidth. The probe technology was applied to the characterization of millimeter-wave band-block filters used in InP-based heterostructure MMICs (monolithic microwave integrated circuits) for 90-GHz to 180-GHz frequency doubling. Millimeter-wave delay lines have also been characterized, and the properties of transmission lines on thin semiconductor substrates have been studied.<>