Broadband characterization of miniaturized on-chip differential circuits using G-S-G probe

An approach is presented to characterize on-chip differential coplanar-strip-line (CPS) test circuits using G-S-G probes. This probe convert signal from either a coaxial connector or waveguide into the test circuit under test to achieve impedance matching and field pattern matching. With a symmetric duplicate of the test circuit in shunt connection, the circuit can be characterized over a wide frequency range. This method is especially effective to miniaturized circuits. A 40-GHz silicon-based filter is employed for demonstration.