Calibrated Tuner for Chip Characterization Above 18 GHz

A device which produces a known, mechanically-variable impedance and is useful for noise parameter or power load-pull measurements is described. The device integrates a three-stub waveguide tuner, a waveguide-to-microstrip adapter, a DC bias tee, and a removable chip-carrier into one compact unit. The design features a high degree of tuner repeatability, electrical readout of stub length, ease of calibration due to an accurately analyzable tuner structure, and operation at cryogenic temperatures if desired. The calibration procedure and a prototype unit operating in the 18-26.5 GHz band are described along with sample transistor noise parameter measurements.