The Multistate Radiometer: A Novel Means for Broadband Noise and Small-Signal Characterization of Microwave Semiconductor Devices

A novel noise approach to simultaneous noise and small-signal characterization of microwave semiconductor devices is presented. It is called the multistate radiometry and implemented in an original noise measurement instrument, the multistate radiometer (MSR). Before measurement, the MSR must be calibrated. This can be realized using the cold-source technique with at least six impedance standards at room temperature and one hot noise temperature standard. After that, an accuracy enhancement technique, applied to the measured data, yields the noise temperature and the impedance of one-port device. In consequence, the MSR has the potential of broadband automatic measurements carried out at a very low-power excitation from natural noise sources. The paper shows how this capability can be extended for two-port devices as transistors and MMICs, thus bearing their noise and scattering parameters. Experimental results presented for a Schottky mixer diode and a GaAs FET validate this new approach.