Broadband Noise System Allows Measurements According to Both Standard Methods

A system that completely characterizes the noise temperature of a linear two-port over the 100-MHz-2.9-GHz band is presented. The system is based on a “long” transmission line and frequency variation. It allows measurements through the classical y -factor method or the more recent “cold” method. When applying the y-factor method, the system uses a broadband mismatched noise source and an autocalibration feature. To check the accuracy, a passive device is measured with its noise parameters computed from the S-parameters. The results produced by both methods are compared together and with respect to the values derived from the S-parameters.