An accurate calibration method of microwave noise sources using noise wave de-embedding techniques

We present a rigorous procedure for calibrating the Excess Noise Ratio (ENR) of microwave noise sources based on noise wave de-embedding techniques. The test and reference sources are connected to a wideband power combiner feeding a low noise amplifier preceded by an attenuator. The expressions for the measured Y-factors are derived from the noise correlation matrices and the S-parameters of the power combiner and attenuator. The power combiner is expected to limit any measurement uncertainties because of its symmetry. A cyclical calibration procedure is used to demonstrate that this calibration method introduces ENR calibration uncertainties below 0.025 dB.