How do I measure noise parameters of a transistor using a tuner-based noise figure measurement system?

Measuring the noise parameters of a transistor using a tuner-based noise figure measurement system involves presenting multiple known source impedances to the device under test (DUT) and measuring the noise figure at each impedance state, then fitting the four noise parameters (NF_min, Gamma_opt_real, Gamma_opt_imag, R_n) to the measured data. The measurement setup consists of: a noise source (calibrated excess noise ratio (ENR) source, typically 5-15 dB ENR), a programmable source impedance tuner (mechanical slide-screw tuner or electronic solid-state tuner that can present impedance states distributed across the Smith chart; the tuner's S-parameters must be precisely characterized at each state), the DUT (transistor mounted on a test fixture or in a probe station for on-wafer measurement), and a noise figure analyzer or spectrum analyzer with noise figure personality (measures Y-factor at each tuner state to determine the noise figure). The measurement procedure is: calibrate the noise source ENR, characterize the tuner's S-parameters at all impedance states using a VNA, set the first tuner state and measure the DUT noise figure using the Y-factor method (NF = ENR / (Y - 1) where Y = P_noise_on / P_noise_off), repeat for 8-32 impedance states distributed across the Smith chart (more states improve fitting accuracy), and finally fit the four noise parameters to the measured NF vs. Gamma_s data using a least-squares algorithm.