Using a Load Tuner to Improve the Accuracy of Noise Characterization

In principle, the noise figure of any microwave device is independent of load impedance; however, because of error sensitivities, a load tuner is required to achieve best noise measurement accuracy. This is because a high ouput reflection coefficient of a device under test can greatly increase the measurement receiver noise figure. This paper also presents a direct method of detecting and avoiding oscillations due to simultaneous input and output tuning.