A method for the complex residual errors of a VNA in one-port measurements

This paper shows that a method using multiple air lines for estimating the complex residual errors of a VNA (Vector Network Analyzer) being calibrated by an `OSL´ (Open-Short-Load) technique, which is widely used for one-port measurements, can be applied to the case when an adapter should be used for the connection of air lines and calibration standards. It uses a simple circle fit algorithm, together with some techniques to be used for improving the accuracy in finding the center and radius of a circle in the complex reflection coefficient plane from measured calibration data.