Improving VNA measurement accuracy by including connector effects in the models of calibration standards

For years, measurement inconsistencies were observed between calibration methods, such as sliding load, TRL and offset short, especially at frequencies above 18GHz. Measurement repeatability was another frustrating experience for practitioners of high precision measurements, such as TRL calibration. The “connector effect” was discovered recently. It provided the framework that these measurement inconsistencies and repeatability can be explained. This paper will review the observed measurement issues, present the theoretical base of the connector effect and show how VNA measurement accuracy can be improved.