Calibration method for offset open

A new one-port impedance analyzer using a voltmeter/ammeter method has been developed for analysis of high frequency devices and materials up to 1.8 GHz. The analyzer requires a performance test periodically. One of the tests uses a 100 mm length beadless coaxial airline terminated by an offset open termination, as a one-port impedance standard. The offset open has an 8 mm length inner conductor supported by a dielectric material. This paper describes a calibration method for the offset open in the frequency range from 1 kHz to 2 GHz. The impedance of the offset open is calibrated with a precision 41 mm length coaxial beadless airline, a vector automatic network analyzer, and a 1 kHz precision capacitance bridge. Distributed resistance, inductance, and capacitance per unit length of the 41 mm length airline are derived from mechanical dimensions calibrated by Japan Quality Assurance Organization (JQA), formerly Japan Machinery and Metals Inspection Institute (JMI). As a result, the capacitance of the offset open is indirectly traceable to Japanese measurement standards