Evaluating The Suitability Of OSP Connectors For Calibration Kit Use

By Paul R. Pino, W. L.Gore & Associates

Introduction
Resulting from a lack of strict adherence to IEEE 287 general precision connector/ laboratory precision connector specifications (GPC/LPC), the Omni-Spectra push-on (OSP) connector type is not generally considered to be suitable for calibration kit use. Although this is the dominant opinion among microwave connector and metrology experts, data that either disputes or confirms this assertion is not readily available. Therefore, the purpose of this study is to answer the following questions:

1. Do corrected measurements of an OSP-terminated device under test (DUT), made with an OSP calibration kit, produce less repeatable results as compared to the measurements of the same DUT type using 3.5-mm-to-OSP adapters and a 3.5 mm calibration kit? How does measurement repeatability behave over multiple calibrations with respect to these two calibration scenarios?

2. When using an OSP calibration kit to effect corrected measurements of an OSP-terminated DUT, do the resulting measurements reveal a properly corrected DUT-to-test system interface (assuming DUT connectors are "standard" OSP connectors)? In short, how does the corrected reference plane area appear in the time domain?

This article investigates the differences in vector network analyzer (VNA) measurement precision when using a non-precision interface calibration kit (OSP-based), as opposed to a precision interface calibration kit (3.5-mm-based) in conjunction with the use of OSP-to-3.5-mm adapters.