Title: Accurate S-Parameter Measurements for PCB Channel Block Characterization

Abstract: Extracting high-quality S-parameters for a DUT from measurements inherently involves de-embedding them from a total structure that includes test fixture lead-ins.  These lead-ins typically include probes or connectors, and potentially some length of non-coaxial transmission-line, e.g., stripline or microstrip on a PCB, as well as via transitions, in addition to the DUT.  A common current de-embedding approach often used for DUTs on printed circuit boards, packages, and cabling for example, utilizes a 2X Thru, or 1X Open, together with the total structure to extract the DUT S-parameters.  For many current high-speed and high-frequency applications it is necessary to do 3D full-wave electromagnetic simulation in order to develop a high-quality test fixture from which successful de-embedding can result.  The features that comprise good lead-in test fixturing from which DUT S-parameters can be extracted will be detailed in this presentation.  EM simulation for developing test fixtures will be discussed and examples provided. This presentation will also discuss making quality S-parameter measurements with a VNA, and provide comparison results.  Examples to 50 GHz will be presented.