Investigating scattering parameters measurements for 50GHz highspeed Printed Circuit Boards (PCBs)

This paper describes some investigations, made using coaxial launch connectors and microwave probes, into the scattering parameters (S-parameters) measurements for a highspeed Printed Circuit Boards (PCBs) by using Vector Network Analyzers (VNAs) operating at microwave frequency up to 50GHz. The grounded Coplanar Waveguide (GCPW) transmission line with Electromagnetic Band Gap (EBG) in ground planes as one reference standard for S-parameters of the general high-speed PCBs, of which characteristic impedance is 50 ohm, is predicted and analyzed from electromagnetic theory. The paper describes the impedance standard in detail and compares experimental results, obtained using a VNA operating in the 10MHz to 50GHz band, with values predicted by electromagnetic modeling software. The measurement is implemented after using Multiline Thru-Reflect-Line (Multi-TRL) algorithm by Wincal XE4.5. The impedance mismatch is analyzed by Time-domain Reflection (TDR) method.