Electrooptic Measurements to Assess the Quality of Calibration Kit Design

Electromagnetic coupling between planar devices can degrade microwave calibrations and, consequently, the accuracy of a measurement. This letter describes measurement-based methods that can identify, assess, and visualize the electric field coupled between the adjacent planar calibration structures. The coupling within a printed circuit board (PCB)-based and an on-wafer impedance standard substrate is successfully demonstrated and analyzed up to 4 and 20 GHz, respectively, through S-parameter and electric-field measurements obtained using an electrooptic probing system.