Gigahertz, Low-Cost Current Shunt with Retrofitting Capability for Characterization of Fast-Switching GaN Devices

A low-cost current shunt based on a flexible polyimide printed circuit board (PCB) design is presented. With low insertion inductance in the range of 300 pH and bandwidth in excess of 1 GHz, the design is suitable to be used for characterization of very fast GaN devices. Due to its very low thickness, it is possible to retroactively integrate the sensor into many existing designs that were not specifically prepared for current measurement. Thus, it offers an alternative to designing specific PCBs only for switching characterization.