Differential Probe Characterization

In this paper, a novel probe without ground pins is proposed for differential signal measurement. An effective model for the differential probe is built in CST based on measured dimensions. To evaluate the electrical performance of the differential probe, a 4-port measurement is performed for a 1 inch differential pair using the probes. Simulation and measurement results match closely which further verifies the accuracy of the simulation model of both the differential probe and PCB under test. Guidance for launching footprint optimization of the differential probe can be extracted based on the sensitivity analysis results in terms of signal pad size, ground via size and ground pad size of the differential probes. Furthermore, loop inductance of the differential probe is evaluated from both 1-port measurement and simulation results.