Microwave Filter Design for Electromagnetic Near Field Probe Development

Electromagnetic near field measurement technologies [1] are not only for traditional EMI detection, but also getting into PI/SI/ESD applications in recent years. Especially, SiP technology was used in many high integrity products successfully. In order to observe inside the circuits in package level, the H-probe design [2] would be smaller for higher resolution. Golden samples design is present to provide controllable H field between different trace to trace spacing by fist-order 1/4 lambda coupled line of microwave filter. The design changes the coupled line spacing (S=1.5mm, 1.03mm, 0.56mm, 0.25mm, and 0.12mm) by adjusting the bandwidth (Delta= 0.008, Delta = 0.018, Delta = 0.05, Delta = 0.15, and Delta = 0.6) for different operating bandwidths of 3GHz central frequency. In this method, the stable radiation H field could be collected by coupling characteristic, and probe measurement resolution would be verified accurately by different bandwidths design. We test the H-probe of EMI by using different line spacing, and observed whether H filed of EMI measurement [3] meet the simulation result by 3D EM full-wave solver.