Test vs. model correlation study on return loss characteristics of an emulated 25Gbps+ backplane system EMI source

As data communication rates are increasing, the possibility of EM emission from equipment becomes more significant and the task of EMI suppression becomes more challenging. Traditional approaches in addressing EMI/EMC issues are not very efficient and cost effective since the compliance tests are usually performed after the systems are fully developed, which may be at extremely high risk of adding development cost and delaying market introduction. To reduce the new product development risk and cost, using an effective 3D numerical simulation tool for modelling EM emission from 25Gbps systems in earlier design stage has been investigated in our previous work. Emission correlation study demonstrated a reasonable accuracy in our modelling tool and methodology. While in most design environment, the standard 3-meter Chamber and testing facilities may not be available. In present work, we further extend and focus our research to examine the return loss correlation between the measurements and simulation of an emulated 25Gbps+ emission source. Focusing on return loss rather than far field radiation, we may use a more controlled test methodology to study the modelling effectiveness accurately. This work is done in two phases, 1) return loss correlation between the model and test results for a fabricated broadband emission source, and 2) correlation between models versus test results with the emitter enclosed in a metallic box.