Accurate Characterization of Radiation from Interconnects on Interposer at mmWave Frequencies

An electromagnetic interference (EMI) assessment of mmWave interposers becomes increasingly important as the need for heterogeneous systems increases. However, the small size and complexity of these platforms make it more difficult to accurately measure them and, thus, a dedicated set-up to isolate the interposer’s emission is required. In this contribution, we first show experimentally that at mmWave frequencies surface waves originating on the interposer test vehicles may interact with the larger measurement board and severely impact the radiation pattern and maximum electric field strength. Second, a simulation study into the exact origins confirms these surface waves indeed to be at the heart of this issue and calls for appropriate measures in interposer design to prevent any EMI complications when integrating this component in a larger system.