A parametric layout study of radiated emission from high-frequency half-bridge switching cells

We present a numerical modeling study of radiated emission from half-bridge switching cells based on the method of moments (MoM). A low loop inductance cell design enables high-speed switching of power semiconductors which is demonstrated on a prototype circuit. The layout is further optimized for low radiated emission by variation of the heat sink placement. This is achieved by the heat sink attached to the phase terminal. The performance of the structure in terms of loop impedance, electric field radiation and sensitivity to cable attachments are numerically studied. Emission peaks arising from loop resonances can be reduced by over 20dB with damping elements in the switching cell. The improved EMI performance of the proposed structure is attributed to decoupling of the loop current from the heat sink structure.