Anomalous RF Propagations of a IIIV Flip-Chip onto a CPW Substrate

Mounting IIIV-based RF chips and components onto a substrate that constitutes a large RF system in the order of several operating wavelengths (even to a greater extent) often spawns anomalous RF propagations, which will be discussed and analyzed in the paper. The investigation begins with a conductor-backed CPW (co-planar waveguide), which electrically shorts two large surface ground planes to a bottom ground plane, and shows negligible RF leakage residing in the ground plane. Then the RF chip is flipped facedown to the CB-CPW for RF interconnection, showing the existence of resonance and the coupling behavior throughout the package. The three-dimensional iso-surface field displays of the standing wave patterns enable a better physical insight of the anomalous propagation effects and a proper assessment of their impact on the RF system.