Modeling and experimental validation of interconnects with meshed power planes

This paper presents a Finite-Difference Time-Domain (FDTD) analysis of meshed power planes that exist in multilayer plastic packages. The structure is divided into unit cells, and the analysis is used to find an equivalent circuit. An ABCD matrix of a periodic meshed plane is derived based on the FDTD analysis of a unit cell. The Bloch impedance and characteristic equation are solved to find the line impedance. This combined electromagnetic and circuit solution optimizes the accuracy and computational efficiency of the analysis. Experimental validation using a plastic land grid array (PLGA) test coupon is used to determine the accuracy of the theoretical analysis. The test coupon consists of a meshed plane structure with traces running beneath both the solid and the gap areas of the plane. Time-domain reflectometry (TDR) is used to measure the effects of the plane geometry on the impedance and propagation characteristics of the trace.