Modelling and design of high performance capacitors for CPW multi-chip modules

A new coplanar waveguide capacitor configuration is proposed for multilayer MCM design. Using the novel configuration a wide range of capacitors are designed and modelled, with a self-resonance frequency going to beyond 40 GHz. To increase the capacitance density and maintain high performance a number of pairs of parallel plates were employed horizontally. An empirical model is introduced to calculate the equivalent capacitance of the MCM capacitor directly and accurately, without EM simulation, from the capacitor electrodes dimensions and measurements on a capacitor. This formula even incorporates the effect of fabrication process on material properties, metal pattern definition high frequency phenomenon etc, which are very difficult to incorporate neither during EM simulation. This empirically derived formula predicts the equivalent capacitance of a wide range of fabricated capacitors very accurately directly from the electrode dimensions. An excellent agreement with the measured performance for a range of fabricated capacitors has been observed.