Embedded capacitor design rules in multilayer organic-based substrate for HF circuits

Embedded capacitor technology has a great potential for improved electrical performances, assembly cost reduction and the circuits reliability increase for high frequencies applications. This article describes the behavior of embedded capacitors and studies the design rules in a wide frequency band. In a first time, a simple planar capacitor of (1*1) cm² surface is designed and simulated by 2.5D and 3D field solver software Momentum and HFSS respectively, in the range of 10 MHz to 1.2 GHz. The latter is compared by measurements results and shows a good agreement on the resonant frequency values (10%). In a second step, from the validated model, two 3D structures using capacitors sizes (1*1) mm² are studied in the band of 1 MHz to 10 GHz. In parallel, the electrical equivalent models of these structures are released by the ADS software. A smaller difference in resonant frequency (20%) is obtained to results simulations of 3D and electrical models. Finally, electromagnetic (EM) simulations on various geometries of capacitors for same surface electrodes and for buried structures, give a resonant frequency around 1.7 GHz.