Design and Modeling of Miniaturized Band Gap Structure for Wideband GHz-Noise Suppression Based on LTCC Technology

A novel electromagnetic band gap (EBG) structure as a component is proposed for broadband suppression of GHz simultaneous switching noise. The structure is composed of three-dimensional interdigital capacitors (3D-IDC) and series U-shaped transmission lines periodically. The EBG structure can be miniaturized based on the LTCC fabrication technology. A theoretical circuit model which considers the inductive coupling in the 3D-IDC will be developed to predict the stop band. The accuracy of the proposed model will be verified by comparing with both the full-wave simulation and the measurement results. This modeling method is also employed to study the variation of band gap dependent on different geometrical parameters for the 3D-IDC and the U-shaped transmission line. A prototype is implemented using the LTCC technology with the dimension 1.2mm?3.8mm?0.728mm. Both simulation and measurement show the rejection band is from 2GHz to 5.5GHz. Over 25dB noise reduction in the stop band could be achieved. In addition, the suppressive ability is also verified in the chip-package co-simulation. From the simulation result, significant reduction of power noise could be found both in digital and mixed signal circuits.