A novel modified-T equivalent circuit for modeling LTCC embedded inductors with a large bandwidth

This paper presents a new modified-T model for three-dimensional inductors embedded in the multilayer low-temperature cofired-ceramic substrate with a remarkably large bandwidth. This model combines a core circuit, a five-element modified-T model, to include the effects of a transmission line with an electrical length up to /spl pi/, and several resonators to consider the effects due to coil coupling and the finite ground plane. It is emphasized that most of the elements in this equivalent-circuit model can be extracted directly from the measured S-parameters. Compared to the conventional PI-section model that is valid only up to the fundamental self resonant frequency (SRF), this model can include more higher-order SRFs and ground resonant frequencies effectively, which results in several times larger bandwidth.