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 π, 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.