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

In this paper, a modified-T equivalent-circuit model for three-dimensional (3-D) spiral inductors embedded in a multilayer low-temperature cofired ceramic (LTCC) is first presented to achieve 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 electrical length up to /spl pi/, and several resonators to consider the effects due to coil coupling and 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 /spl Pi/-section model that is valid only up to the first self resonant frequency (SRF), this model includes more higher-order SRFs and results in a several times larger bandwidth.