Development of 5.5-GHz band pass filter in all silicon multilayer substrate with air dielectric

A compact 5.5-GHz band pass filter (BPF) with 12.7% 3-dB bandwidth is developed in an all silicon multilayer substrate with air dielectric incorporated for WiMax applications. The topology of the BPF is a capacitively coupled fifth-order Chebyshev BPF. Its volume is 9.3 × 8.5 × 0.6 mm³. Two design aspects - air dielectric and through silicon via (TSV) technology integration - play an essential role in the BPF implementation. The spiral inductor with an integrated air dielectric has quality factor and self-resonant frequency improvement of 112 and 41%, respectively. The TSVs in the BPF design enables the implementation of two-layer inductors with a low value of inductance. The volume of TSV in the two-layer inductor is 75 × 75 × 200 μm³ and its inductance is 0.15 nH at 5 GHz.