Abstract
This letter presents the design and analysis of the proposed hexagonal suspended toroidal inductors and the applications in a self-packaged low-loss low-pass filter (LPF). The characteristics of the proposed inductors are studied and analyzed with the developed <inline-formula> <tex-math notation="LaTeX">\pi </tex-math></inline-formula>-type equivalent circuit model. Compared to widely adopted spiral inductors, the proposed hexagonal suspended toroidal inductors feature improved quality factors (<inline-formula> <tex-math notation="LaTeX">Q </tex-math></inline-formula>-factors) in experimental verifications. Following the developed theory and equivalent circuit model, several suspended toroidal inductors are designed and applied to a 5th-order lump self-packaged LPF. The filter achieves the passband insertion losses of < 0.49 dB and return losses of <inline-formula> <tex-math notation="LaTeX">>14.7 </tex-math></inline-formula> dB, which demonstrate the advantages of high <inline-formula> <tex-math notation="LaTeX">Q </tex-math></inline-formula>-factor of the proposed inductor topology.