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A novel high-Q on-chip inductor structure called suspending inductor is developed to improve the characteristics of the conventional on-chip spiral inductor. The suspending inductor employs the air gap and is supported by a set of novel metal pillars to suppress the capacitance from the metal layer to the substrate. The measured maximum quality factor of the suspending inductor is improved from 4.8 to 6.3 in comparison to the conventional spiral inductor. Furthermore, the frequency at maximum quality factor is raised from 1.5-2 GHz.