Robust CMOS Micromachined Inductors With Structure Supports for Gilbert Mixer Matching Circuits

In this brief, three novel structure supports for on-chip CMOS-based micromachined inductors are proposed to improve mechanical stability. The inductors are fabricated using a two-step maskless post-CMOS process. A 3-D electromagnetic inductor simulation model is established for performance analysis of the inductors before fabrication. The proposed inductors are applied in the matching network of the double-balanced Gilbert mixer to improve the performance and mechanical reliability for mobile communication. The mixers with and without micromachined process inductors are fabricated in a 0.5-mum CMOS process. The measurement results show an 18.6% increase in the conversion gain, a 31.7% improvement in the third intercept point (IIP3), and a 25.3% reduction in the noise figure.