This paper aims to design a high-quality-factor suspending micro-inductor and to establish its equivalent circuit model for performance optimization. Two commercial software (Ansoft HFSS and Agilent ADS) are adopts to analysis the influences of quality factor on the geometric parameters and substrate materials. The designed micro-inductors are constructed by one bottom GSG electrode, two supporting copper vias and a spiral suspending copper conducting layer. As the simulated results of this research, the quality factor of the suspending micro-inductor is increased with the height of air gap, the thickness and width of suspending copper conducting layer and decrease with the number of turns, line space and outer diameter of suspending copper conducting layer. The influences of different shapes of the spiral suspending copper conducting layers on the quality factor of micro-inductors were also investigated. The simulation results well match to the theoretical prediction. Finally, this thesis has successfully derived two experiential formulas based on the analysis results to estimate quickly the inductance of the suspending micro-inductors with circular and square shape. Compared with the simulation results and realistic measurement results, these experiential formulas demonstrate 94-95% and 90% accuracies respectively.

For the application of 4G wireless communication system, this thesis aims to develop a high-quality-factor and low-power-dissipation suspending micro-inductor using electrochemical deposition and surface micromachining technologies. This research presents three technical points to improve the quality factor and reduce the power dissipation of micro inductor, including (i) to adopt a low resistivity material (copper) as the conducting layer to decrease the Eddy current due to the skin effect and reduce the total series resistance and energy loss, (ii) to utilize a suspending structure to diminish the power loss through the substrate and (iii) to replace the silicon wafer with a high resistance substrate (Corning 7740) to compress effectively the power dissipation in high frequency operation. The implemented suspending micro-inductors were characterized by a commercial network analyzer (Agilent E5071C) under 0.5~20 GHz testing frequency range. All the inductances and quality factors of the micro-inductors proposed in this thesis are extracted by the Agilent ADS software. The optimized value of the quality factor is around to 24.9 and the corresponding inductance is equal to 5.43 nH .