Development of suspended planar two port micro transformer for RF wireless application

In order to improve the quality-factor and magnetic coupling factor of micro transformer at high operating frequency, this paper presents two-port micro transformer utilizing micro-electro-mechanical systems (MEMS) technology are featured with very small chip size (0.7 mm×0.7 mm×0.5 mm) and constructed of a 0.32 μm-thick TaN/Ta/Cu bottom electrode, 10 μm-height supporting copper via, and a 6 μm-thick suspended spiral copper conducting layer with 10 μm air gap. Measurement results show the implemented two-port micro transformer demonstrates very high magnetic coupling factor (0.78) and quality-factor (17.2) at 5.2 GHz operating frequency.