High performance planar micro-transformer using novel crossover connection

In this paper a novel planar micro-transformer with high performance is presented. Non-uniform current density distribution, especially in inner turn, increases the effective metal resistance due to skin and proximity effect. In order to overcome this problem, a novel crossover connection between turns has been used to make equal current paths in the turns and uniform the current distribution. By reducing the current crowding effects, the effective resistance is minimized, thereby the transformer performance characteristics can be increased. Simulation has been taken using ADS Momentum and HFSS software. The results show that the quality factor, self-inductance, mutual inductance and coupling factor are about 42.6, 4.9, 3.3 nH, 0.747 respectively, at 3.5 GHz frequency. The footprint of proposed structure is 860 μm × 860 μm. Compare with conventional micro-transformer, 17% in quality factor, 5% in coupling coefficient and more than 20% in self and mutual inductance improvement has been achieved.