Miniaturized 3-dimensional transformer design

Abstract

3-dimentional fully-symmetric transformers are proposed and realized in a standard CMOS technology. In contrast to their planar counterparts, the self resonant frequency (f(SR)) of the proposed architecture is improved by 26 % to 53 %, while the chip area is reduced by 40 % to 70 %. The coupling coefficient (K) can be up to 0.77 at 8 GHz in a two turn two layer architecture. Distributed capacitance model (DCM) of the 3-D transformer is also proposed f(SR) evaulation.