In this paper a novel method to design a miniaturized Marchand Balun is proposed. The main issue in the balun design is to limit its physical dimension. This work shows a device that achieves good performance, in terms of phase and amplitude balance, and reduced size at the same time. To allow such a result, an accurate analysis of the electromagnetics phenomena was done. The principal equations that characterize the structure are resumed in the paper. The device has been fabricated in 65 nm CMOS technology. The balun has been designed for application in a wide band low power 60 GHz transceiver.