A high performance integrated balun for 60 GHz application in 65nm CMOS technology

This paper shows a new design approach that allows to integrate an efficient balun into mm-wave radio frequency integrated circuits (RFIC). The proposed device is an evolution of the simple transformer. Thanks to the modification on the device´s shape, the performance increases considerably, maintaining limited dimensions. The proposed balun shows a very good power division with only 0.5 dB of maximum amplitude imbalance within the whole band of interest and less than 10° phase imbalance around 60 GHz. The measurement campaign confirms the accuracy of the electromagnetic simulations and the behaviour of the device. The balun is implemented in ST Microelectronic´s 65nm bulk CMOS technology and is employed in a double balanced 60 GHz down-conversion mixer to provide the balanced LO and RF signal.