A Novel Doubly-Balanced Folded Mixer for Low Supply Voltage and Direct Up-Conversion System

A direct up-conversion mixer from 1MHz to 2.4GHz implemented by TSMC 0.18mum 1P6M CMOS process is demonstrated. In this design, the combination of the concepts of "active dual-gate mixer" and "passive FET mixer" is used to achieve mixing effect. With the "folded" structure, this mixer can operate at low voltage (1V) normally. As the results show, the conversion gain is 2.5dB at 0dBm of LO power and the P
_1db
is about -3.5dBm. At the same time, the isolations of LO/input and input/output are both more than 30dB, but the isolation of LO/output is about 10~20 dB