A CMOS Full-Cycle Mixing Vector Modulator

This letter presents a new vector modulator architecture which makes full use of the baseband signals when performing signal mixing to enhance the already improved conversion gain of the mixers which use the local oscillator signals (LOs) of 25-percent duty cycle. The proposed technique can increases the signal conversion gain by 3 dB theoretically. The 2.4 GHz fully-integrated modulator is developed by using the commercial 90-nm CMOS process and the chip size is 0.74 mm × 0.74 mm. The measured image rejection ratio and carrier feed-through are -52 dBc and -58 dBc, respectively. The CMOS vector modulator is measured passing the spectrum mask test of the IEEE 802.11b/g/n WLAN standards and achieves the EVMs of 3.8% for 802.11g and 2.6% for 802.11n.