A LO Buffer with Tunable I/Q Phase for WLAN
一种应用于WLAN相位可调的本振缓冲器

This paper presents a Local Osicillator (LO) buffer for WLAN which can tune the I/Q phase of the LO signal in order to calibrate IQ imbalance in direct conversion transceiver. It can tune the phase by means of switching the MOS capacitor array to delay the LO signal. It is implemented in SMIC 0.18μm, the layout of 4.8~6GHz I/Q LO buffer occupies a total die area of 650×550μm2. Post simulation shows that the phase shift of the I or Q LO buffer varies almost linearly from 0° to 8° with the action of 5bit control word, whereas the output power of the LO buffer varies within 0.2 dB.