该文提出了一种应用于WLAN相位可调的本振缓冲器,用于校准直接下变频收发机的I/Q两路不平衡。该电路通过开关输入MOS管源极的电容阵列,延迟本振信号,从而调节信号的相位。该文采用SMIC0.18μm工艺实现了4.8~6GHz的I/Q两路本振缓冲器的设计,其版图面积为650×550μm^2。仿真结果表明,在5位控制字作用下,I或者Q路本振缓冲器的相移在0~8°的范围内呈现近乎线性的变化,而本振缓冲器的输出功率的变化范围只有0.2dB。
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 650×550μm. 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.