应用于802.11b无线局域网的低噪声高线性度的CMOS射频接收机

实现了一个单片集成、直接转换结构的2.4GHz CMOS接收机.这个正交接收机作为低成本方案应用于802.11b无线局域网系统,所处理的数据传输率为该系统的最大速率--11Mbps.基于系统设计以及低噪声高线性度考虑,设计了低噪声放大器、直接转换混频器、增益可变放大器、低通滤波器、直流失调抵消电路及其他辅助电路.该芯片采用中芯国际0.18μm 1p6m RF CMOS工艺流片.所测的接收机性能如下:噪声系数为4.1dB,高增益设置下低噪声放大器与混频器的输入三阶交调点为-7.5dBm,整个接收机的输入三阶交调点为-14dBm,相邻信道干扰抑制能力在距中心频率30MHz处达到53dBc,输出直流失调电压小于5mV.该接收机采用1.8V电源电压,I,Q两路消耗的总电流为44mA.

A Low Noise, High Linearity CMOS Receiver for 802. 11b WLAN Applications

A 2.4GHz monolithic CMOS receiver with direct-conversion architecture is presented. This quadrature receiver is designed for 802. 11b wireless LAN applications at the maximum data rate of 11Mbps as a low-cost solution. Five key blocks, i, e., a low noise amplifier (LNA), a down-conversion mixer, a variable gain amplifier, a low pass filter, and a DC-offset cancellation circuit, are designed based on system design and low noise high linearity considerations. The necessary auxiliary circuits are also included. Fabricated in SMIC 0.18μm lp6m RF CMOS process, the receiver's performance is measured as:4,1dB noise figure, - 7.5dBm input third order intercept point (IIP3) for LNA& mixer at high gain setting, -14dBm IIP3 for the whole receiver,53dBc @30MHz offset of adjacent channel power rejection, and less than 5mV output DC-offset. The receiver consumes 44mA under a 1.8V power supply with I,Q two paths.