一种无线体域网发射机体偏置线性化技术

该文针对无线体域网人体介质通信(Human Body Communication, HBC)发射机严格的输出频谱指标，提出一种利用体偏置线性化技术进行频谱整形的技术。通过设计缓冲器中晶体管体偏置，从而调整晶体管二阶非线性系数，最终消除输出端的二阶互调项(Second order InterModulation, IM2)。采用0.35 m CMOS工艺和1.8 V供电电压设计了一个基于体偏置技术的HBC发射机实例。仿真结果显示二阶输入截点(IIP2)优化到 90 dBm，输出频谱在1 MHz处抑制-130 dBr。较传统电路，该技术提高了23 dB频谱抑制，使输出频谱符合无线体域网IEEE 802.15.6协议中-120 dBr的指标。

Body Biasing Linearization Technique for Wireless Body Area Network Transmitter

A body biasing linearization technique is proposed to shape output spectrum mask to meet the stringent specification of the Human Body Communication (HBC) standard for Wireless Body Area Network (WBAN). Body biasing of the buffer transistors is properly designed, accordingly second-order nonlinearity coefficient is tuned so that Second order InterModulation product (IM2) at the output of buffer is cancelled. Under 0.35 m CMOS process and a supply voltage of 1.8 V, a sample HBC transmitter based on body biasing is designed. Simulation results show that an optimum of 90 dBm IIP2 can be obtained and output transmit spectral mask at 1 MHz is attenuated to be -130 dBr (dB relative to the center frequency). Compared with conventional circuits, an improvement of 23 dB spectrum attenuation is achieved, satisfying the -120 dBr requirement of IEEE 802.15.6 for WBAN.