Research On High Linearity Wideband Low Noise Amplifier

With the rapid development of the wireless communication technology,various wireless communication standards have been proposed and employed in the market,Moreover,with the emerging of the “Internet of Things”(IoT),there is an urgent demand in the design of high-quality multi-standard and multi-band communication equipment in the near future.Therefore,the research on the wideband RF front-end module which has the ability to cover the frequency range of the majority communication standards has aroused great interest in recent years.However,the increasing number of communication standards significantly narrows down the margin between different frequency bands,leading to a more serious interference between the signals of adjacent frequency band.In order to maintain a high-quality input signal for the microprocessor,it is essential to further improve the linearity of the RF front-end module to a higher level.Since the low noise amplifier(LNA)is typically at the first stage of the RF receiver,the overall linearity of the RF receiver is greatly determined by the performance of LNA,and thus it is worth careful designing.Motivated by this,this work focuses on the design of a high-performance LNA which can not only capable for various communication protocols,but also maintain a high linearity at the same time.All the designs of this work are based on TSMC 65 nm technology.Starting from the analysis of the performance parameters such as noise figure and linearity,the widely used topologies and linearization techniques of the wide-band LNA are introduced and compared in detail.Based on the comprehensive analysis,an on-chip feedforward technique is proposed in this work to improve the performance.Without adding any extra passive devices,the off-chip matching network and the scaling factor circuit in the conventional feedforward method are replaced by the proposed on-chip circuits,making the whole system integrated on chip.In addition,considering the PVT sensitivity of the feedforward technique,an adaptive PVT calibration circuit,based on least mean square algorithm,is proposed in this work.The simulation results show that the calibrated circuit maintains high stability at corner FF,TT,SS and temperature-40,27,125.Finally,the proposed adaptive distortion cancellation LNA shows 17.2dB maximum gain,5.03 dB maximum noise figure,and a reflection figure below-12 dB in a wide-band from 300 MHz to 4GHz.Moreover,the IIP2/IIP3 of the whole system is larger than 21.8/15.2dBm in the propose band.