The Research And Design Of The Low Power RF Power Amplifier

The vast part of power consumption in modern wireless communication system comes from the RF front-end circuit,especially from the RF power amplifier.As the requirements for communication terminal is increasing,it is a tendency that the RF front-end system will be low cost,compactness and integration.As a consequence,it is of great importance to design a RF power amplifier with low power consumption and high integration.This paper briefly introduces the background and significance of RF power amplifier,and reviews the domestic and international research status of high efficient class-E power amplifier and Ultra-wideband(UWB)power amplifier.After much the literature reading and theoretical analysis,we put forward two kinds of power amplifier circuits aimed at lower power consumption,one is for the wireless local area network(WLAN),and the other is for the ultra-wideband(UWB)communication system.The achievements of this paper are as follows:(1)A new-type of high efficient class-E power amplifier is presented.The power amplifier is composed of two stage circuits.The current-reuse in the driver stage helps to achieve high gain and reduce the bias current.The power stage can increase output power by using Cascode self-biased technique.Besides,in order to eliminate the influence of the parasitic capacitance,the switch transistor inserts a series of LC network.It also improves the linearity of power amplifier.When the supply voltage is 2.5V,the simulation results are as follows:the power added efficiency(PAE)of the power amplifier is 68.3%,the output power is 21.5dBm,the power gain is 45dB;The input reflection coefficient is below-13.6dB in 2.4GHz;According to the parameters,we find that the amplifier has the character of high efficiency,high gain and high output power.(2)A low power UWB power amplifier is presented.The common gate transistor severs as an input matching network which makes the power amplifier achieve good input impedance matching in the range of 3.1?10.6GHz frequency band.The gain flatness performance of the full bandwidth is improved by adopting the RC feedback technique and the inductance peaking technique.In order to reduce power consumption,the power amplifier employs the body-bias technique which can change the threshold voltage of the transistor.The simulation results show that the maximum output power is 5.5dBm in full bandwidth of UWB,the power gain is 10.6±0.8dB,the output ldB compression point is 2dBm,the input/output reflection coefficients(S11,S22)are below-14.3dB and-9dB,respectively.When the supply voltage is 0.9V,the power consumption is only 14.3mW.The proposed circuits are simulated in TSMC 0.18?m CMOS technology by ADS and Cadence software.