| As the rapid development of wireless communication technology and the continuous evolution of the new terminal form,the miniaturization,low power,consumption and high performance of modern wireless communication terminals have become an inevitable trend.In modern wireless communication system,RF transceiver is the maximum power consumption module,while the RF power amplifier is most obvious in RF transceiver.Therefore,it is of great important to study and design the RF power amplifier with low power consumption,high efficiency and high integration.This paper briefly introduces the research background and significance of the thesis,and then summarizes the current situation and development trend of novel multiplex high efficiency RF power amplifier and Ultra-wideband(UWB)power amplifier.Finally,based on the theoretical study of RF power amplifier,two kinds of power amplifier circuits are proposed which are applied to the wireless local area network(WLAN)and ultra-wideband(UWB)system.The achievements of our paper are as follows:(1)A novel and high efficiency outphasing power amplifier circuit is proposed.The circuit is mainly composed of the two class-E branch power amplifier and a power combiner.The each branch of Class-E power amplifier is made up of two stage circuits.The current-reused technology is applied in drive stage,and the cascode structure is used in power stage.Thus,the branch power amplifier can achieve higher efficiency and output power.The power combiner is a non-isolated Chireix combiner,which avoids using the large isolation resistance and reduces the power loss.Meanwhile,the Chireix combiner can compensate the different phase angle of the two branchs by using the LC compensation element,and it can make sure the outphasing power amplifier obtaining the good power-combining and improve the linearity of the circuit.The simulation results show that the outphasing power amplifier exhibits saturation output power of 21.4dBm with 2.5V supply voltage,an average power added efficiency(PAE)of 29.9%,a power gain of 38.8dB and an output 1dB compression point of 18.1dBm.(2)A novel and low power ultra-wideband power amplifier circuit is proposed.This circuit is based on the two stage circuits to achieve full frequency band and low power consumption.Current-reused technology is applied to improve the power gain in the whole frequency band and reduce the DC loss in the drive stage.At the same time,a forward-body-bias-structure is added to the substrate end of the transistor,and the low power consumption is achieved by reducing the supply voltage;the cascode structure is used to improve the level of output power in power stage.In order to cover the whole bandwidth of UWB system,the input matching uses the T-type impedance transformation network to realize the low quality factor.Meanwhile,the RC AC-feedback-network is used to improve the gain flatness of whole frequency band in the input and output terminals.The simulation results show that the power amplifier achieves the saturation output power of 8dBm,an output IdB compression point of 4.3dBm,a power gain and gain flatness of 15±1dB,input and output reflection coefficients of below-6.5dB and-7.6dB respectively,while only consuming 14.4mW from a 0.9V power supply.The components of the circuit presented in this paper are realized by using 0.18?m CMOS process,and the simulation and optimization design are achieved by using Cadence and ADS respectively.Compared with the similar circuits in recent years,the two kinds of power amplifiers proposed in our paper have a superior performance,especially in terms of efficiency and power consumption. |
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