Research On Key Technologies For Wide Band Power Amplifiers

With the development of semiconductor technology and wireless communications,high-speed,high-capacity,low-cost information transmission has become the goal,which promotes the development of key technologies such as broadband,high-gain flatness,high power and high efficiency.As the core component of the RF transmission system,the performance of the power amplifier is critical to the performance of the entire transceiver system.In recent years,the rapid development of wireless communication technology has driven the demand for chips with superior performance,leading to the increased use of GaAs technology in RF integrated circuits and the advancement of research on GaAs power amplifiers.In addition,broadband has become a core technology for high-speed information transmission,making broadband power amplifiers in high demand.Consequently,this thesis focuses on the key technologies of gain flatness,high power and high efficiency of broadband microwave power amplifiers and presents the following primary research work and contributions:1.To overcome the challenge of a high imaginary part of the input impedance leading to difficulties in broadband matching,a lossy network and a double-L matching structure were employed to suppress the frequency variation characteristics of the input impedance and reduce the difficulties in broadband matching.Based on this approach,a 12-18 GHz power amplifier was developed using 0.5 μm GaAs p HEMT technology.The measured results showed that the circuit achieved a small-signal gain of 15.7 d B and a saturated output power of 23 d Bm,thus verifying the feasibility of the proposed method for reducing the difficulty of broadband matching.2.To address the problem of gain flatness in broadband power amplifiers,a gain distribution compensation technique is proposed that solves the gain flatness problem at broadband operating frequencies.Based on this,a 4.5-8.5GHz power amplifier is fabricated using 0.5um GaAs p HEMT process technology.Measurement results show the gain of 22.6±0.8d B and the saturated output power of 25 d Bm within the bandwidth,confirming the effectiveness of the proposed gain distribution compensation technique.3.This thesis presents a distributed amplifier operating from 2-18 GHz based on0.1 um GaAs p HEMT technology.To overcome the problem of low output power in ultra-wideband power amplifiers,a stacked distributed structure is employed to increase the output power of this amplifier.Simulation results show that the amplifier achieves 2W output power and more than 15 d B power gain within the operating bandwidth.4.To address the problem of low efficiency in ultra-wideband power amplifiers,an impedance inversion compensation technique is proposed that solves the problem of low efficiency in distributed power amplifiers.Based on this technique,a 2-18 GHz amplifier is designed using 0.1um GaAs p HEMT technology.Simulation results show that the Peak Power Added Efficiency(PAE)is greater than 40% over the bandwidth,verifying the effectiveness of the proposed impedance inversion rotation compensation technique.