Simulation of Feedforward RF Amplifier
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摘要: 为了满足现代无线通信对放大器线性度的要求,需要对射频放大器的线性度进行优化.讨论了前馈技术的原理和方法。并用ADS软件进行了仿真,利用前馈技术优化的放大器,线性度改善了40dB以上,表明前馈技术对改善放大器的线性度效果明显。Abstract: Modern wireless telecommunication requires high linearity of radiofrequency amplifiers.Feedforward technique is the most effective and sometimes the only one that can improve the linearity to satisfy the system demands.It improves the linearity of an amplifier through the following three steps,extracting the nonlinear distorted component from the output of the amplifier,adjusting the amplitude and phase of this nonlinear distorted component to obtain the same amplitude and opposite phase as the distorted component of the amplifier output,and counteracting the distorted component by summing up the adjusted nonlinear distorted component and the amplifier output.ADS is one of the most popular software for radiofrequency circuitry design.Its simulation results can reflect the characteristics of circuits correctly.In this paper,we elaborate the basic theories and methods of feedforward technique.Then we simulate a feedforward amplifier by using ADS software.The simulation shows that the third-order intermodulation component has been improved by more than 40 dB.The result of the present study suggests that the effectivity of the feedforward technique improves the linearity of amplifiers.
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Keywords:
- radio frequency amplifier /
- feedforward /
- linearity
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