4～8GHz宽带单片集成低噪声放大器设计

摘要

A C-Band broadband monolithic low noise amplifier is designed based on 0.15 μm GaAs PHEMT process.The circuit is formed by cascading three stages of amplifiers.To solve the problem of complex power supply,each of the stage uses a self-biased resistance to achieve a single power supply.It not only ensures PHEMT to work at an optimum operation point with low noise and high gain,but integrates all components（including the bias circuit） in a monolithic GaAs substrate also.A parallel negative feedback structure is used in the third stage of the circuit to reduce gain of the low-frequency band and raise gain of the high-frequency band,which improves the gain flatness of the amplifier.Results from simulation based on AWR Microwave Office show that the designed LNA has a noise figure（NF） below 1.4 dB,a power gain of 23 dB,a gain flatness of less than ±0.5 dB and input and output VSWR of less than 2.0 over the frequency range of 4～8 GHz.%基于0.15μm GaAs PHEMT工艺设计了一款C波段宽带单片集成低噪声放大器。电路由三级放大器级联而成,三级电路结构均使用电阻自偏压技术来实现单电源供电,它既可保证PHEMT管处于低噪声高增益的工作点,又可将所有元器件集成在单片GaAs衬底上,解决了供电复杂的问题。第三级电路采用了并联负反馈结构,降低了带内低频端增益,提高了高频端增益,从而改善了增益平坦度。利用微波仿真软件AWR对电路进行了仿真和优化,结果显示,在4～8 GHz频带内,噪声系数〈1.4 dB,增益达23±0.5 dB,输入输出驻波比〈2.0∶1