1MHz～40GHz超宽带分布式低噪声放大器设计

为满足宽带系统中低噪声放大器(LNA)宽带的要求,采用0.15μm GaAs赝配高电子迁移率晶体管(PHEMT)工艺,设计了两款1 MHz^40 GHz的超宽带LNA,分别采用均匀分布式放大器结构及渐变分布式放大器结构,电路面积分别为1.8 mm×0.85 mm和1.8 mm×0.8 mm。电磁场仿真结果表明,1 MHz^40 GHz频率范围内,均匀分布式LNA增益为15.3 dB,增益平坦度为2 dB,噪声系数小于5.1 dB;渐变分布式LNA增益为14.16 dB,增益平坦度为1.74 dB,噪声系数小于3.9 dB。渐变分布式LNA较均匀分布式LNA,显著地改善了增益平坦度、噪声性能和群延时特性。

Design of the 1 MHz-40 GHz Ultra-Wideband Distributed Low Noise Amplifier

In order to meet the broadband requirements of lownoise amplifiers(LNAs) in broadband systems, two ultra-wideband LNAs from 1 MHz to 40 GHz were designed with 0.15 μm GaAs pseudomorphic high electron mobility transistor(PHEMT) process. The uniform distributed amplifier structure and the tapered distributed amplifier structure were adopted respectively with the circuit areas of 1.8 mm×0.85 mm and 1.8 mm×0.8 mm, respectively. The electromagnetic field simulation results show that in the frequency range of 1 MHz to 40 GHz, the uniform distributed LNA has a gain of 15.3 dB, a gain flatness of 2 dB and a noise figure of less than 5.1 dB;and the tapered distributed LNA has a gain of 14.16 dB, a gain flatness of 1.74 dB, and a noise figure of less than 3.9 dB. Compared with the uniform distributed LNA, the tapered distributed LNA significantly improves the gain flatness, noise performance and group delay characteristics.