K频段集成化低噪声接收组件

【作者】 杨晶晶；

【导师】 肖泽龙；

【作者基本信息】 南京理工大学 ， 通信与信息系统， 2010， 硕士

【摘要】 卫星接收系统前端电路是卫星通信系统中的一个重要部件,本文设计了K波段接收机射频前端中的关键电路,主要包括波导-微带转换器,低噪声放大器,镜像抑制滤波器,混频器和中频低通滤波器。最终实现的系统电路增益达到了29 dB,噪声系数小于2dB。整体电路的尺寸为77.3mm×16.7mm,实现了集成化。本文分析设计了两种不同结构的K波段波导一微带转换器,这两种过渡结构都是利用同轴探针制作的。实验结果表明：两种波导-微带转换器的插入损耗均小于0.06dB。低噪声放大器选择两级HEMT(高电子迁移率晶体管)晶体管和一级MMIC芯片实现,最终实现的低噪声放大器的噪声系数小于1.1dB,增益大于39dB,增益平坦度小于1dB。利用平行耦合微带结构设计的镜像抑制滤波器在工作频段内回波损耗大于14dB,在镜像频率处的抑制大于60dB。微波混频器的设计,选择了Skyworks公司的肖特基势垒二极管,设计了一个微波单平衡混频器,并给出了该混频器的仿真设计过程和结果。设计的混频器的变频损耗小于8.7dB,各端口隔离度均大于20dB。本文的电路设计采用Agilent ADS和HFSS对设计的电路进行设计、仿真、优化,从测试的结果看,设计完全满足系统设计指标的要求。更多还原

【Abstract】 The front-end circuit is a very important part in satellite communication systems. In this paper, we design some key circuits of the K-band front-end circuit,including the waveguide-to-microstrip transition, a low noise amplifier，a image-reject band-pass filter,a mixer and a low-pass filter.The system designed in this paper has a gain up to 29 dB and the noise figure is less than 2dB. The size of the overall circuit is 77.3mm×16.7mm,achieves the index of integrated.In this paper,two kinds of K-band waveguide-to-microstrip transitions are analyzed and designed.They are all done with the coaxial probe.The experimental results show that both the two transitions, the insert loss is less than 0.06dB.By choosing HEMT and a MMIC, we design a high gain, low noise LNA.The LNA finally designed has the characteristic of low noise figure less than 1.1dB,high gain more than 39dB,gain flatness less than 1 dB. The parallel-coupled microstrip image-reject filter achieves attenuation more than 60dB in the image frequency while the return loss up to 14dB in 19 GHz～21 GHz.In this paper, a single-balance mixer with Scotty diode from the company Skyworks is designed.The paper gives the design process and results of the mixer.Conversion loss of the mixer is less than 8.7 dB.The port isolations are up to 20 dB.Agilent ADS and HFSS are used to design, simulate and optimize the circuits. From the results of the testing, we can find that the circuits satisfies the design demands.更多还原