C与Ku波段镜像抑制混频器的研究

发布时间：2018-06-05 13:19

本文选题：自激混频器 + C与Ku波段　；参考：《电子科技大学》2016年硕士论文

【摘要】：混频器作为现代无线通信系统中的重要组成部分,其性能的好坏会直接影响整个通信系统的优劣。自100多年前混频器被发明以来,其在当代通信系统中的应用越来越广泛。因此,对混频器的研究具有重要的意义。本文主要依据自激混频器理论,研究并设计了无需外部振荡源的单管自激混频器,并以此为基础,完成了C与Ku波段镜像抑制混频器的设计。本文中的单管自激混频器不仅能够起到混频的作用,还能够自激产生本振信号,从而降低了混频器对外部本振源的依赖。首先,为了使混频器能够自激产生振荡信号,本文根据并联反馈式振荡器的基本原理,采用基片集成波导谐振器作为选频网络,实现了振荡频率为9.9GHz左右的振荡器。然后,本文在振荡器中加入射频输入端口和中频输出端口,并对两个端口的匹配网络进行设计,实现了单管自激混频器。最后,通过在自激混频器的射频输入端接入镜像抑制滤波器,完成了C与Ku波段镜像抑制混频器设计。实物测试结果表明,当漏极直流电压为2.5V,源极直流电压为-0.35V,输入信号频率范围为6.9GHz-8.0GHz时,射频与中频端的隔离度大于26dB,变频增益大于2.1dB,镜像抑制度大于38dB。为了使自激混频器产生的振荡信号性能更好,本文对振荡信号进行了锁相。首先通过在基片集成波导中加载变容二极管,使振荡信号能够在9.92GHz±21MHz的频率范围内电压可控。然后,将这个可调谐的自激混频器与分频器、锁相芯片、环路滤波器联合起来,在ADISimPLL仿真软件中完成锁相电路的仿真。最后,通过稳压芯片为锁相电路提供直流电源,进而完成整个电路的设计。实测结果表明,当输入频率为7GHz-8.4GHz时,变频增益大于2.3d B,相噪为10kHz@-87.7dBc/Hz、100kHz@-107.7dBc/Hz and 1MHz@-113.3dBc/Hz。本文采用了多种仿真软件进行自激混频器、镜像抑制混频器以及锁相电路的设计。经过仿真和优化,采用PCB工艺对其加工,进而得到最终的电路实物。通过测试,其结果与仿真结果是吻合的,从而验证了本文设计方案的可行性,以及理论分析的正确性。
[Abstract]:As an important part of modern wireless communication system, mixer performance will directly affect the quality of the whole communication system. Since the invention of mixer more than 100 years ago, it has been used more and more widely in modern communication systems. Therefore, the study of mixer is of great significance. Based on the theory of self-excited mixer, a single-transistor self-excited mixer without external oscillation source is studied and designed in this paper. Based on this, the design of C and Ku-band mirror rejection mixer is completed. The single-transistor self-excited mixer in this paper can not only play the role of mixing, but also generate local oscillator signal by self-excitation, thus reducing the dependence of mixer on external local oscillator source. Firstly, in order to make the mixer self-excited to generate oscillatory signals, the oscillator with oscillating frequency about 9.9GHz is realized by using the substrate integrated waveguide resonator as the frequency selective network according to the basic principle of the parallel feedback oscillator. Then, the RF input port and if output port are added to the oscillator, and the matching network between the two ports is designed to realize the single-transistor self-excited mixer. Finally, the design of the C and Ku-band mirror rejection mixer is completed by inserting the mirror suppression filter into the RF input of the self-excited mixer. The physical test results show that when the drain voltage is 2.5V, the source DC voltage is -0.35V, and the input signal frequency range is 6.9GHz-8.0GHz, the isolation between RF and if is more than 26dB, the frequency conversion gain is more than 2.1dBand the mirror rejection is more than 38dB. In order to improve the performance of the oscillation signal generated by the self-excited mixer, the phase-locked oscillating signal is carried out in this paper. Firstly, by loading a varactor diode into the substrate integrated waveguide, the oscillation signal can be controlled in the frequency range of 9.92GHz 卤21MHz. Then, the tunable self-excited mixer is combined with the divider, the phase-locked chip and the loop filter to simulate the phase-locked circuit in the ADISimPLL simulation software. Finally, the DC power supply is provided to the phase locked circuit by the voltage stabilizer chip, and the design of the whole circuit is completed. The measured results show that when the input frequency is 7GHz-8.4GHz, the frequency conversion gain is greater than 2.3 dB, and the phase noise is 10kHz @ -87.7dBc / Hz-107.7dBc / Hz and 1MHz Bc / Hz. In this paper, a variety of simulation software is used to design self-excited mixer, mirror rejection mixer and phase-locked circuit. After simulation and optimization, PCB process is used to process it, and the final circuit is obtained. The experimental results are in good agreement with the simulation results, which verifies the feasibility of the design scheme and the correctness of the theoretical analysis.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TN773

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