模拟宽带幅相均衡器的研究

发布时间：2018-11-25 17:10

【摘要】：射频通信系统中,源于射频器件自身存在的频率选择性以及多级元器件级联等造成系统不理想的幅相特性,主要表现为幅频特性的不平坦和群时延波动,使得传输信号发生畸变,影响系统的通信质量和传输速度。在发射机前端添加模拟宽带幅度均衡器或相位均衡器,是一种最直接且行之有效的改善方法[1],由于体积、功耗、复杂度等的考虑,适合高速率通信的模拟无源均衡器引起研究者们的关注。模拟无源均衡器的均衡量从几dB发展到十几dB,均衡带宽也从MHz发展到GHz[2],但是结构简单、调试方便、低功耗、小尺寸、超宽带以及适用于高频段的均衡器仍有待进一步的探讨和研究。本论文主要研究对象为模拟无源宽带幅度均衡器和相位均衡器。以传统集总元件均衡器为基础,采用电阻加载微带谐振枝节和悬置带线等效替换集总元件两种设计思路来实现结构简单、小尺寸、超宽带的幅度均衡器;相位均衡器方面,从X型全通网络出发,分析其相频特性和群时延关系,推导出几种实用的T型均衡网络,实现宽带相位均衡器。根据不同的均衡频段与均衡目标,分别使用了集总参数结构、微带结构和悬置带线结构三种设计方法,最终设计了五款不同类型的幅度均衡器和三款不同类型的相位均衡器,其主要内容如下:1)介绍了均衡器的研究背景和国内外发展现状等,论述了均衡器在通信系统中的重要性和必要性。2)研究了射频器件的幅相特性及其对系统性能的影响;介绍了均衡器的网络分析方法;同时,简要概述了集总参数网络、微带传输线理论和悬置带线理论,分析了微带线谐振枝节的基本特性和等效电路,研究了悬置带线等效电容、电感的原理和方法。3)模拟宽带幅相均衡器的设计。首先,从RC并联网络和LC谐振枝节出发,引出多种常用集总参数均衡器;以微带传输线和悬置带线等效集总参数电路为基础,分别用微带枝节替换LC谐振枝和悬置带线等效集总元件,推导出微带结构均衡器和悬置带线均衡器;其次,根据均衡器网络分析方法,求解各均衡结构的传输函数,研究均衡器工作带宽、均衡量、时延波动等的影响因子;然后,用ADS和HFSS搭建均衡器仿真电路以及三维电磁结构仿真模型,仿真电路特性并进行调试与优化;最后,用CADENCE绘制均衡器电原理图并印制电路板,以及生产加工后对PCB实物电路进行焊接、调试、测试以及结果分析。
[Abstract]:In the radio frequency communication system, the frequency selectivity and the cascade of multistage components caused the unsatisfactory amplitude-phase characteristics of the radio frequency communication system, which mainly show the uneven amplitude and frequency characteristics and the group delay fluctuation. The distortion of the transmission signal affects the communication quality and transmission speed of the system. Adding analog wideband amplitude equalizer or phase equalizer to the front end of transmitter is the most direct and effective improvement method [1] because of the consideration of volume, power consumption, complexity, etc. Analog passive equalizer for high-rate communication has attracted researchers' attention. The equalizer of analog passive equalizer develops from a few dB to a dozen dB, equalization bandwidth from MHz to GHz [2], but the structure is simple, the debugging is convenient, the power consumption is low, and the size is small. UWB and equalizer for high frequency band still need to be further discussed and studied. The main research objects of this thesis are analog passive wideband amplitude equalizer and phase equalizer. Based on the traditional lumped element equalizer, the amplitude equalizer with simple structure, small size and ultra-wideband is realized by using two design ideas: resistive loaded microstrip resonant branch and equivalent replacement lumped element. In the aspect of phase equalizer, based on X-type all-pass network, the relationship between phase frequency characteristic and group delay is analyzed, and several practical T-type equalizer networks are deduced to realize wide-band phase equalizer. According to different equalization frequency bands and equalization targets, three design methods, lumped parameter structure, microstrip structure and suspended strip line structure, are used respectively. Finally, five different types of amplitude equalizers and three different types of phase equalizers are designed. The main contents are as follows: 1) the research background and development status of equalizer at home and abroad are introduced, and the importance and necessity of equalizer in communication system are discussed. 2) the amplitude-phase characteristic of RF device and its influence on system performance are studied. The network analysis method of equalizer is introduced. At the same time, the lumped parameter network, microstrip transmission line theory and mount strip line theory are briefly summarized. The basic characteristics and equivalent circuit of the resonant section of the microstrip line are analyzed, and the equivalent capacitance of the suspended strip line is studied. Principle and method of inductance. 3) Design of analog wideband amplitude and phase equalizer. Firstly, based on the RC parallel network and the LC resonance branch, many common lumped parameter equalizers are introduced. Based on the equivalent lumped circuit of microstrip transmission line and mount strip line, the LC resonance branch and the mount strip line equivalent lumped element are replaced by the microstrip branch, respectively, and the microstrip structure equalizer and the mount strip line equalizer are derived. Secondly, according to the equalizer network analysis method, the transmission function of each equalization structure is solved, and the influence factors of the equalizer working bandwidth, equalizer, delay fluctuation and so on are studied. Then, the simulation circuit of equalizer and the simulation model of three-dimensional electromagnetic structure are built with ADS and HFSS, and the characteristics of simulation circuit are debugged and optimized. Finally, the electric schematic diagram of equalizer and printed circuit board are drawn with CADENCE, and the PCB physical circuit is welded, debugged, tested and analyzed after production and processing.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN715

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