【作者】 彭浩；

【导师】 杨涛；

【作者基本信息】 电子科技大学 ， 电磁场与微波技术， 2013， 博士

【摘要】 近年来随着无线通信技术的飞速发展，无线通信产品越来越普及，已经成为当今人类信息社会发展的重要组成部分。射频接收机位于无线通信系统的最前端，其结构和性能将直接影响整个通信系统。选择优化的设计体系结构和合适的制造工艺，并提高系统的性价比，是研究人员追求的方向。实用的接收机有两种基本的体系结构：超外差式和零中频式（又称直接变频）。超外差结构作为最经典的接收机结构，长期在无线系统中扮演着非常重要的角色。近年来，由于直接变频结构具有构造简单、不存在镜频干扰、可依靠低通滤波器进行低频信道的选择、易于集成等优点，逐渐成为研究的热点。直接变频接收机能完成测相、测频、测向、测距和解调数字信号等诸多功能，具有良好的发展前景和广泛的用途。六端口技术作为直接变频接收机中的关键技术，研究者倾注了大量精力对其进行了深入探索，并取得了相应的进展。本论文将研究基于六端口技术的直接变频接收机，完成理论推导、电路功能模块的设计、系统原理框图组建和实物测试平台的搭建等工作。研究工作包括以下一些内容：宽（窄）带六端口结的设计与实现，基于六端口技术的测相法、测频法、测向法和定位法，高增益放大器的设计与实现，基于人工神经网络（ArtificialNeural Networks, ANN）和支持向量回归（Support Vector Regress，SVR）的校准技术，器件和收发系统LTCC（Low Temperature Co-fired Ceramic）小型化设计等。本文的主要工作包括以下几个方面：1.系统地介绍了六端口技术的理论，六端口反射仪和基于六端口技术的直接变频接收机的工作原理。根据六端口结的工作原理和设计方法，设计制作了窄带六端口结。为了进一步拓展带宽，研究了两种类型的超宽带功分器和3dB耦合器。基于这些器件，构建了两种超宽带的六端口结；2.构建基于六端口技术的测相、测频、测向和定位系统，完成相关的系统搭建工作，并解决了系统自激振荡、串扰、相位漂移等工程难题。高增益射频放大器是直接变频接收机的设计难点之一。电源线串扰、电磁波空间辐射、内部级联放大器的相互影响等因素将引起放大器自激振荡。在设计时，需要仔细考虑这些因素引入的不确定性，并给出相应的解决对策。基于高增益射频放大器设计的接收系统，需从电磁兼容的角度去搭建系统整机，防止信道和模块间的干扰;3.提出了基于ANN和SVR的校准技术。由于六端口接收机固有的缺陷，如：六端口结幅相的非理想特性、二极管平方率检波器的非线性、微波通道的不一致性等，需要一种简单实用的方法对整个系统进行校准。利用相关仪器测量出一组测试数据，然后将测试数据分为两部分，一部分为训练序列，另一部分为验证序列。训练序列用来得到一个反映输入输出关系的“核”，验证序列的目的是考察“核”的预测效果；4.针对宽带六端口结占用面积较大的缺点，设计了基于LTCC工艺的宽带器件，如3dB耦合器和功分器等。微带和波导是能量传输的两种基本方法，微带线和空气波导特性阻抗的巨大差异使两者之间的过渡结构成为研究的难点，作者提出了利用多谐振片和多节阻抗变换的方式来拓展工作带宽。同时，还构建了小型化LTCC的收发系统。更多还原

【Abstract】 With the rapid development of the wireless communication technology, wirelesscommunications products have become a significant part of the developing informationworld. RF receiver, located in the forefront of the wireless communication system,directly determines the structure and performance of the system. Therefore, theresearchers are committed to optimizing the design of the structure and choosing theappropriate manufacturing process in order to improve the performance-to-price ratio.Practical receiver system has two basic architectures: superheterodyne andzero-intermediate frequency (direct conversion). Superheterodyne receiver is the mostclassic receiver structure, which played a significant role in the wireless system for avery long time. In recent years, the direct conversion receiver has gradually become ahotspot for its simple structure, no mirror-frequency interference, low-frequencychannel selection based on the low-pass filter, ease of integration and other advantages.Direct conversion receivers can be used in the phase measurement, frequencymeasurement, direction finding, position sensor or the demodulation of digital signal.As the core technology of the direct conversion receiver, the researchers try their best tomake progress in six-port technology and have gained some achievements these years.In this thesis, the direct conversion receiver based on the six-port technology isdiscussed. The theoretical derivation, design of circuit module, composition of the blockdiagram, structure of test platforms and some related tasks are proposed as well. Themain contents of this thesis are summarized as follows: the design and implementationof the wideband (narroband) six-port junction, some measurement techniques based onthe six-port technique (phase measurement, frequency measurement, direction finding,position sensor), the design and implementation of the high-gain amplifier, thecalibration technique based on the ANN (Artificial Neural Networks) and SVR (SupportVector Regress), the miniaturization of components and system via LTCC (LowTemperature Co-fired Ceramic), etc. This thesis is divided as the following aspects:1. The theory of six-port technology, the principles of six-port reflectometer anddirect conversion receiver based on six-port technology are introduced systemly. Based on the principles and the design methods of the six-port junction, a narrowband six-portjunction is designed and manufactured. To expand the bandwidth, we designed twokinds of ultra-wideband power dividers and3dB couplers to elucidate two types ofultra-wideband six-port junctions.2. Based on the six-port technology, the systems of phase measurement, frequencymeasurement, direction finding and position sensor are intensively studied. Someengineering problems occurring in these systems such as self-oscillation, crosstalk, andphase drift have been solved. One of the difficulties is the design of hign-gain amplifier.The crosstalk of power supply, electromagnetic radiation, interaction of internalcascaded amplifiers and other factors can lead to the self-oscillation. These uncertainfactors need to be taken into considerations, and the corresponding solutions areproposed in the circuit design. The electromagnetic compatibility is utilized in theintegration of receiver system, based on the high-gain RF amplifier.3. The calibration techniques based on ANN and SVR is introduced. Owing to theinherent flaws of the six-port receiver, such as the non-idealitied of amplitude and phasecharacteristics in six-port junction, the nonlinearity of diode detector, theinconsistencies of microwave channel and other factors, the system need to becalibrated by a simple and practical methods. First of all, a set of test data is obtained bythe instrumentation. Then all of the test data is divided into two parts: training andcross-validation data set. The training data set is used to obtain a “kernel function” toreflect the relationship between the input and output, while cross-validation data set isused to verify the predicted effect of “kernel function”.4. The wideband3dB coupler and power divider based on the LTCC technologyare designed to reduce the circuit area of the six-port junction. Microstrip line andair-filled waveguide are two basic energy transmission pathways. However, theenormous difference in the characteristic impedance between them makes impedancematching difficult. To expand the bandwidth Multi-resonant patches andmulti-impedance transformation sections are added into the LTCC dielectric materialand the transmission line, respectively. Furthermore, the LTCC miniaturization of thetransceiver system has been studied in this thesis.更多还原