【作者】 张慧；

【导师】 洪伟；

【作者基本信息】 东南大学 ， 电磁场与微波技术， 2016， 博士

【摘要】 微波毫米波成像技术是利用微波毫米波接收机来接收背景物体的辐射分布差异特性并形成图像的技术。微波毫米波成像技术在机场安检、飞机着陆导航、军事侦察、医疗诊断等领域有着重要的应用价值,尤其在针对隐匿武器检查的人员安检场合,微波毫米波成像技术有着天然的优势。随着微波毫米波成像场景对成像质量与成像速率要求的不断提高,传统的单通道机械扫描式微波辐射计成像系统越来越无法满足应用需求。随着半导体工艺的发展,微波毫米波器件取得了显著的进步,微波毫米波成像系统取得了突破性进展,在系统尺寸、成像速度、空间分辨率等各方面得到了明显的改善。各种体制的微波毫米波成像系统也不断的得以研究与发展。本论文主要研究基于相控阵体制和数字多波束体制的微波毫米波成像系统,首先研究了适用于相控阵成像系统的移相体制对系统及成像的影响,进而研究了数字多波束毫米波成像系统中的波束成形技术,研究和提出了相控阵成像和数字多波束成像系统设计和实现的几种关键技术。在此基础上,分别设计了Ku频段的被动微波相控阵成像系统和E波段的主动被动毫米波数字多波束成像系统并给出和分析了成像效果。论文的主要工作包括：第一章主要阐述微波毫米波成像的基本原理,重点研究阵列成像尤其是相控阵微波毫米波成像和数字多波束成像的基本原理。从物体辐射的基本原理出发,分析了最基本的实孔径微波辐射计及测量场景亮温的工作原理,并给出了相控阵体制的微波毫米波成像系统结构,进而给出了数字多波束体制的毫米波成像系统结构,并分析了其进行成像测量的工作原理。第二章研究了一种基于直接数字频率合成的移相方案并将其改进后引入到相控阵微波成像中,方案克服了数字移相器方案的波束移相稀疏特性,使得成像波束能够以极低的间隔进行扫描,从而有效提高了成像分辨率与成像质量,显著减少了后端数字图像处理的工作量。第三章提出并实现了一种基于基片集成波导(SIW)的平面电路互连方法,该方法使用SIW作为模块端口侧传输线,利用SIW传输的特点,引入双层金属结构导流与屏蔽,无需任何焊接与额外接头,即可实现非常优异的传输性能。该方法主要是为了解决毫米波电路设计中电路或模块之间的互连与移植问题,显著降低成本并提高毫米波电路与系统的性能。第四章提出并实现了一种基于SIW的毫米波芯片新型引线键合技术。相比微带引线键合技术,提出的新型引线键合技术可以有效降低对引线键合操作和电路板制作等加工误差的灵敏度,从而有效改善引线键合性能及电路性能。该方法成功地应用在E波段的毫米波成像系统中,有效提高了键合成功率与键合性能。第五章研究并实现了一种基于相控阵体制的Ku频段被动微波成像系统。该系统包含了均匀分布平面阵列的256个天线单元,每个天线单元与一个完整的射频接收单元相连接,使用了基于DDS移相网络的等效移相方案,与传统的机械扫描式的成像方案相比,极大提高了成像速度；与传统的使用移相器的相控阵成像方案相比,大大缩短了扫描步进,实现了对波束的精准扫描,有效改善了成像分辨率。第六章研究并实现了一种基于数字多波束体制的E波段毫米波成像系统。该系统包含了均匀分布平面阵列的16个天线单元,每个天线单元与一个完整的射频接收单元相连接,每个射频接收单元后都有一个完整的中频处理与模数转换器。在该毫米波成像系统中,通过引入基于基片集成波导的电路互连技术和基于基片集成波导的毫米波芯片引线键合技术,有效简化了毫米波频段上电路模块的测试与移植复杂度,提高了毫米波芯片的引线键合性能,降低了毫米波电路的设计与测试难度,改善了毫米波电路的性能与设计成功率。研究成果中有些已在IEEE MWCL,电波科学学报等国内外核心刊物上发表,有些已在IEEE APCAP, IEEE APMC等国际会议上发表或录用,部分工作也申请了专利。更多还原

【Abstract】 Microwave and millimeter wave imaging technologies utilize the microwave and millimeter wave receivers to receive and detect the differences of the background radiation distribution characteristics and then form an image. Microwave and millimeter wave imaging technologies have important values on many fields such as airport security, flight landing navigation, military surveillance, and medical diagnostics. Especially for concealed weapons inspection personnel security situation, microwave and millimeter wave imaging technology has a natural advantage. With the demands for the image quality and imaging speed are continuously increasing, the traditional single-channel imaging system with mechanical scanning technology is unable to meet the demands, and with the development of the semiconductor technology, microwave and millimeter wave devices have made significant progress, the imaging systems acquired a significant improvement on system size, imaging speed, spatial resolution and etc. Varieties of microwave and millimeter wave imaging systems are continuously researched and developed. However, due to the limitations of imaging schemes and the cost, size and performance of the devices, microwave and millimeter wave imaging technology currently still has a huge space for development.This dissertation focused on the microwave and millimeter wave imaging systems based on the phased array schemes and digital multi-beam schemes. Firstly, to study the phase shifting scheme for the imaging system and its effect to the system and imaging results, and then to study the digital multi-beam millimeter wave imaging technology. During these researches, several novel key technologies are proposed and investigated for the microwave and millimeter wave imaging systems, and then a Ku band passive microwave phased array imaging system and a E-band multi-beam imaging system are designed and implemented, and the relevant results of design and imaging are displayed and analyzed. It is organized as follows:Chapter 1 makes an introduction to the basic principles of the microwave and millimeter wave imaging, especially focusing on the principles of the phased array imaging and digital multi-beam imaging. Based on the basic principles of the object radiation, the principles of the real aperture microwave radiometers and the brightness temperature measurement are analyzed, and the system architectures of the phased array imaging system and digital multi-beam imaging system are indicated and analyzed.Chapter 2 studied and implemented a phase shifter scheme based on direct digital synthesis (DDS) designed for phased array microwave and millimeter wave imaging system, which can overcome the sparse phase shifting features of digital phase shifter scheme and the imaging beam can be scanned with very fine intervals, thus effectively improving the imaging resolution and quality, significantly reducing the workload the digital imaging processing.Chapter 3 proposed and implemented a planar circuits interconnection based on substrate integrated waveguide (SIW), which using SIW as the transmission line of a module port to realize an excellent transmission performance by introduction a double-layer metal structure for shielding and current diversion without any additional welding or connectors. This method is proposed and designed to solve the flexible interconnections issues between millimeter wave circuits and modules, which can significantly improve the performance of millimeter wave circuits and systems, improve the flexibility of the circuit design and migration, reduce the design and implementation costs.Chapter 4 proposed and implemented a novel wire bonding technology directly based on SIW. Compared to traditional microstrip wire bonding, the proposed SIW bonding technology can effectively reduce the sensitivity to bonding operations and circuit production accuracy, and then significantly improve the wire bonding performance. This method has been successfully applied in the E-band millimeter wave imaging system, effectively improve the success rate and performance of the wire bonding operation.Chapter 5 studied and implemented a passive Ku-band phased array microwave imaging system. The imaging system comprises an antenna array containing 256 antenna elements uniformly distributed in two dimensional surface, each antenna is followed by a complete RF receiver, compared to the traditional mechanical scanning radiometers, by using the equivalent LO phase shifter based on DDS, the imaging system greatly reduces the scan intervals, achieves a very fine beam scanning and effectively improves the imaging quality.Chapter 6 studied and implemented a multi-beam E-band millimeter wave imaging system. The imaging system comprises an antenna array containing 16 antenna elements uniformly distributed in two dimensional surface. Each antenna is followed by a complete RF receiver, and each RF receiver is followed by complete IF circuit and ADC circuit. In this system, by introducing the circuits interconnection technology based on SIW and the wire bonding technology based on SIW technology, the testing and migration complexity in the millimeter wave band are effectively simplified, the wire bonding performance of the millimeter wave chips are improved, the difficulty of the millimeter wave circuit design and test are reduced, and the millimeter wave performance and success rate of design are increased.Part of this work has been published in the journal of IEEE Microwave and Wireless Components Letters, vol.24, Issue 11,2014, some international conferences. Several patents have also been filed.更多还原