【作者】 李龙；

【导师】 赵建勋； 闫炳仓；

【作者基本信息】 西安电子科技大学 ， 生物医学工程， 2014， 硕士

【摘要】 在无线电技术领域,对于设备间的信息传输,天线具有着不可替代的重要作用。微带天线作为天线的一种,由于其低剖面、性能多样化、体积小、重量轻、易于集成的特点可以被制成多功能,可共形的天线。近年来随着科技的不断发展,以及对微波频带的广泛利用,人们对微带天线的研究也越来越深入。本文主要研究了一种低功耗的在室内进行短距传输的双V型槽微带天线,工作频率在2.2GHz~2.4GHz,天线辐射方向为对称双向微带天线,并对该微带天线的环境适应性和对人体的辐射做了分析。首先,根据微波电路等效原理以及设计天线性能指标提出了整个天线的设计思路。通过对该天线等效电路的分析计算,初步提出了天线的尺寸规格。并利用XFDTD软件建立了该天线的仿真模型,计算并分析了该天线的增益、效率、方向性系数等性能参数。其次,依据对天线性能参数的分析结果,通过改变开槽结构的办法来改变表面电流的分布特性,以达到提高天线辐射能力的效果。最后,对改进后的天线模型进行模拟仿真,验证了天线经过改进后达到了优化效果。本文进一步对双V型槽微带天线的室内传输进行了仿真模拟。简要分析了两种不同的混凝土结构室内模型的电磁特性。对两种不同的混凝土室内模型建模,分析了双V型槽微带天线在两种混凝土室内环境中的电磁仿真结果。并通过对电磁仿真结果的分析,指出了为了提高室内环境中的传输效率应该采用介电常数为4.3,厚度为1.6mm的介质板。由于双V型槽微带天线的设计工作环境处于室内给排水系统处,所以本文对该微带天线在这种环境下的适应能力也做了初步研究。分析了层间距变化和环境湿度变化对微带天线电磁波传输的影响。通过电磁仿真模拟,讨论了层间距变化对双V型槽微带天线电磁波传输性能的影响,并分析了随着湿度变化所引起的混凝土介电常数变化对双V型槽微带天线电磁波透射率及传输性能的影响。验证了本文所设计的双V型槽微带天线对工作环境能够较好地适应。目前的室内天线设计中我们不仅要考虑到天线的各种传输性能还要考虑到室内天线在长时间工作时所产生的辐射对人体健康的影响。本文主要利用从Zubal人体模型中抽取的数据建立了人体电磁仿真模型。并通过XFDTD的计算得出了人体各个部位在双V型槽微带天线照射时SAR值分布的情况。并通过对人体SAR值情况的研究,分析了天线对人体组织的辐射剂量。说明了本文所设计的天线在室内工作时辐射水平很低,对人体几乎不存在有害的影响。更多还原

【Abstract】 In the field of radio technology, the antenna has been playing an irreplaceable role for the transmissions between different equipments. The microstrip antenna, as one special kind of antennas, has various characteristics including low section, performance diversification, small volume, light weight and ease of integration, thus it can be made into the multi-functional and conformal antennas. In recent years, with the continuous development of science and technology, as well as the wide utilization of the microwave band, the research of the microstrip antenna has been moved towards increasing sophistication. The paper mainly focuses on the research of the microstrip antenna with dual V-shaped slots and low power consumption, which is widely used for the interior short-distance transmissions. Its operating frequency is between 2.2 GHz to 2.4 GHz,with symmetric and bi-directional radiation direction. Furthermore, the paper analyzes and interprets the environmental adaptability and the radiant effects on human bodies of the microstrip antenna.First of all, the whole design idea of the microstrip antenna has been proposed according to the equivalent principle of microwave circuit and the performance requirements of the antenna. The size of the antenna has been determined on the basis of particular analysis and accurate calculation for the antenna equivalent circuit. Then the simulation model has been established with the utilization of XFDTD software,calculating and analyzing various performance parameters including the antenna gain,efficiency, directivity etc. Secondly, the research means to improve the radiation capability of the antenna by changing the structure of the slots and converting the distribution characteristics of the surface current, on the basis of the results for analyzing antenna performance parameters. Finally, the simulation has been applied for the enhanced antenna model, verifying that the optimization for the antenna can be achieved after improvement.The paper further interprets that the simulation for the interior transmission effect of the microstrip antenna with dual V-shaped slots has been conducted, analyzing the magnetic properties of two different indoor models with different concrete structures. Firstly, the two different indoor models have been established for analyzing the simulation magnetic results for the microstrip antenna operating in different indoor environments.Finally, it is noted that the dielectric-slab with the dielectric constant of 4.3 and thickness of 1.6 mm should be used to improve the transmission efficiency of the microstrip antenna with dual V-shaped slots operating in the interior environment.As the designed operating environment for the microstrip antenna with dual V-shaped slots locates in the interior water supply and drainage system, the paper makes a preliminary study for the adaptability of the antenna in the special environment. The writer analyzes the influence for the electromagnetic wave transmission of the microstrip antenna caused by the changing the layer spacing and environmental humidity. Electromagnetic simulation is applied for further discussion of the influence for the antenna caused by the layer spacing change. Also the humidity change can influence the dielectric constant of the concrete, then influencing the transmittivity of electromagnetic wave and the transmission performance for the antenna. Finally, the writer verifies that the design of the microstrip antenna with dual V-shaped slots can adapt to the operating environment and meet the design requirements.It is pointed out that as of the interior antenna design work, we should consider not only the various transmission performance of the antennas, but also their radiant influence on human bodies after long-term operation. The paper indicates that the electromagnetic simulation model of human body has been established by taking advantage of the selection models from Zubal human model system. When the microstrip antenna with dual V-shaped slots operates upon the human bodies, the writer uses XFDTD to calculate the distribution status of SAR value. After careful research of the SAR value status, analysis of the influence to human bodies by the antenna can be obtained. In summary, it is noted that the designed antenna has no harmful influence on human bodies, due to its low radiation in the interior operating environment.更多还原