无线体域网（WBAN）中超宽带及可穿戴天线的研究

发布时间：2018-05-01 20:37

本文选题：超宽带天线 + 可穿戴天线　；参考：《兰州大学》2016年博士论文

【摘要】：无线体域网是以人体为中心的无线网络,在军事和医疗等方面有着广泛的应用前景。超宽带技术由于可以与现有的频谱资源共享频带而得到了广泛的应用,是实现无线体域网的最佳候选技术之一,而其中超宽带天线的设计也对传统的天线设计理论提出了新的挑战。在人体身上佩戴可穿戴天线进行无线数据传输,更能满足无线体域网的需要。本文主要研究用于无线体域网的超宽带天线和可穿戴天线,结合等效电路、传输函数和时域波形来分析超宽带天线的性能;在可穿戴天线中加载电磁带隙结构以减小天线对人体的电磁辐射,研究可穿戴天线在弯折和靠近人体时的特性。本文的主要研究内容和成果如下:1.研究并设计了三款超宽带天线根据电流分布对称切割和缩比原理,得到一种小型化的圆形缝隙超宽带天线,天线的体积缩小到原结构的0.125倍。实测的天线系统传输函数,其幅度在5.5-10.6GHz频率范围内比较平坦,相位近似线性,天线在xz平面内的波形保真度大于0.9750,有利于脉冲信号的传输。根据微波传输线理论,对一种基于半波长开路谐振器的单阻带超宽带天线进行分析,提出了一种基于四分之一波长短路谐振器的单阻带超宽带天线。天线在保持辐射特性几乎不变的情况下,提高了阻带内的电压驻波比值,减小了阻带内的增益值,该天线具有更好的滤波效果。通过在辐射单元和地面上开槽的方法,提出了一种双阻带U形单极子超宽带天线。根据表面电流的分布,在传输线理论分析中分别以并联终端开路传输线和串联终端短路传输线来分析3.5GHz和5.5GHz的阻带特性。由RLC谐振网络组成的等效电路与天线输入阻抗得到的结果一致,验证了等效电路的正确性。2.研究并设计了两款电磁带隙结构在分析矩形贴片电磁带隙结构的基础上,通过金属层内部挖孔的方法实现了小型化,得到一种矩形环状单频电磁带隙结构,该结构具有制作方便的特点,适合可穿戴应用场合。在此基础上又设计了一种矩形环状双频电磁带隙结构,通过选择合理的参数可以实现各自频段的参数调节,同时对另一个工作频段的性能影响很小。通过分析表面电流分布和反射相位曲线,对这两种电磁带隙结构的参数做了优化,用悬置微带线法测量的结果也满足设计要求。3.研究并设计了两款可穿戴天线在分析超宽带圆形缝隙天线的基础上,提出了一种用于2.4GHz WLAN频段的可穿戴圆形缝隙天线,为了减小天线对人体的电磁辐射,在天线结构中加载矩形环状单频电磁带隙结构后,计算的SAR值减小到1g标准的0.554W/kg和10g标准的0.23W/kg,满足美国和欧洲所用的标准。可穿戴圆形缝隙天线的优点是其具有较宽的带宽,在天线弯折时比较容易覆盖所需要的频带;其缺点是谐振频率随着天线的弯折会移动,稳定性较差。提出了一种用于2.4GHz/5.8GHz WLAN双频段的可穿戴平面倒F形天线,天线的两个工作频段可通过调节两个谐振单元的长度实现,而彼此之间影响很小。加载电磁带隙结构后,天线的方向图出现了单向辐射特性;工作频段内天线的增益有所增加;天线对人体的电磁辐射也满足要求。可穿戴双频平面倒F形天线的优点是其具有很好的稳定性,天线弯折对谐振频率的影响很小;其缺点是带宽较窄。本文设计的超宽带天线具有平面化、小型化的特点,易于和微波系统集成;可穿戴天线对人体的电磁辐射满足要求,具有柔韧、舒适的特点,易于集成在衣物中。本文的工作对无线体域网中天线的实用化具有重要的意义。
[Abstract]:Wireless body area network (WSN) is a wireless network based on human body. It has a wide application prospect in military and medical fields. UWB technology is widely used because it can share frequency band with existing spectrum resources. It is one of the best candidate technologies to realize WSN, and the design of UWB antenna is also traditional. The antenna design theory puts forward a new challenge. Wearing wearable antenna for wireless data transmission on human body can meet the needs of wireless body domain network. This paper mainly studies UWB antenna and wearable antenna used in WSN, and combines the equivalent circuit, transmission function and time domain waveform to analyze the performance of UWB antennas. In the wearable antenna, the electromagnetic band gap structure is loaded to reduce the electromagnetic radiation of the antenna to the human body and to study the characteristics of the wearable antenna when it is bent and near the human body. The main research contents and achievements of this paper are as follows: 1. three types of ultra wideband antennas are designed according to the principle of symmetrical cutting and contraction of current distribution, and a miniaturized circle is obtained. The size of the antenna is reduced to 0.125 times that of the original structure. The measured antenna system transmission function is relatively flat in the 5.5-10.6GHz frequency range, the phase is approximately linear. The waveform fidelity of the antenna in the XZ plane is greater than 0.9750, which is beneficial to the transmission of the pulse signal. A single band UWB antenna with a half wavelength open resonator is analyzed. A single band ultra wideband antenna based on 1/4 wavelength short-circuit resonator is proposed. The antenna increases the voltage standing wave ratio in the stopband and reduces the gain in the stopband. The antenna has better filtering. A double band U shaped monopole ultra wideband antenna is proposed by the method of slotting on the radiation unit and the ground. According to the distribution of the surface current, the resistance band characteristics of 3.5GHz and 5.5GHz are analyzed by parallel terminal open transmission line and series Terminal Short-Circuit transmission line in the theoretical analysis of transmission lines. It is composed of RLC resonant network. The equivalent circuit is in agreement with the results obtained by the input impedance of the antenna. The validity of the equivalent circuit is verified by.2. research and the design of two electromagnetic band gap structures is designed on the basis of the analysis of the electromagnetic band gap structure of the rectangular patch, and a rectangular ring single frequency electromagnetic band gap structure has been obtained by digging holes in the metal layer. It has the characteristics of convenient fabrication and suitable for wearable applications. On this basis, a rectangular ring double frequency electromagnetic band gap structure is designed. By selecting reasonable parameters, the parameters of each frequency band can be adjusted, and the performance of the other frequency band is very small. Through the analysis of the surface current distribution and the reflection phase curve, The parameters of the two electromagnetic band gap structures are optimized. The result of the suspension microstrip method is also satisfied with the design requirements.3.. On the basis of the analysis of the ultra wideband circular slot antenna, a wearable circular slot antenna used in the 2.4GHz WLAN band is proposed to reduce the antenna to the human body. Electromagnetic radiation, after loading a rectangular annular single frequency band gap structure in the antenna structure, the calculated SAR value is reduced to the standard 0.554W/kg and 10g standard 0.23W/kg of the 1g standard to meet the standards used in the United States and Europe. The advantage of the wearable circular slot antenna is that it has a wider bandwidth and is easier to cover the required frequency when the antenna is bent. The defect is that the resonant frequency is moved with the antenna's bending and the stability is poor. A wearable planar inverted F antenna for 2.4GHz/5.8GHz WLAN double band is proposed. The two working bands of the antenna can be realized by adjusting the length of the two resonant units, and the influence of each other is very small. After loading the electromagnetic band gap structure, the antenna is square. There is a unidirectional radiation characteristic to the graph; the gain of the antenna in the working band increases; the antenna is also satisfied with the electromagnetic radiation of the human body. The advantage of the wearable double frequency planar inverted F antenna is that it has good stability, the antenna bending has little influence on the resonant frequency; its lack point is the narrow bandwidth. The ultra wideband antenna designed in this paper is designed. It has the characteristics of flatness and miniaturization, which is easy to integrate with the microwave system. The wearable antenna meets the requirements of the electromagnetic radiation of the human body, has the characteristics of flexibility and comfort, and is easy to integrate in the clothing. This work is of great significance to the practicality of the antenna in the wireless body area network.

【学位授予单位】：兰州大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TN822.8

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