基于梯度折射率器件的波束扫描阵列研究

发布时间：2018-03-31 05:26

本文选题：梯度折射率器件　切入点：波束扫描阵列　出处：《中国科学技术大学》2016年博士论文

【摘要】：波束扫描阵列可以实现电磁波的高增益辐射和扫描,但在应用时存在扫描范围有限,系统复杂的问题。梯度折射率器件可以实现电磁波传播方向的调控,将其应用于波束扫描,具有传统波束扫描阵列所不具备的优势。变换光学和超材料(Metamaterial)分别从理论和实现方法上为设计新型梯度折射率器件提供了有力工具。如何设计具有波束扫描潜力的新型梯度折射率器件,进而实现扫描范围广、结构简单的波束扫描阵列,是目前电磁场和微波毫米波领域研究的热点。本文首先研究了基于球梯度龙伯透镜的波束扫描阵列。根据球梯度龙伯透镜可将沿任意方向入射的平面波聚焦于其表面一点的特性,将离散天线单元均匀排布于龙伯透镜表面,通过对离散天线单元顺序馈电实现了宽扫描范围内的高增益波束扫描；在此基础上,提出利用天线阵列对球梯度龙伯透镜进行馈电,通过控制每个阵元的馈电幅度和相位分布,实现对阵列相位中心的调整,进而实现一定角度范围内的等增益连续波束扫描；设计加工了1×4单极子天线阵列和满足三种扫描角度的幅相馈电网络,对龙伯透镜波束扫描阵列的高增益、小角度扫描范围内等增益连续扫描特性进行了实验验证。其次,研究了基于平面化龙伯透镜的波束扫描阵列。分析了现有的平面化龙伯透镜的焦平面尺寸与可容纳平面天线单元数目的关系,指出现有方法设计的平面化龙伯透镜焦平面尺寸有限,难以容纳足够数目的平面阵元以实现扫描范围内半功率波束全覆盖的缺点；基于变换光学原理提出了平面化龙伯透镜焦平面的延展设计方法,该延展焦平面可容纳足够数目的平面阵元,进而实现扫描范围内半功率波束的全覆盖；设计并加工了具有延展焦平面的平面化龙伯透镜,在其焦平面处对1×9的微带阵列进行顺序馈电,实现了±42°扫描范围内半功率波束的全覆盖。最后,基于光学双折射原理,提出了基于介质周期结构的非磁性双折射梯度折射率透镜。分析了不同类型梯度折射率器件实现双折射所需满足的介电常数分布；然后基于龙伯透镜对平面波的聚焦特性和伊顿透镜对平面波的偏转特性,研究了对入射平面波的垂直和水平极化分量分别具有聚焦和偏转功能的双折射径向梯度折射率介质透镜；在此基础上,设计了一款对垂直极化波聚焦、对水平极化波偏转角度为30°的双折射介质透镜,并对其进行了验证。
[Abstract]:Beam scanning array can realize the high gain radiation and scanning of electromagnetic wave, but the scanning range is limited and the system is complex. The gradient refractive index device can adjust the direction of electromagnetic wave propagation and apply it to beam scanning. The transformational optics and metamaterialhas provided a powerful tool for the design of new graded refractive index devices in theory and implementation. How to design a new type of graded refractive index device with beam scanning potential? A new type of gradient refractive index device, Then the beam scanning array with wide scanning range and simple structure can be realized. It is a hot topic in the field of electromagnetic field and microwave millimeter wave. Firstly, the beam scanning array based on spherical gradient Lens is studied in this paper. According to the spherical gradient Lens, plane waves incident in any direction can be focused on it. A little bit of surface property, The discrete antenna elements are arranged uniformly on the surface of the Lumber-lens, and the high-gain beam scanning in the wide scanning range is realized by feeding the discrete antenna elements sequentially. On this basis, the antenna array is used to feed the spherical gradient Lens. By controlling the distribution of the feed amplitude and phase of each array element, the phase center of the array can be adjusted, and the constant gain continuous beam scanning in a certain angle range can be realized. The 1 脳 4 monopole antenna array and the amplitude-phase feed network with three scanning angles are designed and fabricated. The high gain and equal gain continuous scanning characteristics of the Longber lens beam scanning array in small angle range are experimentally verified. The beam scanning array based on plane Lumber lens is studied. The relationship between the focal plane size and the number of antenna elements of planar Lens is analyzed. It is pointed out that the focal plane size of the planarized Lombo lens is limited and it is difficult to accommodate enough planar elements to achieve full coverage of half-power beam in scanning range. Based on the principle of transform optics, an extension design method for planar Lombo lens focal plane is proposed. The extended focal plane can accommodate a sufficient number of planar array elements, and then realize the full coverage of half-power beam in scanning range. A planar Lomber lens with extended focal plane is designed and fabricated. The 1 脳 9 microstrip array is fed sequentially at the focal plane. The full coverage of the half-power beam in 卤42 掳scanning range is realized. Finally, based on the principle of optical birefringence, A nonmagnetic birefringent gradient refractive index lens based on dielectric periodic structure is proposed and the dielectric constant distribution required for the realization of birefringence by different types of graded refractive index devices is analyzed. Then, based on the focusing characteristics of the Lomber lens to the plane wave and the deflection characteristic of the Eaton lens to the plane wave, A birefringent radial gradient index dielectric lens with focusing and deflection functions for the vertical and horizontal polarization components of the incident plane wave is studied. The birefringent dielectric lens with 30 掳horizontal polarization wave deflection angle is verified.
【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TN820

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