基于液晶的太赫兹电控扫描传输阵列天线
发布时间：2018-10-24 18:47
【摘要】：太赫兹电控扫描天线能灵活的控制波束方向,提升太赫兹应用系统的时效性和准确性,因此成为了太赫兹天线技术研究的热点问题。目前,太赫兹电控扫描天线通常利用石墨烯和液晶作为电调介质实现波束扫描,然而,受限于制备工艺,当前高纯度的石墨烯难以大面积生产,这限制了石墨烯在太赫兹天线技术中的推广。在液晶电扫反射阵列天线中,由于馈源喇叭的遮挡效应,天线波束的扫描范围也受到了较大影响。为了解决上述问题,本文利用液晶的电调特性,对传输阵列天线进行研究。首先设计了单层液晶移相单元,在340 GHz可以实现90°的移相量。其次,为了增大阵列单元移相量,设计了双层液晶移相单元,单元在340 GHz实现了180°的移相量,且插入损耗始终保持在1 d B左右。最后,利用双层液晶移相单元完成了1-bit数字化液晶电扫传输阵列天线的设计,波束扫描范围达到了-40°~+40°。设计的液晶电扫传输阵列天线为太赫兹频段内电控扫描天线的设计提供了新的思路。此外,本文对液晶的介电特性也进行了深入研究,从液晶材料中射频电场与静电场矢量方向为切入点,提出了一种优化液晶等效介电常数调谐范围的方法:对液晶中射频电场与静电场矢量方向的角度差进行建模,并采用分权相加的思路来调和液晶层中各位置角度差与射频电场的关系,进而判断液晶调谐力度的大小,并通过对比仿真验证了这种优化方法的正确性。这种优化方法对今后液晶调谐器件的设计具有一定的参考价值。
[Abstract]:THz scanning antenna can flexibly control the direction of the beam, improve the timeliness and accuracy of THz application system, so it has become a hot issue in the research of THz antenna technology. At present, terahertz electronic controlled scanning antenna usually uses graphene and liquid crystal as electrically modulated medium to realize beam scanning. However, limited by the preparation process, it is difficult to produce high purity graphene in large area. This limits the spread of graphene in terahertz antenna technology. The scanning range of the antenna beam is also greatly affected by the shielding effect of the feed horn in the liquid crystal electro-sweep array antenna. In order to solve the above problems, the transmission array antenna is studied by using the electromodulation characteristics of liquid crystal. First, a single-layer liquid crystal phase shifting unit is designed, which can realize 90 掳phase shift at 340 GHz. Secondly, in order to increase the phasor of array elements, a double-layer liquid crystal phase-shifting unit is designed. The phase shift of the cell is 180 掳at 340 GHz, and the insertion loss is always about 1 dB. Finally, the design of 1-bit digital LCD transmission array antenna is completed by using double-layer liquid crystal phase shifting unit. The beam scanning range is -40 掳~ 40 掳. The design of liquid crystal electro-sweep transmission array antenna provides a new idea for the design of electronic controlled scanning antenna in terahertz band. In addition, the dielectric properties of liquid crystal are also studied in this paper, starting from the direction of RF electric field and electrostatic field vector in liquid crystal material. A method for optimizing the tuning range of the equivalent dielectric constant of liquid crystal is proposed. The angular difference between the radiofrequency electric field and the vector direction of electrostatic field in liquid crystal is modeled. The relationship between the position angle difference and the RF electric field in the liquid crystal layer is adjusted by using the idea of separation of power and addition, and the magnitude of the tuning force of the liquid crystal is judged, and the correctness of the optimization method is verified by comparison and simulation. This optimization method has certain reference value for the design of liquid crystal tuner in the future.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN820.15
本文编号：2292241
[Abstract]:THz scanning antenna can flexibly control the direction of the beam, improve the timeliness and accuracy of THz application system, so it has become a hot issue in the research of THz antenna technology. At present, terahertz electronic controlled scanning antenna usually uses graphene and liquid crystal as electrically modulated medium to realize beam scanning. However, limited by the preparation process, it is difficult to produce high purity graphene in large area. This limits the spread of graphene in terahertz antenna technology. The scanning range of the antenna beam is also greatly affected by the shielding effect of the feed horn in the liquid crystal electro-sweep array antenna. In order to solve the above problems, the transmission array antenna is studied by using the electromodulation characteristics of liquid crystal. First, a single-layer liquid crystal phase shifting unit is designed, which can realize 90 掳phase shift at 340 GHz. Secondly, in order to increase the phasor of array elements, a double-layer liquid crystal phase-shifting unit is designed. The phase shift of the cell is 180 掳at 340 GHz, and the insertion loss is always about 1 dB. Finally, the design of 1-bit digital LCD transmission array antenna is completed by using double-layer liquid crystal phase shifting unit. The beam scanning range is -40 掳~ 40 掳. The design of liquid crystal electro-sweep transmission array antenna provides a new idea for the design of electronic controlled scanning antenna in terahertz band. In addition, the dielectric properties of liquid crystal are also studied in this paper, starting from the direction of RF electric field and electrostatic field vector in liquid crystal material. A method for optimizing the tuning range of the equivalent dielectric constant of liquid crystal is proposed. The angular difference between the radiofrequency electric field and the vector direction of electrostatic field in liquid crystal is modeled. The relationship between the position angle difference and the RF electric field in the liquid crystal layer is adjusted by using the idea of separation of power and addition, and the magnitude of the tuning force of the liquid crystal is judged, and the correctness of the optimization method is verified by comparison and simulation. This optimization method has certain reference value for the design of liquid crystal tuner in the future.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN820.15
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