Metamaterial-based electromagnetic bandgap structures for surface-wave suppression and mutual-coupling reduction in GPS antennas

基于超材料的电磁带隙结构，用于 GPS 天线中的表面波抑制和互耦减少

• 批准号: 441862-2012
• 负责人: Iyer, Ashwin
• 金额: $ 2万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Collaborative Research and Development Grants
• 财政年份: 2013
• 资助国家: 加拿大
• 起止时间: 2013-01-01 至 2014-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=534114
• 关键词: Metamaterial; based; electromagnetic; bandgap; structures

Multipath interference represents a serious problem for high-precision GPS systems. These signals, which are produced by multiple reflections due to low-elevation objects such as buildings and the earth, obscure the interpretation of actual line-of-sight (LOS) GPS data and corrupt the accuracy and speed with which a GPS receiver can detect its location. Multipath signals are often picked up via unwanted surface waves that exist on the metallic groundplanes that back conventional printed antennas. These surface waves are also responsible for the deleterious coupling that occurs between antenna elements in printed-antenna arrays. Electromagnetic bandgap (EBG) structures are periodic surfaces that have proven very successful in suppressing surface waves on groundplanes by presenting to them a bandgap, which forbids propagation. However, conventional EBGs have a periodicity on the order of lambda/2, and several periods are necessary for adequate suppression, much like a filter. As a result, antennas employing EBG structures are often unreasonably large. Metamaterials, which are similar to EBGs but possess extremely small periodicities, may provide a solution to this drawback. The transmission-line (TL) metamaterial, in particular, is inherently suited to integration with printed-circuit technologies and is known for its well-developed design methodology and ease of implementation. This project attempts to characterize, design, fabricate, and test, TL metamaterial-based, miniaturized EBG groundplanes to suppress surface-wave excitation, while simultaneously attempting to optimize GPS-antenna parameters such as radiation pattern, axial ratio (AR) bandwidth, efficiency, and capacity for multi-band operation. This will be a collaborative effort between the research group of Prof. Ashwin K. Iyer (University of Alberta, Edmonton, AB) and GPS-antenna manufacturer NovAtel Inc. (Calgary, AB).

多径干扰是高精度GPS系统面临的一个严重问题。这些信号是由诸如建筑物和地球之类的低海拔物体的多次反射产生的，它们模糊了对实际视线（LOS）GPS数据的解释，并破坏了GPS接收机检测其位置的精度和速度。多径信号通常通过存在于支撑传统印刷天线的金属接地层上的不需要的表面波拾取。这些表面波也是印刷天线阵列中天线元件之间发生有害耦合的原因。电磁带隙（EBG）结构是周期性表面，其已被证明通过向接地层呈现禁止传播的带隙而在抑制接地层上的表面波方面非常成功。然而，常规EBG具有λ/2量级的周期性，并且几个周期对于足够的抑制是必要的，很像滤波器。因此，采用EBG结构的天线通常过大。类似于EBG但具有极小周期性的超材料可以提供该缺点的解决方案。特别是传输线（TL）超材料，天生适合与印刷电路技术集成，并以其成熟的设计方法和易于实现而闻名。该项目试图表征、设计、制造和测试基于TL超材料的小型化EBG接地层，以抑制表面波激励，同时试图优化GPS天线参数，如辐射方向图、轴比（AR）带宽、效率和多频带操作容量。这将是Ashwin K. Iyer（阿尔伯塔大学，埃德蒙顿，AB）和GPS天线制造商NovAtel Inc.（卡尔加里，AB）。