Enabling metamaterial solutions for antennas in wireless internet service provision (WISP)

在无线互联网服务提供（WISP）中，任何使天线更紧凑、更低姿态或更多功能的努力都会带来一定的挑战，例如增加相互耦合和复杂的天线架构，所有这些都会增加天线占地面积，使设计复杂化，并提出制造挑战。尽管针对这些挑战存在解决方案，但它们实际上可能会增加天线的尺寸、重量、复杂性和成本，而且它们通常采用特设或其他经验设计方法。**另一个挑战是已知的天线罩对辐射参数的影响。这些结构的形状由特定应用参数（如抗风性能和美观性）决定，通常不会用于增强天线性能，尽管它们提供了一个有趣的机会。**上述挑战需要一个更强大的解决方案，利用天线设计的新范例。其中一个范例是电磁（EM）“超材料”（mtm），这是一种周期性结构，用于创造奇异的波传播特性-通常使用天然材料是不可用的-并且可以进一步分为几种类型。其中包括电磁带隙结构（ebg）和某些频率选择表面（fss），前者通常用于定制导波应用中的传播（例如波导和TLs），后者通常用于设计波在自由空间中的传输和反射响应。与KP Performance Inc.（埃德蒙顿，AB -简称KPPA）的拟议合作将研究**设计紧凑型多功能分集天线，该天线将结合基于mtm的EBG**技术的最新进展，以减少互耦，实现宽带和/或多频段操作。这项工作的第二个方面将分别使用基于mtm的fss和EBGs对天线天线罩和地平面进行图图化研究，以实现更好的半功率波束宽度滚降、低侧瓣和改进的前后比。

In wireless internet service provision (WISP), any efforts to render antennas more compact, low-profile, or**multifunctional can bring certain challenges such as increased mutual coupling and complex antenna**architectures, all of which variously enlarge antenna footprints, complicate design, and present fabrication**challenges. Although solutions exist for these challenges, they may actually increase the size, weight,**complexity, and cost of the antenna, and they typically employ ad-hoc or otherwise empirical design methods.**A separate challenge is the known effect of radomes on radiation parameters. These structures, whose shapes**are dictated by application-specific parameters such as wind resistance and aesthetics, are not typically**exploited to enhance antenna properties, although they present an interesting opportunity to do so.**The above challenges demand a more robust solution drawing on new paradigms in antenna design. One such**paradigm is that of electromagnetic (EM) 'metamaterials' (MTMs), which are periodic structures engineered to**create exotic wave-propagation characteristics - often unavailable using natural materials - and which may be**further classified into several types. Among these are EM bandgap structures (EBGs) and certain incarnations**of frequency-selective surfaces (FSSs), where the former are typically used to tailor propagation in**guided-wave applications (e.g. waveguides and TLs) and the latter are typically used to engineer the**transmission and reflection response of waves in free space.**The proposed collaboration with KP Performance Inc. (Edmonton, AB -- abbreviated KPPA) will investigate**designing compact multifunction diversity antennas that incorporate recent advances in MTM-based EBG**technology to enable broadband and/or multi-band operation with reduced mutual coupling. A second aspect of**this work will examine patterning antenna radomes and ground planes using MTM-based FSSs and EBGs,**respectively, to effect better half-power beamwidth roll-off, low side-lobes, and improved front-to-back ratios.