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、低轮廓或多功能的努力都可能带来某些挑战，例如增加的互耦合和复杂的天线架构，所有这些都不同程度地增大了天线占用空间，使设计复杂化，并提出了制造挑战。尽管存在针对这些挑战的解决方案，但它们实际上可能增加天线的尺寸、重量、复杂性和成本，并且它们通常采用ad-hoc或其他经验设计方法。另一个挑战是天线罩对辐射参数的已知影响。这些结构的形状取决于特定应用的参数，如抗风性和美观性，通常不会被用于增强天线性能，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，借鉴天线设计的新范例。一个这样的范例是电磁（EM）“超材料”（MTM），这是一种周期性结构，旨在创造奇异的波传播特性-通常使用天然材料无法实现-并且可以进一步分为几种类型。其中包括EM带隙结构（EBG）和频率选择表面（FSS）的某些化身，前者通常用于定制传播引导波应用（例如波导和TL），后者通常用于设计波在自由空间中的传输和反射响应。（埃德蒙顿，AB -缩写KPPA）将研究设计紧凑型多功能分集天线，该天线结合了基于MTM的EBG技术的最新进展，以实现宽带和/或多频带操作，同时降低互耦。本工作的第二个方面将分别使用基于MTM的FSS和EBG来研究天线罩和接地层的图案化，以实现更好的半功率波束宽度滚降、低旁瓣和改进的前后比。

In wireless internet service provision (WISP), any efforts to render antennas more compact, low-profile, ormultifunctional can bring certain challenges such as increased mutual coupling and complex antennaarchitectures, all of which variously enlarge antenna footprints, complicate design, and present fabricationchallenges. 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 shapesare dictated by application-specific parameters such as wind resistance and aesthetics, are not typicallyexploited 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 suchparadigm is that of electromagnetic (EM) 'metamaterials' (MTMs), which are periodic structures engineered tocreate exotic wave-propagation characteristics - often unavailable using natural materials - and which may befurther classified into several types. Among these are EM bandgap structures (EBGs) and certain incarnationsof frequency-selective surfaces (FSSs), where the former are typically used to tailor propagation inguided-wave applications (e.g. waveguides and TLs) and the latter are typically used to engineer thetransmission and reflection response of waves in free space.The proposed collaboration with KP Performance Inc. (Edmonton, AB -- abbreviated KPPA) will investigatedesigning compact multifunction diversity antennas that incorporate recent advances in MTM-based EBGtechnology to enable broadband and/or multi-band operation with reduced mutual coupling. A second aspect ofthis 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.