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

在无线互联网服务提供(WISP)中，任何试图使天线更紧凑、更低调或更多功能的努力都会带来一定的挑战，例如增加互耦合和复杂的天线结构，所有这些都会不同程度地扩大天线占地面积，使设计复杂化，并带来制造挑战。虽然已经有了解决这些挑战的方案，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别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的应用参数决定，例如风阻和美观，虽然它们提供了一个有趣的机会来增强天线的性能，但并没有被典型地利用来增强天线的性能。上述挑战需要一个更强大的解决方案，利用新的天线设计范例。其中一种模式是电磁(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获得--并可进一步分为几种类型。其中包括电磁带隙结构(EBG)和某些实现的频率选择表面(FSS)，其中前者通常用于定制传播导频波应用(例如，波导和TL)，而后者通常用于设计波在自由空间中的传输和反射响应。拟议中的与KP Performance Inc.(Edmonton，AB-缩写KPPA)的合作将研究设计紧凑型多功能分集天线，该天线融合了基于MTM的EBG技术的最新进展，以实现宽带和/或多频带操作，减少相互耦合。这项工作的第二个方面将分别使用基于MTM的FSS和EBG来检查天线天线罩和接地面的图案化，以实现更好的半功率波束宽度滚降、低旁瓣和改善的前后比。

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.