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In this article chapter, we discuss different ways to mitigate some of the problems encountered with MTMs, and present strategies for artificially synthesizing dielectric materials that are broadband as well as low-loss; hence, they are useful for real-world antenna applications involving low-profile flat lenses and reflectarrays, for example. The key to circumventing the difficulties with MTM, which we have identified above, is to steer clear of the common practice of using resonant inclusions or “particles”to achieve extreme material properties, negative index; and, zero index. Our strategy is to develop antenna designs that only call for material parameters that are realistic, so that they can either be acquired off-the-shelf, or by slightly tweaking the available materials by embedding small patches or apertures, often referred to as “particles”, whose dimensions are far removed from the resonance range. This obviates the problems of dispersion, narrow bandwidths and losses that plague the MTMs, at least those that fall in the “exotic”category, for example, the doublenegative or DNG type. Although the RO approach leads to dielectric-only designs that do not need to use magnetic materials, these designs still typically require dielectric materials that may not be available off-the-shelf. |
