Novel electromagnetic properties of engineered metamaterials provide new directions in RF design. Among these, extraordinary band structures of electromagnetic band gap (EBG) materials and negative index metamaterials (NIM) have already been successfully employed to realize high impedance ground planes, sub-wavelength focusing, smaller RF devices, and miniature antennas [1–3]. Alternatively to NIMs, mode diversity and higher order dispersion (K-ω) curves of periodically layered anisotropic materials have recently been proposed for miniature antenna applications. These anisotropic material arrangements split the conventional K-ω curves into two branches as depicted in Fig. 1(a). Mode coupling between the branches (via misaligned anisotropy) creates novel slow group velocity modes associated with higher order band edge behaviors. When such dispersion relations are realized on traditional microwave substrates (via printed coupled line emulations in Fig. 1(b)), they offer additional design flexibilities to enable antenna miniaturization, bandwidth, and gain enhancement [4–5].
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