Extraordinary properties found in engineered metamaterials have drawn great interest as they can address industry demands for small, light-weight, and multifunctional devices. It is not therefore surprising that a variety of artificial materials are being widely considered for various radio frequency (RF) applications. Among these metamaterials, a recently introduced class of anisotropic photonic crystals, namely magnetic photonic (MPC) and degenerate band edge (DBE) crystals, has been shown to exhibit unique propagation modes as compared to regular periodic assemblies. For the first time, this dissertation carries out computational and experimental analysis of these new crystals for specific RF applications. Our ultimate goal is to develop high gain antenna apertures and miniature footprint antennas. In this context, this dissertation begins by establishing an understanding of the fundamental electromagnetic properties of 1D DBE and MPC crystals using the transfer matrix and spectral domain method of moments (MoM) computations. This is followed by numerical characterization of 3D DBE crystals via surface integral equations. Upon successful demonstration of the DBE mode for improved antenna performance, a measurement setup is presented to characterize low loss uniaxial materials. Subsequently, Specifically, a finite DBE assembly is built and shown to exhibit large aperture efficiency for conformal high gain antenna applications.;The second half of the dissertation introduces a novel coupled transmission line concept capable of emulating DBE mode on otherwise uniform microwave substrates. Using this novel dual transmission line concept, we present examples of several small antennas on low and high contrast substrates, and fabricate a prototype to experimentally verify the printed slow wave concepts. The measured DBE antenna is shown to perform better than other recently published metamaterial antennas. It is therefore very attractive for several RF applications requiring small and efficient antennas (such as RF identification (RFID) tags or mobile communications). The last chapter presents a lumped circuit DBE model and suggest improvement to existing DBE antennas by introducing lumped elements into the transmission lines.
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