Recent years have seen a remarkable growth in wireless technology, e.g. mobile telephony, wireless local area network (WLAN), Bluetooth, Global Positioning Systems (GPS), and radio frequency identification devices (RFIDs). Given that many of these technologies operating at disparate frequency bands with different bandwidth, pattern, and polarization requirements are being packaged within a single wireless device created a tremendous need for miniature, wideband, highly efficient antennas. However, it is extremely difficult to overcome the challenges associated with achieving these objectives using conventional antenna design methodologies since antenna performance characteristics are largely dependent on its electrical dimensions. In this work the prospects of antenna miniaturization, bandwidth improvement and gain enhancement are studied by exploring a novel non-contact feeding scheme and the design and application of metamaterial loading.

A novel non-contact feeding technique to design two miniature embedded antennas is proposed followed by systematic studies on antenna design using metamaterial loading. A Method of Moments (MoM) analysis is performed on a finite length cylindrical dipole antenna enclosed by a homogenous Double Negative (DNG) metamaterial. The dipole exhibits wide bandwidth characteristics due to the relative insensitivity of the impedance with frequency. The dipole also shows resonance at much lower frequencies than its resonant frequency in free space. A new class of SRR (split ring resonator) geometry is introduced which by virtue of its increased inductance provides wider stopband bandwidth than existing SRRs available in the literature. A simple intuitive design methodology to design metamaterial structures is introduced which utilizes easy to use algebraic equations to predict the operating frequencies of such structures. Experimental prototypes are developed and tested to validate performance. Several applications of metamaterials are investigated experimentally, such as, wireless power transmission to a buried sensor rectenna in concrete, antenna bandwidth improvement, and near field energy focusing.