| The primary focus of this dissertation is on the analyses of self-resonant bent antennas. The need for the accurate characterization of such antennas due to their growing importance in present day wireless communications is the motivation for this work. To this end, several self-resonant bent antennas are analyzed which includes an inverted-L antenna (ILA), a meander-line dipole (MLD) antenna, a meander-line bow-tie (MLBT) antenna, a dual meander antenna, and a printed meander antenna.;A simple analytical model, based on the induced EMF method, is presented to compute the input impedance of the ILA. First, a sinusoidal distribution of current on the antenna, with zero current at the end is assumed, and then an expression for the input impedance is derived using the near-fields of the antenna. The accuracy of the formulation is verified by comparing the results computed using it with that from NEC [1] computation. Unlike the analytical solutions available in the literature, our proposed solution is not restricted to antennas that are electrically small. In addition the new formulation can be extended to treat other antennas, such as the T-antenna, the folded unipole antenna, and the loop-loaded monopole antenna.;The input impedance, radiation pattern, and gain of the MLD and MLBT antennas axe computed and correlated with their parameters. Input impedances of both antennas are computed using NEC. Simple analytical models are presented to compute the radiation patterns of the MLD and the MLBT antennas. For each antenna, a sinusoidal distribution of current is assumed and closed-form expressions for the radiation fields are derived. The results computed using the analytical models are verified by comparing them with the results from the NEC computation. Since in each model the radiation pattern of an antenna is expressed in terms of evaluate algebraic expressions, the computation of such pattern is fast and easy.;The input impedance and radiation characteristics of a dual meander antenna are computed using NEC. Similarly as before the input impedance, radiation pattern, and gain of this antenna axe also correlated with its parameters. The input impedance and radiation pattern of a planar printed meander antenna are investigated using the Finite-Difference Time-Domain (FDTD) technique. The antenna is modeled on a dielectric substrate both in the presence and absence of a metallic ground plane. Characteristics of the antenna are examined as function of dielectric constant, and substrate thickness. New results of input impedance, radiation pattern, and gain axe presented which are vital for the design of such antennas.;Several novel applications of self-resonant bent antennas are described. (Abstract shortened by UMI.). |
