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In this report, radiation of sources inside layered media backed by a perfect electric conductor were studied. This problem has practical applications to antennas embedded inside composite material media for many applications. The traditional real-axis integration method was employed with a new formulation for calculating the Sommerfeld integral tail. This new method contains effects of the intrinsic wavenumber of the layer and hence appears physically more suitable for understanding effects of the various layers when the observation point moves in a vertical direction from one layer to the other. In addition, a new algorithm was developed to calculate the proper surface wave poles for electrically thick substrates. The discontinuities in the integrand of the Sommerfeld integral were eliminated upon subtraction of the residues at these poles, and subsequent numerical integration posed no difficulties. Additionally, the problem of stratified media was studied via the phase-integral method. It has been shown that the phase-integral method, with its attendant asymptotic expansions, has the potential for providing much improved solutions to the Green's functions for continuously stratified media by including effects across the Stokes lines., Prepared in collaboration with the School of Computing and Engineering, University of Missouri Kansas City, Kansas City, Missouri.

Futuristic wireless communication systems must perform in environments that generate scattering from various obstacles which in turn cause multipath effects to be dominant. This results in degradation in the overall performance that can be avoided if the antennas have narrow beamwidths and low sidelobes. Advanced designs for Rapidly Deployable Radio Network (RDRN) systems are required to consider transmission at single frequency to several mobile users in a single frequency cell. This in turn requires narrow beam, low-sidelobe antenna patterns in order to obtain diversity between closely located users in a single cell. In this report analysis of an array of lambda/2, axial, electric dipoles radiating in presence of a conducting cylinder is presented. The amplitude excitations are determined by Hamming and Taylor distributions while the phase excitations are determined by using an even symmetric quadratic phase taper. Once the complex excitations were found the far-field patterns were computed via the Numerical Electromagnetics Code - Basic Scattering Code (NEC-BSC). The mutual coupling has not been considered in this report. The results show that an interelement spacing between 0.4 lambda and 0.6 lambda may be chosen in order to avoid appearence of higher peaks close to the boresight mainbeam. This criterion has also been used to propose an algorithm to design the array geometry and the complex excitations. It was found that even symmetric phase taper provided superior pattern topography in addition to the amplitude taper. Indepenent control of the amplitude and phase excitations indicate that the Digital BeamForming (DBF) technique can be used to design high-performance cylindrical arrays.