abstract: Articially engineered two-dimensional materials, which are widely known as metasurfaces, are employed as ground planes in various antenna applications. Due to their nature to exhibit desirable electromagnetic behavior, they are also used to design waveguiding structures, absorbers, frequency selective surfaces, angular-independent surfaces, etc. Metasurfaces usually consist of electrically small conductive planar patches arranged in a periodic array on a dielectric covered ground plane. Holographic Articial Impedance Surfaces (HAISs) are one such metasurfaces that are capable of forming a pencil beam in a desired direction, when excited with surface waves. HAISs are inhomogeneous surfaces that are designed by modulating its surface impedance. This surface impedance modulation creates a periodical discontinuity that enables a part of the surface waves to leak out into the free space leading to far-eld radia- tion. The surface impedance modulation is based on the holographic principle. This dissertation is concentrated on designing HAISs with Desired polarization for the pencil beam Enhanced bandwidth Frequency scanning Conformity to curved surfaces HAIS designs considered in this work include both one and two dimensional mod- ulations. All the designs and analyses are supported by mathematical models and HFSS simulations. / Dissertation/Thesis / Doctoral Dissertation Electrical Engineering 2017