Wireless communication is ubiquitous as we are in the cusp of intelligent connectivity (e.g., fifth-generation (5G) and internet of things (IoT)), autonomous devices, advance satellite communications, millimeter-wave communications, and augmented reality. The technology demands exploration in cost-effective and energy-efficient antenna technologies to facilitate the transformation of these innovations. This dissertation is the collection of research on novel high gain feed-reflector and beam steering antenna solutions to meet these futuristic demands in satellite and wireless communications. As part of the dissertation, following significant antenna research contributions have been made to facilitate the high data throughput for satellite and wireless communication networks: (1) W-band (79 – 88 GHz) novel circularly polarized feed horn antenna feeding an offset parabolic reflector for CubeSats; (2) W-band (86 GHz) fixed-beam novel circularly polarized series-fed novel Butterfly antenna and 1D-beam steering phased array antenna for CubeSats; (3) Ku-band (12 – 14 GHz) dual-linear polarized 1D-beam steering parabolic-cylindrical reflector fed by a silicon RFIC transceiver based flat panel phased array antenna; (4) Multi-functional Ka-band (28 GHz) staggered Butterfly array antenna for 5G communications with key features of full-polarization reconfigurability, flexible radiation pattern, and wide-angle 1D-beam steering performance; and (5) Investigation on the Ka-band (26.5 – 29.5 GHz) 3D metal printed dual circularly polarized feed-horn feeding a spherical reflector for high gain multiple-beam switching applications. The relevant computational methods used in the research are computational electromagnetics, physical optics (PO), linear algebra, Monte-Carlo statistical analysis, and beam synthesis algorithm. Discussion about the proposed antennas include detailed theoretical analysis, numerical simulation, optimizations, beam synthesis algorithms, fabrication of the antennas and its control/beamforming feed networks, and finally, its characterization of impedance matching, gain, and radiation patterns.