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In this paper, we introduce a novel hybrid multiuser multiple-input multiple-output (MU-MIMO) architecture, with an emphasis on aggressive millimeter-wave (mmWave) hardware reduction methods, omitting the beam selection stage. We propose a simplification in a 28 GHz Rotman lens, where the number of beam-ports are reduced relative to the array ports resulting in the removal of a bank of RF switches and its associated biasing network. We conducted full electromagnetic characterization of imperative lens defects and precisely quantify the expected loss. For the first time, it is shown that the beam-port decimation greatly reduces the total EM aberrations, and consequently increases the focusing capability of the lens. With maximum-ratio (MR) baseband processing, we study uplink signal-to-interference-plus-noise ratio (SINR) of a user terminal, and evaluate the sum spectral efficiency performance of the proposed system assuming a 28 GHz double-directional propagation channel. The performance of the proposed system is compared with the classical system include the beam selection network. Although the performance of the proposed architecture is sub-optimal relative to the conventional case, we demonstrate that it greatly simplifies the practical realizations of the mmWave RF front-ends, while still maintaining highly desirable and useful operational characteristics.

This thesis presents a number of microwave devices and antennas that maintain high operational efficiency and are compact in size at the same time. One goal of this thesis is to address several miniaturization challenges of antennas and microwave components by using the theoretical principles of metamaterials, Metasurface coupling resonators and stacked radiators, in combination with the elementary antenna and transmission line theory. While innovating novel solutions, standards and specifications of next generation wireless and bio-medical applications were considered to ensure advancement in the respective scientific fields. Compact reconfigurable phase-shifter and a microwave cross-over based on negative-refractive-index transmission-line (NRI-TL) materialist unit cells is presented. A Metasurface based wearable sensor architecture is proposed, containing an electromagnetic band-gap (EBG) structure backed monopole antenna for off-body communication and a fork shaped antenna for efficient radiation towards the human body. A fully parametrized solution for an implantable antenna is proposed using metallic coated stacked substrate layers. Challenges and possible solutions for off-body, on-body, through-body and across-body communication have been investigated with an aid of computationally extensive simulations and experimental verification. Next, miniaturization and implementation of a UWB antenna along with an analytical model to predict the resonance is presented. Lastly, several miniaturized rectifiers designed specifically for efficient wireless power transfer are proposed, experimentally verified, and discussed. The study answered several research questions of applied electromagnetic in the field of bio-medicine and wireless communication., Comment: A thesis submitted for the degree of PhD