Design, reconfiguration and analysis of antenna systems for mobile and IoT devices.

Abstract

With the rapid development of wireless communication systems, and the rise of the age of internet of things (IoT), the requirements on communication systems are increasing significantly. In fact, radio frequency (RF) front end systems will be responsible for the communication needs of billions of devices by 2025. Therefore, designers and researchers are seeking compact multi-functional transceiver systems that cater for the pressing wireless communication needs, while at the same time preserving the respective standards' requirements. The various transceiver components including antenna elements must be compact, adaptive, tunable, and at the same time high performing. Such requirements present a challenge for antennas and RF designers worldwide. Therefore, this dissertation discusses a holistic solution that designs a full reconfigurable communication system for mobile and IoT devices. Such solution starts with an analysis of the different switching techniques and their effects on an antenna performance. More specifically, the impact of positive-intrinsic-negative (PIN) diodes, Radio Frequency micro-electromechanical switch (RF MEMS), varactors and digital tunable capacitors (DTC) on an antenna's gain, power dissipated, radiation efficiency, linearity and switches' biasing requirements are evaluated and compared. Such analysis allows antenna designers to always commit to an informed decision on the reconfiguring component’s choice during the early stages of the design process. This analysis is first executed on a novel reconfigurable multiple input multiple output (MIMO) printed inverted F antenna (PIFA) system. The PIFA elements are reconfigured by relying on PIN diodes, RF MEMS, or varactors in order to cover the needed frequencies of operation, as well as radiation requirements that are necessary in mobile and compact terminals. In addition, the isolation between the antenna elements of the proposed MIMO system is also reconfigured by relying on a reconfigurable band reject filter that is incorporate