This work focuses on the analysis and design of multiple element antennas (MEA) and their interaction with the propagation channel. In particular, attention is given to urban channels and how its information throughput, i.e. capacity, can be improved. With this in mind, this work extends an existing network model of the communication system in order to reduce computation time, investigates the communicational limits of MEA systems and proposes a synthesis method for capacity maximization.

Ultra-Wideband Radio (UWB) earmarks a new radio access philosophy and exploits several GHz of bandwidth. It promises high data rate communication over short distances as well as innovative radar sensing and localization applications with unprecedented resolution. Fields of application may be found, among others, in industry, civil engineering, surveillance and exploration, for security and safety measures, and even for medicine. The book considers the basics and algorithms as well as hardware and application issues in the field of UWB radio technology for communications, localization and sensing based on the outcome of DFG's priority-funding program "Ultra-Wideband Radio Technologies for Communications, Localization and Sensor Applications (UKoLoS)".

The aim of this work is the development of a Radar system for consumer applications. It is capable of tracking multiple people in a room and offers a touchless human-machine interface for purposes that range from entertainment to hygiene.

In this work, new concepts of body-matched antennas for microwave medical applications were developed, where the antennas are placed directly on or in the human body. Two types of antennas were designed - on-body matched antennas for diagnosis and implantable antennas for data telemetry with the main focus of miniaturization yet maintained a high radiation performance. The applicability of the antennas was verified using a medical imaging system for the detection of hemorrhagic stroke.

The goal of this work is the introduction of efficient antenna structures on the basis of the requirement of different microwave imaging methods; i.e. quantitative and qualitative microwave imaging techniques. Several criteria are proposed for the evaluation of single element antenna structures for application in microwave imaging systems. The performance of the proposed antennas are evaluated in simulation and measurement scenarios.

Accompanied with the development of the wireless communication technologies, the high data traffic is more necessary for civil and industrial applications than ever The concept of an intelligent reflective surface (IRS) has attracted considerable attention recently as a low-cost solution. As the main contribution, the dissertation creates new state-of-the-art and formulates a solid milestone for the IRS research field.