Contents

**Preface XI**


Preface

applications of UWB systems.

Ultra-wideband (UWB) technology is a radio technology that uses electromagnetic waves with a very low power spectral density occupying a bandwidth of more than 25% of a centre frequency, or more than 0.5GHz, for short-range remote sensing, high-bandwidth communi‐ cations or object positioning. As UWB systems exploit a very large frequency band, they can provide high-range resolution for sensors, radars, object positioning and a high transmission rate for wireless communication systems. This feature of UWB technology has motivated researchers to develop a range of interesting applications of UWB systems. They include person localization and tracking at security operation and disaster events, contactless moni‐ toring of breathing frequency and heart rate of human beings, medical and industrial appli‐ cations of microwave imaging, ground penetrating and automotive radars, positioning

The detailed analyses of state-of-the-art UWB technology has shown that UWB technology can be considered very interesting, promising and having great application potential. Fol‐ lowing these facts, our book attempts to present current and emerging trends in research and development of UWB systems as well as some future expectations. The book consists of five chapters. The chapters are focused on basic components of UWB systems and on some

The first chapter is devoted to early detection of cancers using UWB technology. By early detection, we mean identification of tumours before the symptoms become visible. This can be done clinically using modern instrumentation and procedures referred to as screening. In this field, UWB microwave imaging has been introduced as a possible tool for replacing pri‐ or screening techniques such as X-rays, ultrasound and MRI to be applied for cancer detec‐ tion. Following this idea, the chapter compares UWB technology with other screening techniques to be applied for cancer detection. Moreover, selected properties of human tis‐

In the next chapter, an overview of the fundamental applications of frequency selective surfa‐ ces (FSS) in antenna engineering is presented. Here, special attention is paid to antennas for UWB systems employing FSS. In this field, the basic FSSs such as the capacitive and its com‐ plementary inductive FSSs to design UWB reflectors that can serve improving and stabilizing the gain of UWB antennas are considered. Thereafter, a proposed UWB single-layer FSS is used to serve the same purpose. And finally, the FSS is integrated and designed together with

It is well known that bandpass filters such as resonators (stub-loaded resonator, slot-line res‐ onator, multi-mode resonator) and notch filters are an essential part of UWB systems. These components of UWB systems are studied in the third chapter. The chapter is focused on mi‐

UWB radiators, which has resulted in lower profile along with a good performance.

systems, impedance spectroscopy, wireless communication systems, etc.

sues allowing identification of tumours are studied in the chapter.
