Design of Pentagonal Fractal Antenna for Ultra Wideband Applications

Ultra Wide band fractal antenna based on pentagonal geometry has been proposed in this thesis. Fractal shapes and their properties are discussed. The proposed antenna is microstrip line fed and its structure is based on fractal geometry where the resonance frequency of antenna is lowered by applying iteration techniques. Analysis of fractal antenna is done by using Software named CST Microwave Studio Suite 12. This antenna has low profile, is lightweight and easy to be fabricated and has successfully demonstrated multiband and broadband characteristics. The antenna size inclusive of the ground plane is compact with dimensions 7 X 7 cm2 and has wide operating bandwidths of 8 GHz. The antenna exhibits omnidirectional direction radiation coverage with a gain from 2 to 6.5 dBi in the entire operating band. Measured results show that this antenna operates from 4.7 to 12.7 GHz with a fractional bandwidth of above 90% and has relatively stable radiation patterns over its whole operation band

Wireless body area networks: UWB wearable textile antenna for telemedicine and mobile health systems

Producción CientíficaA compact textile ultra-wideband (UWB) antenna with an electrical dimension of 0.24λo × 0.24λo × 0.009λo with microstrip line feed at lower edge and a frequency of operation of 2.96 GHz is proposed for UWB application. The analytical investigation using circuit theory concepts and the cavity model of the antenna is presented to validate the design. The main contribution of this paper is to propose a wearable antenna with wide impedance bandwidth of 118.68 % (2.96–11.6 GHz) applicable for UWB range of 3.1 to 10.6 GHz. The results present a maximum gain of 5.47 dBi at 7.3 GHz frequency. Moreover, this antenna exhibits Omni and quasi-Omni radiation patterns at various frequencies (4 GHz, 7 GHz and 10 GHz) for short-distance communication. The cutting notch and slot on the patch, and its effect on the antenna impedance to increase performance through current distribution is also presented. The time-domain characteristic of the proposed antenna is also discussed for the analysis of the pulse distortion phenomena. A constant group delay less than 1 ns is obtained over the entire operating impedance bandwidth (2.96–11.6 GHz) of the textile antenna in both situations, i.e., side by side and front to front. Linear phase consideration is also presented for both situations, as well as configurations of reception and transmission. An assessment of the effects of bending and humidity has been demonstrated by placing the antenna on the human body. The specific absorption rate (SAR) value was tested to show the radiation effect on the human body, and it was found that its impact on the human body SAR value is 1.68 W/kg, which indicates the safer limit to avoid radiation effects. Therefore, the proposed method is promising for telemedicine and mobile health systems.Gobierno del Pais Vasco - HAZITEK e IT-905-1

Ultra Wideband

Ultra wideband (UWB) has advanced and merged as a technology, and many more people are aware of the potential for this exciting technology. The current UWB field is changing rapidly with new techniques and ideas where several issues are involved in developing the systems. Among UWB system design, the UWB RF transceiver and UWB antenna are the key components. Recently, a considerable amount of researches has been devoted to the development of the UWB RF transceiver and antenna for its enabling high data transmission rates and low power consumption. Our book attempts to present current and emerging trends in-research and development of UWB systems as well as future expectations

Recent Techniques in Design and Implementation of Microwave Planar Filters

This paper details the techniques and initiatives made recently for improved response and simultaneous development of microwave planar filters. Although the objective of all the techniques is to design low cost filters with reduced dimensions, compact size with better frequency response, the methodological approaches are quite variant. The paper has gone through extensive analysis of all these techniques, their concept and design procedures

Miniaturized Microwave Devices and Antennas for Wearable, Implantable and Wireless Applications

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 Ph

Recent Advances in Antenna Design for 5G Heterogeneous Networks

The aim of this book is to highlight up to date exploited technologies and approaches in terms of antenna designs and requirements. In this regard, this book targets a broad range of subjects, including the microstrip antenna and the dipole and printed monopole antenna. The varieties of antenna designs, along with several different approaches to improve their overall performance, have given this book a great value, in which makes this book is deemed as a good reference for practicing engineers and under/postgraduate students working in this field. The key technology trends in antenna design as part of the mobile communication evolution have mainly focused on multiband, wideband, and MIMO antennas, and all have been clearly presented, studied and implemented within this book. The forthcoming 5G systems consider a truly mobile multimedia platform that constitutes a converged networking arena that not only includes legacy heterogeneous mobile networks but advanced radio interfaces and the possibility to operate at mm wave frequencies to capitalize on the large swathes of available bandwidth. This provides the impetus for a new breed of antenna design that, in principle, should be multimode in nature, energy efficient, and, above all, able to operate at the mm wave band, placing new design drivers on the antenna design. Thus, this book proposes to investigate advanced 5G antennas for heterogeneous applications that can operate in the range of 5G spectrums and to meet the essential requirements of 5G systems such as low latency, large bandwidth, and high gains and efficiencies

Design a Microstrip Patch Antenna for Ultra Wide Band (UWB) Applications

The development of Ultra Wide Band (UWB) technology, including antennas as an essential part of wireless communication systems, is greatly accelerated. However, there are more challenges in designing a UWB antenna more than a narrow band one. It should be capable of operating over an ultra-wide bandwidth as allocated by the Federal Communications Commission (FCC) from 3.1GHz to 10.6GHz. At the same time, the radiation properties over the entire frequency range are also necessary to be satisfactory. This thesis focuses on a designing a novel microstrip Ultra Wide Band (UWB) antenna for optimum performance like wide bandwidth, good matching impedance, small antenna size exhibits a good voltage standing wave ratio (VSWR) performance and its E– and H–plane radiation patterns are stable over the UWB frequency range and others. This antenna has a new patch shape that allows for providing good properties. Discussing the necessary parameters of UWB antennas, and studying the techniques of enhancing the bandwidth of a microstrip UWB are also investigated, to get antenna exhibit excellent performance of UWB characteristics with enhanced bandwidth. The first antenna studied in this thesis is a microstrip star-shape antenna which is a new shape and we call it (SSA) by using Ansoft’s HFSS software package. The antenna consists of a star-shape radiating element with a partial ground plane and a microstrip line feed from the edge of the patch. Feeding patch from edge consider as a method for enhancing the bandwidth as we will see later. The parameters structure of the antenna was optimized to achieve the widest antenna bandwidth and impedance matching. A parameter study was conducted to optimize antenna parameters. It helps to investigate the effect of different parameters on the impedance bandwidth. So our study are also includes studding the effect of feed line shift of microstrip line from center of patch to its edge and shows how it plays an important role with enhancing the bandwidth and reaches it to 18.6GHz (from 3.9GHz to 22.5GHz). Also the effect of the ground plane length is studied and shows how it serves as an impedance matching circuit and also it tunes the resonant frequencies. The effect of feed line width is also investigated. The second antenna studied is a slotted star shape antenna which has new ground plane shape. It consists of partial ground plane with multiple rectangular slots at top side of ground. This is another method for enhancing the bandwidth. Also the effect of the length and width of slots was studied, and shows how it has opposite effect on return loss value. The impedance bandwidth of this antenna is enhanced and reaches 20.6 GHz (3.9 GHz to 24.5 GHz). The properties of antenna namely; bandwidth, input impedance, radiation pattern and VSWR, were investigated for both antennas and show how we get good results for both

UWB linear array for 3D microwave imaging

Microwave imaging is being investigated by many research groups for its po- tential in medical diagnostic and treatment elds. Microwave signals are to sensitive to small changes into the dielectric properties of the objects under test which can be related to their physiological state. The use of UWB signals ( 3.1 - 10.6 GHz ) allow a good compromise between penetration and resolution. Moreover in the last years UWB frequency range has strongly exploited in med- ical imaging research eld, due to its characteristics of low-cost implementation and low-power used. The objective of this work is the design and the fabrication of multiplexed slot antenna array, that will be used in a 3D arrayed microwave tomographic system for medical imaging. This system is characterized by a rotation of mul- tiplexed linear antenna array around the object under test. With the aim of reducing the acquisition time it is replaced the vertical movement with a real antenna array. In the chapter 1 the introduction of medical imaging will be pre- sented and the system requirements are described. In the chapters 2 the basic concepts of UWB microstrip slot antennas and feeding methods will be analyzed respectively. In chapter 3 the individual array elements will be chosen and two array con gurations will be designed. In chapter 4 the feeding networks will be planned and simulated, the prototypes will be fabricated and the simulation data will be compared with measurement results. Finally the calibration will be done and the array con guration with the best performance will be chosen. In chapter 5 the conclusions will be deduced and the future works will be proposed

Design and analysis of wideband passive microwave devices using planar structures

A selected volume of work consisting of 84 published journal papers is presented to demonstrate the contributions made by the author in the last seven years of his work at the University of Queensland in the area of Microwave Engineering. The over-arching theme in the author’s works included in this volume is the engineering of novel passive microwave devices that are key components in the building of any microwave system. The author’s contribution covers innovative designs, design methods and analyses for the following key devices and associated systems: Wideband antennas and associated systems Band-notched and multiband antennas Directional couplers and associated systems Power dividers and associated systems Microwave filters Phase shifters Much of the motivation for the work arose from the desire to contribute to the engineering o