A Sliding Correlator Channel Sounder for Ultra-Wideband Measurements

This body of work forms a detailed and comprehensive guide for those interested in performing broadband wireless channel measurements. Discussion addresses the theoretical and practical aspects of designing and implementing a sliding correlator channel sounder, as well as how such a system may be used to measure and model the ultra-wideband wireless channel. The specific contributions of this work are as follows: Developed a systematic methodology for designing optimal sliding correlator-based channel sounders. Constructed a UWB channel sounder based upon a 17-bit LFSR that attained 1.66 ns of temporal resolution and 34 dB of dynamic range. Performed an exemplary measurement campaign of the UWB channel from which UWB angular spreads and RMS delay spreads are reported. The design procedure developed in Chapter 3 will allow researchers to build optimal channel sounders for investigating next-generation wireless channels. Chapter 4 s discussion addresses the real-world challenges of constructing a high performance sliding correlator channel sounder. Finally, the measurement campaign discussed in Chapter 5 outlines a procedure for investigating the spatio-temporal characteristics of the wireless channel and provides some of the first examples of UWB angular spread measurements.M.S.Committee Chair: Durgin, Gregory; Committee Member: Ingram, Mary Ann; Committee Member: Smith, Whi

Analysis and Design of Footwear Antennas

Wearable technologies are found in an increasing number of applications including sport and medical monitoring, gaming and consumer electronics. Sensors are used to monitor vital signs and are located on various parts of the body. Footwear sensors permit the collection of data relating to gait, running style, physiotherapy and research. The data is sent from sensors to on-body hubs, often using wired technology, which can impact gait characteristics. This thesis describes the design of footwear antennas for wireless sensor telemetry. The work addresses the challenges of placing antennas close to the foot as well as the proximity to the ground. Guidelines for polarization are presented. The channel link between footwear and wrist is investigated for both narrowband and wideband channels across different frequencies. The effects of the body proximity and movement were gauged for walking subjects and are described in terms of the Rician Distribution K-factor. Different antenna solutions are presented including UWB antennas on various footwear locations as well as 433 MHz integrated antennas in the insole. Both directional and omnidirectional antennas were considered for UWB and the evaluation was for both time-domain and frequencydomain. The research established new ideas that challenge the old paradigm of the waist as the best hub position, demonstrating that a hub on the footwear using directional antennas outperforms a hub on the waist using an omnidirectional antenna. The cumulative distribution functions of measured path gains are evaluated and the results are described in terms of the achievable minimum data rate considering the Body Area Network standard

A Fully Differential Digital CMOS Pulse UWB Generator

A new fully-digital CMOS pulse generator for impulse-radio Ultra-Wide-Band (UWB) systems is presented. First, the shape of the pulse which best fits the FCC regulation in the 3.1-5 GHz sub-band of the entire 3.1-10.6 GHz UWB bandwidth is derived and approximated using rectangular digital pulses. In particular, the number and width of pulses that approximate an ideal template is found through an ad-hoc optimization methodology. Then a fully differential digital CMOS circuit that synthesizes the pulse sequence is conceived and its functionality demonstrated through post-layout simulations. The results show a very good agreement with the FCC requirements and a low power consumptio

Footwear Antennas for Body Area Telemetry

Antennas designed to link footwear sensors within body centric networks are introduced with two small UWB antennas, one directional and another quasi-omnidirectional. The radiating characteristics are evaluated for three positions on a sample sports shoe using a detailed simulation model and measurements with a homogenous foot phantom. Antenna performance is assessed for resilience to close proximity loading by the footwear materials and the phantom foot

UWB Technology

Ultra Wide Band (UWB) technology has attracted increasing interest and there is a growing demand for UWB for several applications and scenarios. The unlicensed use of the UWB spectrum has been regulated by the Federal Communications Commission (FCC) since the early 2000s. The main concern in designing UWB circuits is to consider the assigned bandwidth and the low power permitted for transmission. This makes UWB circuit design a challenging mission in today's community. Various circuit designs and system implementations are published in this book to give the reader a glimpse of the state-of-the-art examples in this field. The book starts at the circuit level design of major UWB elements such as filters, antennas, and amplifiers; and ends with the complete system implementation using such modules

Small and Compact Double E-shaped Meander Line Monopole Antenna for Forward Scatter Radar Network

A small and compact printed monopole antenna can be obtained by introducing double E-shaped meander line patch backed by a partial ground plane. The double E-shaped meander line patch reduces the antenna resonant frequency so that the size of the antenna can be reduced for targeted frequency of 400 MHz specific for Forward Scatter Radar (FSR) Network. 77% size reduction of the antenna has been successfully achieved where the overall size of the proposed antenna is only 93.8 x 131 mm2 (0.125λ0 x 0.175λ0) compared to before it was reduced which is 190.7 x 276.3 mm2 (0.25λ0 x 0.368λ0). The size reduction is obtained without significant effects on other antenna performances. The proposed antenna produces high measured efficiency of 85.5% and measured gain of 0.3 dBi with an omnidirectional radiation pattern. A comprehensive parametric study is accomplished to obtain the best performances of the antenna. For a better understanding on the design characteristics, an equivalent circuit model is derived carefully

Antennas and Propagation

This Special Issue gathers topics of utmost interest in the field of antennas and propagation, such as: new directions and challenges in antenna design and propagation; innovative antenna technologies for space applications; metamaterial, metasurface and other periodic structures; antennas for 5G; electromagnetic field measurements and remote sensing applications

Computational Electromagnetic Studies for Low-Frequency Compensation of the Reflector Impulse-Radiating Antenna

The reflector impulse-radiating antenna (IRA) is considered to meet the requirement for a wideband, directional antenna with short temporal response and small electrical footprint. Standard reflector IRA designs are modeled and performance is simulated using full-wave computational electromagnetic (CEM) software. Characterization of the standard designs reveals the possible existence of wide, frequency-independent backlobes containing nearly 40% of the radiated power at high frequencies. These undesirable backlobes have never been hypothesized, predicted or measured, likely due in part to their alignment outside the primary measurement planes. At the lowest operating frequencies, the reflector IRA is unaffected by backlobes, but is characterized by low radiation efficiency and high resistive losses. Simulated studies are conducted to identify options for enhancing the low-frequency performance of the reflector IRA, including novel multi-arm feed structures and varied resistor distributions and values in the matching circuit component of the antenna design. Both techniques are predicted to provide viable options for enhancing and tuning the performance of the reflector IRA at low frequencies

Design, Realization and Measurements of Compact Dual-band CPW-fed Patch Antenna for 2.45/5.80 GHz RFID Applications

In this paper, a Coplanar Wave Guide (CPW)-Fed microstrip octagonal patch antenna for RFID Applications is proposed. The studied structure is suitable for 2.45/5.80 GHz applications. The octagonal shape is obtained by making triangular cuts in the four angles of the rectangular microstrip patch antenna; in addition the using of CPW-Fed allows obtaining UWB characteristics in the higher band. The miniaturization in the antenna size for lower band is achieved by introducing an inverted E slot in the radiating element. The proposed antenna is designed on a single and a small substrate board of dimensions 29.5×29.5×1.6 mm3. Moreover the miniaturized antenna has a good impedance matching and an enhanced gain. The simulation analysis was performed using the CADFEKO software, a Method of Moment (MoM) based solver, and a prototype of this antenna was fabricated, good agreement with the simulation providing validation of the design procedure. The measurements are done with ANRITSU MS2026C Vectorial Network Analyzer

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