This thesis deals with Symbol Error Rate (SER)-simulation of wireless communications and its application into throughput analysis of UltraWideband (UWB) systems. The SERs will be simulated in C++ using the Monte Carlo method and when some are calculated, the rest will be estimated using a novel extrapolation method. These SER values will be very accurate and in this thesis go as low as 1.0e-14. Reaching that low values would otherwise be impossible using the traditional Monte Carlo method, because of very large computation time. However, the novel extrapolation method, can simulate a SER-curve in less than 30 seconds. It is assumed that the noise belongs to the Generalized Gaussian distribution family and among them noise from the Normal distribution (Gaussian noise) gives the best result. It is to be noted that Gaussian noise is the most commonly used in digital communication simulations. Although the program is used for throughput analysis of UWB, the program could easily be adapted to various signals. In this thesis, throughput analysis means a plot with symbol rate vs distance. From any given symbols, the user can, with a desired minimum SER, generate an extrapolated SER-curve and see what symbol rate can be achieved by the system, while obeying power constraints of signals imposed by international laws. The developed program is, by comparing with published theoretical results, tested for QAM and PSK cases, but can easily be extended to UWB systems.

Novel microwave transmitter and receiver circuits have been developed for implementing UWB (Ultra-Wideband) impulse radar imaging sensor operating in frequency band 0.2 to 4 GHz. with tunable operating frequency band. The fundamental system design parameters such as the required transmitting pulse power and the pulse duration were estimated for a presumed specific application, the pavement assessment. The designed transmitter is the tunable monocycle pulse generator with tuning capability for the output pulse duration from 450- to 1200- ps, and has relatively high transmitting pulse power from 200 to 400 mW. Tuning of the pulse duration was implemented by novel PIN diode switch configuration and decoupling circuit, and boosting of transmitting pulse power was made possible by using a high power pulse driving circuit and SRD coupling circuit. The synchronous sampling receiver system was designed by using the integrated sampling mixer and two reference clock oscillators placed in the transmitter and receiver respectively for timing control. A novel integrated CSH (Coupled-Slotline Hybrid)sampling mixer has been developed along with the design of the strobe pulse generator appropriate for the impulse radar system. The integrated sampling mixer has unprecedented conversion loss of 2.5 dB for the pulse signal, bandwidth 5.5 GHz, and dynamic range 50 dB. The introduced UWB LNA (Low Noise Amplifier) design operating up to 4 GHz should be useful for weak signal detection applications. The design of the UWB microstrip quasi-horn antenna was optimized for short pulse transmission with respect to the input return loss and the pulse stretching effect. For signal detection in the signal processing stage, the background subtraction technique and B-scan data format were used. A novel signal monitoring technique was introduced in the signal processing to compensate the frequency modulation effect of the reference clock. The test results for the complete system with respect to some sample multi-layer structures shows good receiving pulse waveform with low distortion, enough pulse penetration depth for 13” pavement sample structure, and minimum 1-in of range resolution.

Thesis (M.S.)--Tennessee Technological University, 2009. / Title from title page screen (viewed on Feb. 9, 2010). Bibliography: leaves 102-108.

Σκοπός αυτής της διπλωματικής εργασίας είναι η μελέτη, σχεδίαση και εξομοίωση τυπωμένων υπερευρυζωνικών κεραιών, κατάλληλων για χρήση σε ασύρματα δίκτυα προσωπικού χώρου. Στο πρώτο κεφάλαιο, ορίζονται βασικές έννοιες της θεωρίας κεραιών που είναι απαραίτητες για την κατανόηση των κεφαλαίων που ακολουθούν. Επιπλέον, γίνεται μια μικρή αναφορά στο πρόγραμμα ADS Momentum που χρησιμοποιήσαμε κατά την εξομοίωση των κεραιών. Στο δεύτερο κεφάλαιο, παρουσιάζονται τα ιδιαίτερα χαρακτηριστικά, η ιστορική εξέλιξη, τα πλεονεκτήματα καθώς και οι σημαντικότερες εφαρμογές της υπερευρυζωνικής τεχνολογίας Στο τρίτο κεφάλαιο, περιγράφονται οι επιθυμητές ιδιότητες των υπερευρυζωνικών κεραιών, κάποιες τεχνικές επίτευξης προσαρμογής σε μεγαλύτερο εύρος συχνοτήτων και παράμετροι βέλτιστου σχεδιασμού των στοιχείων. Εν συνεχεία, γίνεται αναφορά σε όλες τις κατηγορίες υπερευρυζωνικών κεραιών και τέλος παρατίθενται παραδείγματα για κάθε μία από τις τρεις κατηγορίες τυπωμένων κεραιών που θα εξετάσουμε. Στο τέταρτο κεφάλαιο, μελετώνται οι μονοπολικές τυπωμένες υπερευρυζωνικές κεραίες. Για τον σκοπό αυτό σχεδιάστηκαν και εξομοιώθηκαν δύο μονοπολικές κεραίες κυκλικού δίσκου τροφοδοτούμενες, η πρώτη από μικροταινιακή γραμμή και η δεύτερη από ομοεπίπεδο κυματοδηγό. Στο πέμπτο κεφάλαιο, μελετώνται οι διπολικές τυπωμένες υπερευρυζωνικές κεραίες. Για τον σκοπό αυτό σχεδιάστηκε και εξομοιώθηκε η δίπλευρη τυπωμένη κεραία παπιγιόν αλλά και η τυπωμένη ελλειπτική διπολική κεραία. Στο έκτο κεφάλαιο, μελετώνται οι τυπωμένες κεραίες σχισμής. Για τον σκοπό αυτό σχεδιάστηκαν και εξομοιώθηκαν δύο ελλειπτικές κεραίες σχισμής τροφοδοτούμενες η πρώτη από μικροταινιακή γραμμή και η δεύτερη από ομοεπίπεδο κυματοδηγό. Επιπλέον οι γραμμές μεταφοράς των κεραιών καταλήγουν σε stub διαφορετικού σχήματος. Στο έβδομο, τέλος, κεφάλαιο γίνεται μια συνοπτική παρουσίαση των αποτελεσμάτων, ενώ παρατίθενται συμπεράσματα και προτάσεις για μελλοντική ενασχόληση πάνω στο θέμα των τυπωμένων υπερευρυζωνικών κεραιών. / The present diploma thesis will focus on the study, design and simulation of printed Ultrawideband antennas. These antennas are suitable for high data rate wireless personal area networks. The first chapter includes key definitions of antenna theory. Moreover, the program ADS Momentum that was used during the simulations is presented. In the second chapter, we present the key attributes, the advancement, the advantages and the most crucial applications of UWB technology. The third chapter depicts the desirable attributes of UWB antennas. In addition, some common matching, and element design techniques are presented. Furthermore, Ultrawideband antenna categories are introduced. Finally, some interesting examples of printed Ultrawideband antennas are mentioned. In the fourth chapter, printed UWB monopole antennas are being studied. For this purpose two printed circular disc monopole antennas were designed and simulated. The former fed by a microstrip line and the latter by a coplanar waveguide. In the fifth chapter, printed UWB dipole antennas are being studied. A double sided printed bow tie antenna and an elliptical dipole antenna were designed and simulated. In the sixth chapter, printed UWB slot antennas are being studied. For this purpose two printed elliptical slot antennas were designed and simulated. The former fed by a microstrip line and the latter by a coplanar waveguide. Finally, the seventh chapter includes a comparison of the simulated antennas along with conclusions and proposed future work.

Ultra wideband (UWB) systems have the potential for high data rate applications such as high-definition video streaming, high speed data transfer, etc. Recently, WiMedia based UWB evaluation systems and commercial products are available from industry. In order to understand the true performance of the WiMedia UWB system, it is important to study its characteristics from mathematical models and practical measurement tests. One of the key objectives of this thesis is to determine the important parameters in the path loss model based on the measurement results from the intended environments. Our focus is on residential environments including office buildings and houses, where intensive measurements are performed from various layers of a network (e.g. physical layer, packet level and application level). The results show that the WiMedia UWB system is fully capable of handling different high rate applications in residential networks. Another goal of this thesis is to propose a medium access control (MAC) protocol design tailored to high rate residential UWB wireless networks. The proposed multiband distributed MAC design utilizes the unique capabilities of UWB technology and the environment characteristics. We elaborate the design details and build a discrete event simulation program for performance evaluation purpose. By evaluating from both theoretical analysis and simulation, we show that the proposed MAC design has substantial advantage over single channel MAC in a high rate residential UWB wireless network. / Graduate

Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.

Thesis (Ph.D.)--Tennessee Technological University, 2008. / Bibliography: leaves 106-112.

Thesis (Ph.D.)--Tennessee Technological University, 2008. / Includes bibliographical references.

Thesis (Ph. D.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 80-84). Also available on the World Wide Web.

Thesis (Ph. D.)--University of Hong Kong, 2005. / Title proper from title frame. Also available in printed format.