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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

Effective beam width of directional antennas in wireless ad hoc networks.

January 2006 (has links)
Zhang Jialiang. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 51-52). / Abstracts in English and Chinese. / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Motivation and Related Work --- p.1 / Chapter 1.2 --- Organization of the Thesis --- p.3 / Chapter Chapter 2 --- Interference Modeling for Directional Antennas --- p.5 / Chapter 2.1 --- Pair-wise Physical Link Interference Model of Generic Directional Antenna --- p.6 / Chapter 2.2 --- Potential Interference Region --- p.8 / Chapter 2.3 --- Antenna Pattern and Phased Array Antenna --- p.9 / Chapter Chapter 3 --- Null Width of Directional Antennas --- p.12 / Chapter 3.1 --- Concept of Null Width --- p.12 / Chapter 3.2 --- Effective Null Width and Interference --- p.14 / Chapter 3.2.1 --- Probability of Interference --- p.14 / Chapter 3.2.2 --- Scenario of Directional Transmission and Omni-directional Reception --- p.15 / Chapter 3.2.3 --- Scenario of Directional Transmission and Directional Reception --- p.17 / Chapter 3.3 --- Properties of General Effective Beam Width --- p.18 / Chapter 3.4 --- Numerical Scaling Law of Effective Beam Width of Some Particular Antenna Patterns --- p.23 / Chapter 3.5 --- Summary --- p.26 / Chapter Chapter 4 --- Scaling Law of Network Capacity of Wireless Random Networks with Directional Antennas --- p.27 / Chapter 4.1 --- Random Network Model and Network Capacity --- p.27 / Chapter 4.2 --- Node distribution and MAC Protocol --- p.29 / Chapter 4.3 --- Scenario of Directional Transmission and Omni-directional Reception --- p.30 / Chapter 4.3.1 --- Probability of Transmission to be Success and Per-Link (Transport) Throughput --- p.30 / Chapter 4.3.2 --- Scaling Law of Network Capacity --- p.32 / Chapter 4.3.3 --- Concluding Remark --- p.37 / Chapter 4.4 --- Scenario of Directional Transmission and Directional Reception --- p.38 / Chapter 4.4.1 --- Antenna Steering Protocol --- p.39 / Chapter 4.4.2 --- Probability of Transmission to be Success --- p.40 / Chapter 4.4.3 --- Scaling Law of Network Capacity --- p.41 / Chapter 4.4.4 --- Scaling Law of Phased Array Antennas --- p.42 / Chapter Chapter 5 --- Conclusion --- p.44 / Appendix A: Proof of equation (22) --- p.47 / Appendix B: Proof of equation (28) --- p.49 / Appendix C: Constraint on Region of Optimality for pt and r --- p.50 / References --- p.51
102

A multilayeredly rolled inverted-F antenna for dual-band mobile phones.

January 2008 (has links)
Lam, Fuk Ming. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references. / Abstracts in English and Chinese. / Abstract --- p.I / Acknowledgements --- p.V / Table of Contents --- p.VI / List of Figures --- p.IX / List of Tables --- p.XVI / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Background --- p.1 / Chapter 1.2 --- Overview of the Work --- p.5 / Chapter 1.3 --- Original contribution of this thesis --- p.6 / Chapter 1.4 --- Organization of this thesis --- p.7 / Chapter 1.5 --- Remarks on frequency dependent parameters in this thesis --- p.8 / Reference --- p.9 / Chapter Chapter 2 --- Small Antennas for mobile phone applications --- p.10 / Chapter 2.1 --- Introduction --- p.10 / Chapter 2.2 --- Definitions --- p.11 / Chapter 2.2.1 --- Quality factor --- p.11 / Chapter 2.2.2 --- Efficiency --- p.12 / Chapter 2.2.3 --- Return Loss and impedance bandwidth --- p.12 / Chapter 2.2.4 --- Antenna gain and radiation pattern --- p.13 / Chapter 2.3 --- Fundamental limitations of small antenna --- p.14 / Chapter 2.4 --- Low-profile and Dual-band techniques --- p.16 / Chapter 2.4.1 --- Inverted-L/F and Planar Inverted-F Antenna --- p.16 / Chapter 2.4.2 --- Dual-band PIFA --- p.21 / Chapter 2.4.3 --- Discussion on miniaturization of mobile phone antenna --- p.23 / Chapter 2.5 --- Ground plane effect of mobile phone antenna --- p.26 / Chapter 2.5.1 --- Optimal location to excite antenna over a finite ground plane --- p.26 / Chapter 2.5.2 --- Dependence of resonant frequency and impedance bandwidth on ground plane length --- p.27 / Chapter 2.5.3 --- Dual-resonator model for mobile phone antenna --- p.32 / Chapter 2.6 --- Summary --- p.38 / Reference --- p.38 / Chapter Chapter 3 --- A Multilayeredly Rolled Inverted-F Antenna for Dual-band Mobile Phones --- p.42 / Chapter 3.1 --- Introduction --- p.42 / Chapter 3.2 --- Literature review on rolled antennas --- p.43 / Chapter 3.3 --- Proposed MRIFA --- p.47 / Chapter 3.3.1 --- Antenna configuration --- p.47 / Chapter 3.3.2 --- Simulation studies --- p.51 / Chapter 3.3.3 --- Prototype and Experimental results --- p.59 / Chapter 3.3.4 --- Comparison with a reference PIFA --- p.66 / Chapter 3.4 --- Mobile phone installed with the MRIFA --- p.70 / Chapter 3.5 --- Summary --- p.80 / Reference --- p.81 / Chapter Chapter 4 --- A fast method to evaluate Total Isotropic Sensitivity (TIS) in mobile phone active measurement --- p.82 / Chapter 4.1 --- Introduction --- p.82 / Chapter 4.2 --- Proposed fast method for TIS evaluation --- p.85 / Chapter 4.2.1 --- Observed relationship between total Effective Isotropic Radiated Power (EIRP) and total Effective Isotropic Sensitivity (EIS) --- p.85 / Chapter 4.2.2 --- EIS's estimation from EIRPs for TIS evaluation --- p.89 / Chapter 4.3 --- Summary --- p.92 / Reference --- p.93 / Chapter Chapter 5 --- Conclusion --- p.94 / List of Publications --- p.96 / Appendix A - Details of sample mobile phones investigated in this thesis research --- p.97 / Appendix B - Active measurement of mobile phone's transmit power and receiver sensitivity --- p.107 / Appendix C - MRIFA realization procedure --- p.118
103

Physical limitations on antennas

January 1952 (has links)
John Ruze. / "May 27, 1953." / Bibliography: p. 84-85. / Army Signal Corps Contract DA36-039 sc-42607 Project 132B Dept. of the Army Project 3-99-10-022
104

Physical limitations of omnidirectional antennas

January 1948 (has links)
L.J. Chu. / "May 1, 1948." / Includes bibliographical references. / Army Signal Corps Contract No. W-36-039 sc-32037.
105

Contrawound toroidal helical antenna modeling using the FDTD method

ElSherbini, Khaled Mohammad. January 2000 (has links)
Thesis (Ph. D.)--West Virginia University, 2000. / Title from document title page. Document formatted into pages; contains xiii, 325 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 138-144).
106

Slow wave ion heating and parametric instabilities in the HELIX helicon source

Kline, John L. January 2002 (has links)
Thesis (Ph. D.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains viii, 176 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references.
107

Application of genetic algorithms to the design of microstrip antennas, wire antennas and microwave absorbers

Choo, Hosung. January 2003 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2003. / Vita. Includes bibliographical references. Available also from UMI Company.
108

Vulnerability of wireless point-to-point systems to interception /

Lim, Wee Pin Melvin. January 2003 (has links) (PDF)
Thesis (M.S. in Engineering Science (Electrical Engineering))--Naval Postgraduate School, December 2003. / Thesis advisor(s): David C. Jenn, Jeffrey B. Knorr. Includes bibliographical references (p. 73). Also available online.
109

Mobile device antenna design & isolation technologies

Rowell, Corbett Ray. January 2013 (has links)
Mobile device antenna design and isolation technologies are thoroughly investigated in this thesis. The antenna design parameters for mobile devices are quantified using practical restraints by analyzing almost 60 mobile handsets and the effect of materials, human tissue, manufacturing, and antenna type/placement on antenna design and then mapped into Wheeler-space that correlates the spherical wave modes with the antenna performance. The isolation technologies with mutual coupling anti-resonances are unified by a single performance parameter to distinguish them from the more traditional isolation technologies. This unifying performance parameter is the group delay between two antennas where high group delay indicates the presence of a bandstop filter in the form of either a PCB or an antenna modification. This thesis analyzes both PCB and antenna modifications with high group-delay and demonstrates these types of antennas can be placed in close proximity without affecting other performance parameters. It is also shown that both the PCB and antenna modifications contain two isolation methods where each isolation method is a mirror complement of the other method. Some antenna geometries can also increase the mutual coupling in order to improve the antenna performance using a phenomena called over-coupling. These over-coupled antenna systems can result in lower SAR for the cellular antennas and decreased array sizes for NFC/RFID/wireless-power antennas, resulting in better performance of antennas inside mobile devices. / published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy
110

Multiple antenna wireless systems: capacity and user performance limits

Airy, Manish 28 August 2008 (has links)
Not available / text

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