Engineering Commons^™

Electrical And Optical Properties Of Carbon Nanotube Intra-Connects And Conductive Polymers, Seon Woo Lee

Dissertations

Growth of individual carbon nanotube (CNT) intra-connects (bridges) between two prefabricated electrodes is a great challenge and a pre-requisite to the development of single electron devices. In this thesis, CNT intra-connects were fabricated and studied. Later on, the intra-connects were deposited with electrically conductive polymer (ECP) in the realization of CNT/ECP hybrids.

The process started by realizing two electrodes with sharp end on a silicon wafer using e-beam lithography. The intra-connects were then grown by use of chemical vapor deposition (CVD) technique. The intra-connects were later electroplated by various conductive polymers. The morphology, electrical conductivity of these intra-connects as well …

Practical Localized Waves Generation, Mohamed Ahmed Salem

Dissertations

Since the early works on localized waves (LW), extensive results were published on this important subject, from both the theoretical and the experimental points of view. Nevertheless, those experimental techniques of LW generation suffer from several shortcomings. A major one is that only pulse peaks were accredited. Either the full profile of the generated pulse was not reported, or it was not closely matching the theoretical profile. Additionally, low resolutions of the generated LWs were reported in the acoustic X-Waves. The conductors of the experiment attributed this effect to the limited bandwidth of the excitation elements.

The interest in the …

Non-Foster Matching Of An Rfid Antenna, Nedime Pelin Yalcin

Theses

In this thesis, novel designs of radio-frequency identification (RFID) tag antennas with better matching characteristics to achieve extended range for passive tags have been investigated in the ultra-high frequency (UHF) band. A variety of cavitybacked/coupled microstrip dipole antennas in 915 MHz range were considered. Additionally, a negative impedance converter designed to cancel out antenna's input capacitance at resonance frequency and to produce the real antenna input impedance was designed, simulated and implemented for an RFID antenna. Numerical simulations have been carried out using ORCAD software package (Cadence), ADS software package (Agilent) and HFSS software package (ANSYS/ANSOFT Inc). Antennas have been …

I/Q Imbalance Mitigation For Space-Time Block Coded Communication Systems, Mingzheng Cao

Dissertations

Multiple-input multiple-output (MIMO) space-time block coded (STBC) wireless communication systems provide reliable data transmissions by exploiting the spatial diversity in fading channels. However, due to component imperfections, the in-phase/quadrature (I/Q) imbalance caused by the non-ideal matching between the relative amplitudes and phases of the I and Q branches always exists in the practical implementation of MIMO STBC communication systems. Such distortion results in a complex conjugate term of the intended signal in the time domain, hence a mirror-image term in the frequency domain, in the data structure. Consequently, I/Q imbalance increases the symbol error rate (SER) drastically in MIMO STBC …

Clustered Wireless Sensor Networks, Renita Margaret Machado

Dissertations

The study of topology in randomly deployed wireless sensor networks (WSNs) is important in addressing the fundamental issue of stochastic coverage resulting from randomness in the deployment procedure and power management algorithms. This dissertation defines and studies clustered WSNs, WSNs whose topology due to the deployment procedure and the application requirements results in the phenomenon of clustering or clumping of nodes. The first part of this dissertation analyzes a range of topologies of clustered WSNs and their impact on the primary sensing objectives of coverage and connectivity. By exploiting the inherent advantages of clustered topologies of nodes, this dissertation presents …

A Novel Storage Area Network (San) Extension Solution Over Passive Optical Networks (Pons), Si Yin

Dissertations

After 9/11 and the 2003 power grid failure in North America, storage area network (SAN) extension has emerged as a critical option to ensure business continuity. However, SAN extension encounters challenges in the access network including the scalability, cost, bandwidth bottleneck, and throughput. In this dissertation, a new solution, SAN extension over passive optical networks (S-PONs), has been proposed to address the above problems. PONs are the mainstream wireline technology for upgrading the megabit-level access solutions (such as xDSL and Cable Modem) into gigabit-level broadband access. To tackle the scalability problem and cost challenge, the S-PON architecture has been designed …

Nano-Structured Platforms As A Spectroscopic Tool, Ruiqiong Li

Theses

Nano-structured platforms have been studied for the purpose of enhancing weak fluorescence signals. Each platform was constructed as a thin oxide layer on top of a metal (aluminum) The oxide was perforated with hexagonal array of nano-holes. The pitch of the array was much smaller than the optical wavelengths used. Surface charge waves (Surface Plasmons) could be excited when the platform was oriented at specific direction with respect to the incident optical beam. At this point one can demonstrate that fluorescence signals could be amplified. Since the oxide (alumina) is bio-compatible, one can envision using such platforms in the study …