Engineering Commons^™

Dual-Band Non-Stationary Channel Modeling For The Air-Ground Channel, Ruoyu Sun

Theses and Dissertations

Multiple air-to-ground (AG) radio propagation channels are experimentally characterized for two frequency bands, C-band and L-band. These characterizations are aimed to support the specification of the control and non-payload communication (CNPC) links being designed for civil unmanned aircraft systems (UAS). The use of UAS is expected to grow dramatically in the coming decades. In the United States, UAS will be monitored and guided in their operation within the national airspace system (NAS) via the CNPC link. The specifications of the CNPC link are being designed by government, industries, academia and standards bodies such as the Radio Technical Commission for Aeronautics …

Technology Development And Characterization Of Aiinn/Gan Hemts For High Power Application, Mahbuba Sultana

Theses and Dissertations

AlInN has attracted much attention only recently as a material due to its unique and superior material properties, which is however known to be difficult to be grown among the III-nitride ternary compounds. The electrons confined at the heterointerface of coherently grown AlInN on GaN buffer layers determine crucial electronic properties. This dissertation has been designed targeting the lattice matched AlInN/GaN investigation with very detail to optimize the design, fabrication process, and electronic properties to realize AlInN/GaN HEMTs. Each single step of this process was optimized in order to improve device performance.

The work started with establishing the main features …

Investigation Of Modular Multilevel Converter Performance Under Non-Ideal Distribution System Conditions, Rostan Rodrigues

Theses and Dissertations

The Modular Multilevel Converter (MMC) is an emerging power converter technology that has caught widespread attention mainly because of several technical and economic benefits such as modular realization, easy scalability, low total harmonic distortion, fail-safe operations etc. The MMC is comprised of a series connection of sub-modules (SM). A sub-module is made by either a half-bridge or a full-bridge IGBT device and a capacitor as a source of energy connected across the bridge. This modular structure allows for the possibility to design high-voltage converters handling hundreds of kilo-volts without direct series connection of the power semiconductor devices.

Due to its …

Iii-V Nitride Based Microcantilever Heaters For Unique Multimodal Detection Of Volatile Organic Compounds At Low Temperature, Ifat Jahangir

Theses and Dissertations

Detection of volatile organic compounds (VOCs), which are widely used in industrial processes and household products, is very important due to significant health hazards associated with them. VOCs are commonly detected using photo-ionization detectors (PIDs), suspended hot bead pellistors, or heated metal oxide semiconductor functionalization layers. However, these techniques used for detecting VOCs often suffer from one or more of the following issues - high power consumption, limited selectivity, complicated functionalization technique and expensive characterization tools. On the other hand, microcantilevers offer excellent avenues for molecular sensing that arises out of their high sensitivity to various physical parameter changes induced …

Fabrication And Characterization Of Graphene Based Biocompatible Ion-Sensitive Field Effect Transistor (Isfet), Rina Patel

Theses and Dissertations

Graphene, a two-dimensional material with a high surface to volume ratio, has drawn extensive research enthusiasm for applications in the field of electronic sensors. The special material properties that make graphene a highly promising material include its biocompatibility, very high mobility, low 1/f and thermal noise, modulation of carrier concentration and fermi level by electrical, optical, and chemical means. To exploit these properties for practical applications a large area high quality graphene, transferred on appropriate substrates, is required. In this work, high quality single monolayer graphene (determined from Raman spectroscopy) has been synthesized by chemical vapor deposition (CVD) technique for …

Inn Nems And Heterojunction Devices For Sensing Applications, Alina Wilson

Theses and Dissertations

Recent research trends in chemical and biological sensing have been geared toward developing molecular sensor devices that are fast, inexpensive, miniaturized, have low power consumption and are portable. The performance of these devices can be dramatically improved by utilizing multimodal detection techniques, new materials and nanofabrication technologies. To develop such sensor devices, we utilized Indium Nitride (InN) nanowires (NWs) to fabricate nanoelectromechanical system (NEMS) based sensors and Graphene/InN NW heterojunctions, and InN thin films to fabricate Graphene/InN thin film heterojunction based sensors. InN NWs, which exhibit interesting properties including high carrier density, superior electron mobility, strong surface charge accumulation, and …