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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.
31

Compact WiMAX Antennas for the Mobile Phone

Lai, Peng-yu 09 June 2008 (has links)
Novel compact antenna designs for WiMAX (Worldwide interoperability for microwave access) operation in the mobile phone are presented in this thesis. In the first design, the antenna is integrated at one corner of system circuit board of the mobile phone and consists of two radiating portions; the monopole slot is formed by integrating the two portions. In the second design, two different antenna structures are used to achieve all WiMAX operating bands. Finally, in the third design, the chip antenna comprises a resonant monopole patch, a resonant shorter slot and a matching longer slot. The latter two slots are embedded within the monopole patch to achieve a compact integration. Detailed antenna designs and experimental results are presented and discussed.
32

Slot allocation in the United States and Europe

Moessner, Philipp. January 2005 (has links)
The following thesis describes and analyzes the development of the U.S. slot allocation system from 1968 until today, in order to draw relevant conclusions for a new European Slot Regulation. The European Commission is currently drafting a new Slot Regulation purporting to introduce market mechanisms. A similar approach was espoused in the United States from 1986 onward, but was ultimately supplanted by overriding legislation in 2000. The analysis of the U.S. slot allocation system reveals the reasons underlying its abolition and queries whether this experience can be successfully transposed in Europe. The thesis commences by providing general information on the definition of slots, slot allocation, and airport capacity. A brief review of the European Commission's current consultation process on the implementation of market mechanisms for slot allocation follows. The main part of the thesis discusses the U.S. High Density Rule and the Rules for the Allocation and Transfer of High Density Airport Slots in historical order. Some criticisms frequently voiced assert that the Rules artificially limited access to airports, constituted barriers to market entry, restricted airline competition, generated higher fares, and yielded adverse effects on smaller communities which, in turn, lost access to key markets. Through a favorable assessment of the Rules, the thesis analyses these concerns and concludes that the suppression of the Rules was rather prompted by local political motivations than by other rationalities. However, experiences drawn from the U.S. Rules demonstrate that a future European secondary market for slots, if implemented under a grand fathering system, will likely have a positive impact on the efficiency of airport capacity, but not on access to the market and competition.
33

Slot allocation in the United States and Europe

Moessner, Philipp. January 2005 (has links)
No description available.
34

Two Elements Elliptical Slot CDRA Array with Corporate Feeding For X-Band Applications

Abdullah, Abdulkareem S., Majeed, Asmaa H., Sayidmarie, Khalil H., Abd-Alhameed, Raed 04 1900 (has links)
Yes / In this paper, a compact two-element cylindrical dielectric resonator antenna (CDRA) array with corporate feeding is proposed for X-band applications. The dielectric resonator antenna (DRA) array is excited by a microstrip feeder using an efficient aperture-coupled method. The designed array antenna is analyzed using a CST microwave studio. The fabricated sample of the proposed CDRA antenna array showed bandwidth extending from 10.42GHz to 12.84GHz (20.8%). The achieved array gain has a maximum of 9.29dBi at frequency of 10.7GHz. This is about 2.06dBi enhancement of the gain in comparison with a single pellet CDRA. The size of the whole antenna structure is about 50 x 50mm2.
35

L-Band Coplanar Slot Loop Antenna for iNET Applications

Nithianandam, Jeyasingh 10 1900 (has links)
ITC/USA 2010 Conference Proceedings / The Forty-Sixth Annual International Telemetering Conference and Technical Exhibition / October 25-28, 2010 / Town and Country Resort & Convention Center, San Diego, California / In this article we present a design of an L-band slot loop antenna with a dielectric loaded conductor backed coplanar waveguide (CBCPW) feed. The coplanar slot loop antenna has a transmission line resonator in series. We used full wave electromagnetic simulations with Ansoft's high frequency structure simulator (HFSS) software in the design of the coplanar slot loop antenna. The series transmission line resonator helps to tune the coplanar slot loop antenna and reduce its size. We present here results on return loss and radiations patterns of coplanar slot loop antenna obtained from HFSS simulations.
36

Design and Development of a Thin Conformal C-Band Telemetry Antenna for a Small Diameter Missile

Cirineo, Tony, Davis, Rick, Byrd, Marvin, Kujiraoka, Scott 10 1900 (has links)
ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, Nevada / This paper will present the preliminary design of a C-Band telemetry antenna mounted conformal to a small diameter missile. Various design studies and options will be explored leading to a preliminary design that best meets system requirements. Simulation results are presented for various options and the rationale for down selection to final configuration is discussed.
37

On-chip photonic crystal waveguide for chemical and biological sensing

Lai, Weicheng 21 November 2014 (has links)
Photonic crystal waveguide (PCW) based device has been used in many applications in recent years due to its unique slow light effect. In this work, the application of PCW on sensing is presented. First, we present a PCW structure based Infrared (IR) spectroscopy combining with slot structure which has a large electric field enhancement for light-matter interaction for chemical sensing. The slow light effect and the electric field enhancement of our designed structure greatly enhance the absorption factor of chemical analytes by 1000. We then use multimode interference (MMI) optical splitter and Y junction combiner to connect two PCWs to show multiplexed detections of two chemicals on a single chip. Our results show the detection is down to 1 ppb for xylene in water and 100ppm for methane in nitrogen. We also present PCW microcavities structure for biological sensing in our work. Due to its high quality factor and easier immobilization of biomaterials, we are able to use ink jet printing method to bind the biomaterials on top of our chip. We choose linear-type 13 (L13, missing 13 holes) microcavities to do the biosensing for antibodies and cancer cell lysates because of its higher sensitivity combining with slow light effect. Our work achieves the cancer cell lysates detection down to 2 cells/μl., and further applications will be presented in our group in the future. / text
38

Design of an 8x8 cross-configuration Butler matrix with interchangeable 1D and 2D arrays

Bartlett, Chad 23 July 2019 (has links)
An ever-increasing demand for wider bandwidths in communication, radar, and imaging systems has emerged. In order to facilitate this growing demand, progressive research into millimeter-wave technologies has become vital in achieving next generation networks such as 5G. Being cost effective and easy to manufacture, Substrate Integrated Waveguide (SIW) circuits have been demonstrated as a viable candidate for high-frequency applications due to their low-loss, high quality-factor, and high power-handling capabilities.Research on beam-forming networks, specifically the Butler matrix, has demonstrated powerful beam-steering capabilities through the use of passive component networks. Through these clever configurations, a cost effective and robust option is available for us to use. In order to further millimeter-wave research in this area, this thesis presents a modified configuration of the Butler Matrix in SIW that is physically reconfigurable; by separating the Butler matrix from the antenna array at a pre-selected point, the array can be easily interchanged with other 1-Dimensional,and 2-Dimensional slot antenna arrays. Although this system does not fall under the rigorous definitions of Reconfigurable Antennas, it should be noted that the interchangeability of 1 and 2 dimensional arrays is not typically expressed in Butler matrix configurations. Design and simulations are carried out in CST Microwave Studio to inspect individual components as well as system characteristics. Circuit prototypes are then manufactured and tested in an anechoic chamber to validate simulation results and the design approach. / Graduate / 2020-07-17
39

GPS based Vehicle Conflict Measurement and Dynamic Slot Allocation

Khan, Eraj, Hayat, Khizar January 2007 (has links)
<p>Our main objective of this thesis is to measure the conflict risk and then on the basis of this risk allocate the slots for future communication.</p>
40

GPS based Vehicle Conflict Measurement and Dynamic Slot Allocation

Khan, Eraj, Hayat, Khizar January 2007 (has links)
Our main objective of this thesis is to measure the conflict risk and then on the basis of this risk allocate the slots for future communication.

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