Global ETD Search

21	Design and Implementation of Radio Frequency Power Feeding Networks for Antenna Array Applications: Simulation and Measurements of Multiport, Equal and Unequal, Fixed and Reconfigurable Radio Frequency Power Feeding Networks for Narrow and Ultra-Wideband Applications Ali, Ammar H.A. January 2018 (has links) Power dividers are vital components and widely used in radio technology, such as antenna arrays, power amplifiers, multiplexers and mixers. A good example is the well-known Wilkinson power divider with its distinctive feeding network characteristics. A comprehensive review indicated that limited research is carried out in the area of planar multiport and reconfigurable power dividers in terms of the power levels between output ports. The main objectives of this work were to develop a small size power divider, a planer multi-output ports power divider and a power divider with a reconfigurable power division ratio. These power dividers were designed to operate over either an ultra-wideband frequency (3.1-10.6 GHz) or WLAN bands (2.4 or 5.2 GHz). A novel multi-layered topology solved the complexity of interconnecting isolation resistors by introducing an additional layer below the ground layer. The prototype was fabricated and tested to validate the results. The measurements and simulation were in good agreement. Finally, a novel uniplanar power divider with reconfigurable output power level difference was developed. The configurability feature was achieved by tuning the quarter wave transformer using one varactor diode. The power divider was applied to improve a full duplex system cancellation performance at the receiver element caused by interference from in-site transmitting antennas. This study investigated fixed power dividers, multi-output power dividers and reconfigurable power dividers. The measurements validated by the simulation results and applications proved the designed power dividers could be used in practical applications. / Higher Committee for Education Development (HCED), Iraq Wilkinson power divider Uniplanar power divider Multi-layer power divider Multi-port power divider Ultra-wideband power divider Reconfigurable power divider Equal and unequal power divider Antenna array Feeding network Quarter-wavelength transformer
22	Realization of Miniaturized Multi-/Wideband Microwave Front-Ends Al Shamaileh, Khair Ayman January 2015 (has links) No description available. Electrical Engineering Electromagnetics Engineering antipodal Vivaldi antenna Bagley power divider broadband Fourier series microstrip lines multi-frequency non-uniform transmisison lines quadrature branch-line coupler ultra-wideband wideband Wilkinson power divider
23	Monarch Cheers, Integration Whimpers, and a Loyalty Conflict: Kansas City Call's Coverage of the Black Yankees, 1937-1955 Eames, Eric M. 05 December 2008 (has links) (PDF) Already regarded as one of the top teams in Negro League baseball, the Kansas City Monarchs became known as a powerhouse unit in the 1930s and 40s. They rolled into towns with lights, amazing athletes, and competitive play. They won championship after championship during these years as Kansas City baseball fans strongly supported them. As they became an integral part of the city, the Monarchs' success, open-seating policy, and jazzy home openers fostered a large following of mixed-race fans. The local black newspaper, the Kansas City Call, held them up on a pedestal, while sportswriters for the mainstream Kansas City Star/Times downplayed the Monarchs' accomplishments and influence in the community. This thesis focuses on the relationship the Call had with the best team in black baseball through the context of its treatment of games, players, league officials, and team owners, as well as other patterns and tactics. Analysis of the Star/Times coverage is also considered to show variances in coverage between one city's race-divided newspapers. Negro League baseball and the African American newspapers that covered the teams grew out of and illustrated the segregation laws and prejudices feelings that existed in the United States during most of the twentieth century. Over time, especially when the sports world moved into the post-integration period, the Call's bolstering of the Monarchs deteriorated as the paper's promotion of democracy steered its sportswriters away from a baseball organization that symbolized segregation. The different types of coverage by the Call throughout the twenty-year study can be described as all-out promotion, balance, and abandonment. In the 1950s nostalgia and conflict existed, as the Call's sportswriters became torn on how to cover a team that was once the pride of the black community, but now represented inequality. In an attempt to remedy this torment, the Call tried to convince black baseball officials to remove the “Negro League” stigma by signing players of all races in order to mirror the more democratic Major Leagues. The white press, meanwhile, ignored the bigger issues of black baseball as one Negro League team after another died in the 1950s. The Star/Times peripheral coverage of the Monarchs provides context to the social issues and discriminatory practices at play in Missouri. As this thesis outlines the coverage of the Monarchs through the Black and White newspapers of Kansas City, previous research is substantiated and challenged to provide a fuller account of Jim Crow's effects. Monarchs Kansas City Negro Leagues black press Jim Crow black baseball Kansas City Call Chester A. Franklin John I. Johnson Chicago Defender Pittsburgh Courier Wendell Smith Sam Lacy Frank Young Lucile Bluford Ernest Mehl C.E. McBride Kansas City Star Kansas City Times white press segregation Major Leagues color barrier baseball integration baseball Buck O'Neil J.L. Wilkinson Tom Baird Satchel Paige Jackie Robinson Hank Thompson Ernie Banks opening day jazz Missiouri Communication

Page generated in 0.0212 seconds