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Multiband Coupled-Fed Monopole Antennas for Mobile Communication DevicesChang, Chih-Hua 25 October 2010 (has links)
In this dissertation, a variety of multiband communication device antennas using the coupling-feed mechanism are presented. The coupling feed contributes additional capacitance to the antenna¡¦s input impedance which shows a high inductive component for the traditional case of using a direct feed. In the first and second antenna designs, with the coupling feed, the high input inductance of the antenna is effectively compensated. This behavior leads to a dual-resonance excitation for the lower band of the antenna. Two wide operating bands are achieved, allowing the antenna¡¦s lower and upper bands to easily cover GSM850/900 and GSM1800/1900/UMTS operation. For the last two antenna designs, owing to the coupling feed, the very large input impedance seen at antenna¡¦s lower band is greatly decreased and results in successful excitation of the one-eighth wavelength (£f/8) mode of the antenna. The specific absorption rate and hearing aid compatibility results for these mobile phone antennas are also analyzed. The effects of presence of the user¡¦s hand on the laptop computer antenna performance are also studied in this dissertation.
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