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Joint Time/Frequency Analysis and De...

Elmansouri, Mohamed Ali.

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Joint Time/Frequency Analysis and Design of Spiral Antennas and Arrays for Ultra-Wideband Applications.

紀錄類型:	書目-語言資料,印刷品 : Monograph/item
正題名/作者:	Joint Time/Frequency Analysis and Design of Spiral Antennas and Arrays for Ultra-Wideband Applications./
作者:	Elmansouri, Mohamed Ali.
面頁冊數:	244 p.
附註:	Source: Dissertation Abstracts International, Volume: 74-09(E), Section: B.
Contained By:	Dissertation Abstracts International74-09B(E).
標題:	Physics, Electricity and Magnetism. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3561957
ISBN:	9781303093692

Joint Time/Frequency Analysis and Design of Spiral Antennas and Arrays for Ultra-Wideband Applications.
Elmansouri, Mohamed Ali.

Joint Time/Frequency Analysis and Design of Spiral Antennas and Arrays for Ultra-Wideband Applications. - 244 p.

Source: Dissertation Abstracts International, Volume: 74-09(E), Section: B.

Thesis (Ph.D.)--University of Colorado at Boulder, 2013.

Ultra-wideband (UWB) systems transmit and receive extremely short pulses, permitting the corresponding antennas to distort their shape. Thus the design of an antenna for a UWB system plays an important role for the reliability and quality of communication. A UWB antenna design coalesces both the determination of conventional frequency domain parameters and the analysis of time domain response into a single overarching system requirement. While the former is needed to ensure system's sensitivity, the later is critical to minimize pulse distortion.

ISBN: 9781303093692Subjects--Topical Terms:

1019535
Physics, Electricity and Magnetism.

Joint Time/Frequency Analysis and Design of Spiral Antennas and Arrays for Ultra-Wideband Applications.
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100 1 $a Elmansouri, Mohamed Ali. $3 2101195
245 1 0 $a Joint Time/Frequency Analysis and Design of Spiral Antennas and Arrays for Ultra-Wideband Applications.
300 $a 244 p.
500 $a Source: Dissertation Abstracts International, Volume: 74-09(E), Section: B.
500 $a Adviser: Dejan S. Filipovic.
502 $a Thesis (Ph.D.)--University of Colorado at Boulder, 2013.
520 $a Ultra-wideband (UWB) systems transmit and receive extremely short pulses, permitting the corresponding antennas to distort their shape. Thus the design of an antenna for a UWB system plays an important role for the reliability and quality of communication. A UWB antenna design coalesces both the determination of conventional frequency domain parameters and the analysis of time domain response into a single overarching system requirement. While the former is needed to ensure system's sensitivity, the later is critical to minimize pulse distortion.
520 $a Well-designed spiral antennas are known for their almost frequency independent characteristics; thus they are viable candidates for UWB systems from the frequency-domain side. However, due to their fundamental principles of operation, they are dispersive and arguments were made they should not be used for pulsed UWB applications (time-domain side). The presented research unequivocally proves that spiral antennas and various derivatives thereof, including arrays, can be excellent candidates for multi-functional time/frequency domain systems.
520 $a A complete framework for joint frequency and time domain characterization of planar spiral antennas in UWB communication systems is developed first. By utilizing theory, simulations, and experiments, all essential to the analysis frameworks, the various hypotheses are comprehensively treated and relevant conclusions are established. The dispersion and pulse distortion of the conventional spiral antennas are characterized in the radiation and system modes and conclusions regarding the effects of geometrical parameters such as number of arms, mode of operations, etc., on time- and frequency-domain performance are derived for the first time. A method based on controlling the spiral's growth rate and input pulse shape is demonstrated as an effective approach to reduce the pulse distortion. Theoretical pre-distortion compensation method based on a frequency-dependent delay removal technique is employed and performance enhancement of spiral antennas as pulse radiators is successfully demonstrated. A novel spiral antenna topology, named combined power spiral, is derived from first principles to have simultaneously excellent time- and frequency-domain performances without any auxiliary hardware and/or pre-distortion compensation. The role of the reflective cavity backing on the performance of spiral antennas in time and frequency domains is investigated in order to achieve an efficient unidirectional UWB radiation. Resistively-loaded cavity-backed spirals are designed as a compromise for achieving simultaneously good time and frequency domain performances while maintaining high efficiency over the most of operating bandwidth. The lens loading approach is used as a way to further improve the spiral's gain and reduce the amplitude distortion associated with a typical communication channel. UWB spiral arrays based on the derived good time/frequency two- and four-arm spiral antennas are developed and analyzed in time and frequency domains. Multi-mode capabilities of four-arm spirals are used to engineer a dual-circularly polarized array embodiment. To make these arrays practically more desirable, novel feeding scheme which significantly reduces the beamformer complexity is proposed. Time and frequency scanning capabilities and the advantages of the proposed arrays for UWB communications are also discussed. The results of this thesis can pave the way for the use of spiral antennas in many non-traditional, for spiral antennas, applications across commercial and military sectors.
590 $a School code: 0051.
650 4 $a Physics, Electricity and Magnetism. $3 1019535
650 4 $a Engineering, Electronics and Electrical. $3 626636
690 $a 0607
690 $a 0544
710 2 $a University of Colorado at Boulder. $b Electrical Engineering. $3 1025672
773 0 $t Dissertation Abstracts International $g 74-09B(E).
790 $a 0051
791 $a Ph.D.
792 $a 2013
793 $a English
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3561957