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Title: Investigation of antenna and propagation solutions to enhance system efficiency for green mobile communications
Author: Li, Lingjian
Awarding Body: University of Bristol
Current Institution: University of Bristol
Date of Award: 2013
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As part of the general study within the Mobile VCE 'Green Radio' project, this research work was driven by the goal of facilitating the power consumption reduction in mobile wireless networks to decrease the carbon emission and costs for mobile operators. This thesis gives an analysis of the RP signal from transmit antenna to receive antenna in terms of efficiency, with main emphasis on the base station. The design of high efficiency antennas and arrays for base station usage was discussed and a Suspended Plate Antenna (SPA) implementing air as the 'substrate' was presented as the 'best case' benchmark for BS antenna efficiency evaluation. Full three-dimensional far-field radiation patterns and other antennas parameters were analysed using Finite Difference Time Domain modelling and thoroughly measured. Uncertainties in the efficiency measurements have been determined to lay between ± 5% and ± 7% depending on the measurement technique employed. The impact of dielectric loss on antenna radiation efficiency was investigated through practical measurement of patch antennas with typical dielectric substrates in the 2 and 5 GHz bands. The results showed that by using cheap but lossy materials 3-5 dB and 2-3 dB power could be 'thrown away' in the 2 and 5 GHz band respectively, compared to the use of more expensive materials. This work has also considered a method to enhance the bandwidth of the SPA whilst maintaining high efficiency. The new antenna feed produced a significantly improved input bandwidth and can fully meet the 250 MHz (1920-2170 MHz) requirement for 3G LTE operation with over 90% radiation efficiency across the whole band. Finally, this thesis discusses the methodology of evaluating BS antenna performance in propagation environment. A Line of Sight (LoS) propagation modelling tool was designed that includes the full radiation pattern information (magnitude, phase and polarisation) for both transmit and receive antennas. Studies of BS downtilt and user antenna orientations showed that full pattern characteristics and polarisation information are essential for evaluating antenna performance in LoS scenarios.
Supervisor: Hilton, Geoffery ; Paul, Dominique Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available