Dynamic Capacity Enhancement using a Smart Antenna in Mobile Telecommunications Networks

This work describes an investigation into the performance of antennas for mobile base station applications and techniques for improving the coverage and capacity within a base station cell. The work starts by tracing the development of mobile systems, both in technical and commercial terms, from the earliest analogue systems to present day broadband systems and includes anticipated future developments. This is followed by an outline of how smart antenna systems can be utilised to improve cell coverage and capacity. A novel smart antenna system incorporating an array of slant ± 450 dual- polarised stacked patch elements four columns wide excited by a novel multi-beam forming and beam shaping network has been designed, simulated and implemented. It is found that for an ideal smart antenna array, four narrow overlapping beams, one wide “broadcast channel” beam and right and left shaped beams can be provided. Results are presented for the simulation of the smart antenna system using CST EM simulation software which inherently includes mutual coupling and the effects of a truncated ground plane on the element patterns. The results show some significant changes to the desired set of coverage patterns and various mutual coupling compensation techniques have been reviewed. An improved design technique has been developed for compensating the performance degrading effects of mutual coupling and finite ground plane dimensions in microstrip antenna arrays. The improved technique utilises combination of two previously known techniques: complex excitation weights compensation by inversion of the array mutual coupling scattering matrix and the incorporation of a WAIM (wide angle impedance matching) sheet. The technique has been applied to a novel multi-beam smart antenna array to demonstrate the efficacy of the technique by electromagnetic simulation. In addition, a demonstrator array has been constructed and tested which has yielded a positive conformation of the simulation results. For the developed demonstrator array which provides seven different beams, beams “footprints” have been predicted both for free space propagation and for urban propagation to evaluate the dynamic capacity performance of the smart antenna in a 3G mobile network. The results indicate that sector capacity can be dynamically tailored to user demand profiles by selection of the appropriate beam patterns provided by the novel smart antenna system

Dynamic capacity enhancement using a smart antenna in mobile telecommunications networks

This work describes an investigation into the performance of antennas for mobile base station applications and techniques for improving the coverage and capacity within a base station cell. The work starts by tracing the development of mobile systems, both in technical and commercial terms, from the earliest analogue systems to present day broadband systems and includes anticipated future developments. This is followed by an outline of how smart antenna systems can be utilised to improve cell coverage and capacity. A novel smart antenna system incorporating an array of slant ± 450 dual- polarised stacked patch elements four columns wide excited by a novel multi-beam forming and beam shaping network has been designed, simulated and implemented. It is found that for an ideal smart antenna array, four narrow overlapping beams, one wide “broadcast channel” beam and right and left shaped beams can be provided. Results are presented for the simulation of the smart antenna system using CST EM simulation software which inherently includes mutual coupling and the effects of a truncated ground plane on the element patterns. The results show some significant changes to the desired set of coverage patterns and various mutual coupling compensation techniques have been reviewed. An improved design technique has been developed for compensating the performance degrading effects of mutual coupling and finite ground plane dimensions in microstrip antenna arrays. The improved technique utilises combination of two previously known techniques: complex excitation weights compensation by inversion of the array mutual coupling scattering matrix and the incorporation of a WAIM (wide angle impedance matching) sheet. The technique has been applied to a novel multi-beam smart antenna array to demonstrate the efficacy of the technique by electromagnetic simulation. In addition, a demonstrator array has been constructed and tested which has yielded a positive conformation of the simulation results. For the developed demonstrator array which provides seven different beams, beams “footprints” have been predicted both for free space propagation and for urban propagation to evaluate the dynamic capacity performance of the smart antenna in a 3G mobile network. The results indicate that sector capacity can be dynamically tailored to user demand profiles by selection of the appropriate beam patterns provided by the novel smart antenna system.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

The effects of a finite ground plane on the characteristics of printed patch antennas with and without a suspended patch

In most analyses of microstrip patch antennas the effects of a finite ground plane are neglected because it is assumed infinite. However, in mobile communication systems the ground plane of antennas must be finite. Therefore, the effect of the finite ground plane on the characteristics of printed patch antenna elements is worth investigation. In this paper a stacked patch antenna has been proposed and the effects of a finite ground plane on the total radiation pattern are investigated. In fact, we have shown that a truncated ground plane of width approximately one wavelength will produce a 3dB beam width for the patch of approximately 65 degrees in contrast to the 90 degrees which occurs for an infinite ground plane. A physical description of the reason for this is included

Modelling and analysis of a smart antenna system with sub-sector dynamic capacity enhancement for mobile telecommunication networks

This paper describes the modelling and analysis of a new smart antenna concept. The paper outlines the rational for the development of a dynamically reconfigurable smart antenna system without greatly increasing the complexity of the system. The subject smart antenna system is developed to offer good coverage and capacity using multiple beams throughout a cell sector and to be able to reconfigure the beam to provide enhanced coverage and maintain capacity in certain areas at reduced, but acceptable coverage throughout the rest of the cell sector of a mobile telecommunication network. The motivation behind the architecture and the methodology used is discussed and then modelling and analysis of the antenna system is presented

Design of a highly efficient beam scanning asymmetric H-plane horn antenna

This paper presents the design and results of a novel asymmetric H-plane horn antenna with an easily scanable, highly efficient asymmetric radiation pattern. This design offers a cost-effective and practical alternative to the current beam scanning horn antennas used in surveillance radars in which bulky and expensive switching and phase shifting circuits and time consuming rotation mechanisms are used for these antennas to feed the parabolic reflectors asymmetrically to improve the air and coastal scanning performance. In order to achieve that, the flares of the proposed asymmetric H-plane horn antenna, which is constructed from aluminum, are adjusted in a different way from the traditional horn antennas so that it is possible to shift the main lobe in a desired direction by setting the flare angle s differently. The near and far-field measurement results, which are in a good agreement with the simulation results, demonstrate the beam scanning performance of the proposed antenna through the use of adjustable asymmetric flares throughout the paper

A solar parabolic reflector antenna design for digital satellite communication systems

This paper introduces a compact solar parabolic reflector antenna design, with an effective DC solar performance and high gain / pencil beam antenna radiation characteristics, as an alternative to the standalone use of home-based autonomous solar panels and digital satellite antennas. The proposed solar reflector antenna consists of 2 parabolic shaped silicon solar panels with a diameter of 60 cm, each constructed by connecting individual silicon solar cells electrically in appropriate angles in order to create an approximate parabolic surface. The solar panels within the design have been connected in parallel in order to increase the total DC output level for medium and high current appliances. The bottom DC contact layer of the first silicon solar panel, which collects the DC current generated by the electrically connected solar cells within the panel as a result of the photovoltaic effect, also works as a parabolic reflector antenna with an average gain of 32.8 dB at the digital satellite downlink frequency band of 10.70 - 12.75 GHz, allocated by the ITU to the Region 1, including Europe