Miniature antennas for mobile wireless communications

• Main Author: Zuazola, Garcia
• Published: University of Kent 2010
• Subjects: 621.384135
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.591097

The subject of this this has been to produce new antermas suitable for use in Radio-over- Fibre Remote Antenna Units or in Mobile Equi pment which might be used at the other end of the link. Several new antennas have been developed and assessed for their suitable application to RoF systems. The antennas were: (i) a multiband PIFA developed previously in the ROSETTE project and modified here to exhibit an improved match when integrated with a ground plane for ceiling mounting. (ii) A cost effective microstrip array directive antenna for street illumination in the Manhattan Scenario. Beam coverage was controlled by electronic shaping and mechanical tilting. (iii) A new compact PIFA design for use in mobile equipment or sectorized base stations where a slotted structure is used to achieve a sharp edge defined operating bandwidth which allows the antenna to act as a filter, thus reducing component count and insertion loss in the transceiver front end. The antenna has been integrated with a larger handset sized ground plane and its insensitivity to this mounting has been demonstrated. (iv) the antenna in (iii) has been implemented in a 3 sector cluster and interference between sector beams by pattern overlap has been characterized. (v) A new compact PIFA working in the 3-5GHz sub-bands of the FCC UWB band has been described and demonstrated to offer useful performance and exhi bit a useful band pass fil tering characteristic reducing the need for a frontend filter in UW8 systems. (vi) A size reduced PIFA has been presented and studied where the rear ground plane was replaced by a strip element FSS tuned to 450Hz. This was demonstrated to improve performance at that band and the antenna was shown to offer a gain that compared well to a standard PlFA between I and 100Hz. The work described has been undertaken over 3 EU funded projects and the thesis begins with a brief overview of the relevant parts of those projects, particularly how antenna match is of importance at the Remote Antenna Unit of a Radio-over-Fibre system as poor input isolation and reflection can cause ringing in the bidirectional amplifiers associated with the duplex transmission. The new antennas developed for application in mobile equipment are shown to be compact (in relation to electrical size) and are considered in terms of their input bandwidth and efficiency.