Hamid, Mohamad Rijal (2011)
Ph.D. thesis, University of Birmingham.
The work described in this thesis concerns the combining of wideband and reconfigurable narrow band functionality into a single antenna. This concept may be useful in reducing size and to give flexibility to a wireless terminal to operate in several different modes. The approach also offers additional pre-filtering to the front-end, which reduces the interference levels at the receiver, giving them a significant advantage over fixed non reconfigurable transceivers. Wideband-narrowband reconfiguration is potentially useful for future wireless communications such as software defined radio and cognitive radio, since they may employ wideband sensing and reconfigurable narrowband communications. Five novel reconfigurable antennas are presented. One is a switchable log periodic patch array and four are Vivaldi antennas with various forms of reconfiguration. The log periodic is reconfigured by placing switches between the patches and the feed line whilst the Vivaldi antenna has switched resonators controlling the current in the edges of the tapered slots. Wideband to various narrowband functions, wideband with a tunable band rejection having a very wide tuning ratio, and combined three function wide, narrow and tunable band rejection in a single antenna are demonstrated. Prototypes are presented with PIN diode switches, varactors, fixed capacitor or hard wire switches. Measured and simulated results with a very good agreement are presented, thus verifying the proposed concepts.
This unpublished thesis/dissertation is copyright of the author and/or third parties. The intellectual property rights of the author or third parties in respect of this work are as defined by The Copyright Designs and Patents Act 1988 or as modified by any successor legislation. Any use made of information contained in this thesis/dissertation must be in accordance with that legislation and must be properly acknowledged. Further distribution or reproduction in any format is prohibited without the permission of the copyright holder.
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