| Large scale proliferation of wireless technology coupled with the increasingly hostile information security landscape is of serious concern. The fundamental broadcast nature of wireless data transmission aggravates the problem, since unlike wired networks, it introduces multiple avenues for attack and penetration into a network. Though several traditional mechanisms do exist to protect wireless networks against threats, vulnerabilities continue to exist, and have been repeatedly demonstrated to be susceptible to failure under different circumstances.;The resulting uncertainties have led to a significant paradigm shift in the design and implementation of wireless security in recent times, among which wireless channel based authentication schemes have shown a lot of promise. Channel based authentication schemes are rooted on the simple fact that a legitimate user and an adversary cannot be physically co-located and hence the underlying multipath structure corresponding to the two links cannot be the same. However most wireless systems are constrained in terms of bandwidth, power and number of transceivers, which seriously limit the performance of such channel based security implementations.;To overcome these limitations, this research proposes a new dimension to the channel based security approach by introducing the capabilities of reconfigurable antennas. The main objective of this work is to demonstrate that the ability of reconfigurable antennas to generate different channel realizations that are uncorrelated between different modes will lead to significant improvements in intrusion detection rates. To this end, two different intrusion detection schemes that exploits the channels generated by a reconfigurable antenna are proposed and evaluated through measurements. To facilitate the analysis of such schemes through simulations, a novel channel modeling approach is also presented. Several reconfigurable antenna designs and a metamaterial based substrate that can help miniaturize such reconfigurable antennas and arrays are also included in this holistic study.;Despite their capability to improve spectral efficiency, the widespread adoption of reconfigurable antennas has been hampered by their complexity, cost and size. The work presented in this thesis is therefore intended to serve as a catalyst to the widespread adoption of reconfigurable antenna technology by adding value to such antennas by utilizing them for enhancing system security and providing a mechanism to miniaturize them to facilitate their integration into modern space constrained wireless devices. |
