This thesis studies a new class of high gain planar resonant cavity antennas based on
metamaterial surfaces. High-gain planar antennas are becoming increasing popular
due to their significant advantages (e.g. low profile, small weight and low cost).
Metamaterial surfaces have emerged over the last few years as artificial structures that
provide properties and functionalities not readily available from existing materials.
This project addresses novel applications of innovative metamaterial surfaces on the
design of high-gain planar antennas.
A ray analysis is initially employed in order to describe the beamfonning action of
planar resonant cavity antennas. The phase equations of resonance predict the
possibility of low-profile/subwavelength resonant cavity antennas and tilted beams.
The reduction of the resonant cavity profile can be obtained by virtue of novel
metamaterial ground planes. Furthermore, the EBG property of metamaterial ground
planes would suppress the surface waves and obtain lower backlobes. By suppressing
the TEM mode in a resonant cavity, a novel aperture-type EBG Partially Reflective
Surface (PRS) is utilized to get low sidelobes in both planes (E-plane and H-plane) in
a relatively finite structure. The periodicity optimization of PRS to obtain a higher
maximum directivity is also investigated. Also it is shown that antennas with unique
tilted beams are achieved without complex feeding mechanism. Rectangular patch
antennas and dipole antennas are employed as excitations of resonant cavity antennas
throughout the project. Three commercial electromagnetic simulation packages
(Flomerics Microstripes ™ ver6.S, Ansoft HFSSTM ver9.2 and Designer ™ ver2.0)
are utilized during the rigorous numerical computation. Related measurements are
presented to validate the analysis and simulations.
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.