THESIS
2021
1 online resource (xv, 134 pages) : illustrations (chiefly color)
Abstract
Antenna design optimization using full EM simulation is computationally expensive and
does not include conventional design techniques or the working mechanism of antenna design.
In order to design antennas in a smarter way, design techniques need to be incorporated into
parameter optimization. One of the important ways to achieve this is to pixelate the metal
on the designed surface.
For the first research contribution, we incorporate N-port Characteristic Mode Analysis
(CMA) into the formulation to obtain an objective function that characterizes the fundamental resonances of the pixel antenna. These fundamental resonant properties of the pixel
antenna are found without requiring the selection of the feeding ports and therefore our
method can provide optimization with better antenna pe...[
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Antenna design optimization using full EM simulation is computationally expensive and
does not include conventional design techniques or the working mechanism of antenna design.
In order to design antennas in a smarter way, design techniques need to be incorporated into
parameter optimization. One of the important ways to achieve this is to pixelate the metal
on the designed surface.
For the first research contribution, we incorporate N-port Characteristic Mode Analysis
(CMA) into the formulation to obtain an objective function that characterizes the fundamental resonances of the pixel antenna. These fundamental resonant properties of the pixel
antenna are found without requiring the selection of the feeding ports and therefore our
method can provide optimization with better antenna performance without needing to optimize the feed positions simultaneously.
For the second contribution feeding port optimization is proposed by using sequential
feeding port selection. This can greatly reduce the search space and computational load. In addition, this approach does not require additional complex feeding networks or impedance
matching circuits. This makes the design simple, compact and practical.
For the third contribution, perturbation sensitivity is used to assist the optimization of
pixel antennas, making it possible to use gradient based optimization algorithms. Specific algebraic techniques are used to calculate the perturbation sensitivity of each port, which
avoids the inversion of impedance matrices at each evaluation of the objective function. This significantly reduces the computational load and results demonstrate better optimization
performance compared to GA and SEBO.
For the fourth contribution, space mapping (SM) is utilized to optimize multiple-input and
multiple-output (MIMO) antennas. SM is formulated for the optimization of MIMO antennas
and the scope of the coarse models is also expanded to include radiation efficiency. We
extend parameter extraction (PE), to MIMO antennas, and also extend the IMPM approach
to continuous tunable loads to optimize the isolation of external ports using SM.
Throughout the thesis presentation, experimental results are provided to demonstrate the
improvements that the new algorithms and techniques, developed during the thesis, provide.
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