Developments on EM wave characteristics control techniques
The projects covered by this research area are as follows:
P1. Active and Patterned EM Structures
TL@NUS has developed a CEM tool for the efficient analysis of frequency selective surfaces (FSS) with multiple periodic arrays of thin-wire elements using vector spectral-domain method with good accuracy. To handle more complex FSS structures, a pattern bank containing 22 1-D or 2-D array patterns has been constructed. Included patterns are monopole (dipole), triangular loop, rectangular loop, hexagonal loop, tripole loop, cross loop, single spiral, double spiral, four-arm spiral, cross, square spiral, tripole, Jerusalem cross, anchor, double square, grid, gridded square, gridded double square, and rectangular patch as well as arbitrary thin-wire pattern.
Differential evolution (DE) method is a special optimization technique with the invention of differential mutation to produce global solution using fewer control parameters. TL@NUS has developed a DE optimizer with high efficiency and robustness. It has been successfully applied to the studies of EM inverse scattering problems, composite materials, and EM structures. Recently, a new differential mutation scheme, the best of random differential mutation, has been developed for achieving well balanced reliability and efficiency. It has also been successfully applied to synthesize antenna arrays.
P2. Electromagnetic Reflector and Advance Techniques on Surface Waves and Polarization
The objective of this project is to develop EM wave characteristics control techniques and associated analysis/design tools where necessary to include: (1) investigation on EM reflector to understand the principles of operations and assess its potential for broadband operation; (2) detailed study on possible methods to perform the desired transformation of space waves to surface waves and to elucidate the underlying physical mechanisms that will lead to possible transformation.