GA-FDTD Based Design of Metamaterials Yuehe Ge, and Karu P. Esselle [e-mail], [e-mail]

1
GA-FDTD Based Design of Metamaterials Yuehe Ge,
and Karu P. Esselle yuehe_at_ics.mq.edu.au,
esselle_at_ics.mq.edu.au
www.elec.mq.edu.au/celane

• characterisation of periodic metamaterials. With
  this method, the analysis of the periodic
  structure has been reduced to that of a single
  element, making the calculation very efficient.
• Genetic algorithms (GAs) fall under a special
  category of optimisation schemes that are robust
  and stochastic. Based on the principle of natural
  selection, they are particularly effective in
  searching for global maxima in a multidimensional
  and multimodal functional domain. For
  electromagnetic problems, GAs have been
  successfully applied to the design of broadband
  or multi-band antennas, spatial filters, and
  microwave absorber synthesis
• Combining FDTD method and GAs, a GA/FDTD
  technique is developed for designing and
  optimising periodic metamaterials
• With the use of the GA/FDTD technique,
  single-band and multi-band AMC surfaces are
  successfully designed using frequency-selective
  surfaces (FSS) and mushroom-like high-impedance
  surfaces

• Introduction
• Metamaterials are artificial composite materials
  with novel characteristics that are not
  achievable from conventional materials.
• Novel properties of metamaterials include
  in-phase reflection, band-gap, effective negative
  permittivity or permeability or both,
  negative-index, etc. The corresponding
  metamaterials are also referred to as artificial
  magnetic conductor (AMC, in-phase),
  electromagnetic band-gap (EBG) structure or
  photonic band-gap (PBG) structure in optical
  domain, single-negative (SNG) or double-negative
  (DNG) or left-handed (LH) media, negative-index
  materials (NIM), etc.
• Metamaterials based on periodic structures are
  popular at present because effective techniques
  are available for characterisation of them.
• FDTD method with periodic boundary conditions
  (PBC) and perfectly matched layer (PML) has been
  developed for

Reflection phase of the mushroom-like structure
2
Dispersion diagram for the NRI lumped elements
loaded structure 1
Dispersion diagram for the Mushroom-like EBG
structure 2
Basic algorithm based on GA-FDTD method
Designed single-band PEC-backed FSS, and its
reflection phase
Designed dual-band PEC-backed FSS, and its
reflection phase
Designed dual-band mushroom-like structure, and
its reflection phase
1 Kokkinos, T., Islam, R., Sarris, C. D., and
Eleftheriades, G. V. Periodic finite-difference
time-domain analysis of loaded transmission-line
negative-refractive-index metamaterials, IEEE
Trans. Microw. Theory Tech., 2005, 53, (4), pp.
1488-1495 2 Sievenpiper, D., Zhang, L., Broas,
R. F., Alexopolous, N. G., and Yablonovitch, E.
High-impedance electromagnetic surfaces with a
forbidden frequency band, IEEE Trans. Antennas
and Propag., 1999, 47, (11), pp. 2059-2073