@misc{10481/70397,
year = {2021},
url = {http://hdl.handle.net/10481/70397},
abstract = {The word radome is a contraction of radar and dome. The function of radomes is to
protect antennas from atmospheric agents. Radomes are closed structures that protect the antennas
from environmental factors such as wind, rain, ice, sand, and ultraviolet rays, among others. The
radomes are passive structures that introduce return losses, and whose proper design would relax
the requirement of complex front-end elements such as amplifiers. The radome consists mostly
in a thin dielectric curved shape cover and sometimes needs to be tuned using metal inserts to
cancel the capacitive performance of the dielectric. Radomes are in the near field region of the
antennas and a full wave analysis of the antenna with the radome is the best approach to analyze its
performance. A major numerical problem is the full wave modeling of a large radome-antenna-array
system, as optimization of the radome parameters minimize return losses. In the present work, the
finite difference time domain (FDTD) combined with a genetic algorithm is used to find the optimal
radome for a large radome-antenna-array system. FDTD uses general curvilinear coordinates and
sub-cell features as a thin dielectric slab approach and a thin wire approach. Both approximations
are generally required if a problem of practical electrical size is to be solved using a manageable
number of cells and time steps in FDTD inside a repetitive optimization loop. These approaches are
used in the full wave analysis of a large array of crossed dipoles covered with a thin and cylindrical
dielectric radome. The radome dielectric has a thickness of ~λ/10 at its central operating frequency.
To reduce return loss a thin helical wire is introduced in the radome, whose diameter is ~0.0017λ
and the spacing between each turn is ~0.3λ. The genetic algorithm was implemented to find the
best parameters to minimize return losses. The inclusion of a helical wire reduces return losses by
~10 dB, however some minor changes of radiation pattern could distort the performance of the whole
radome-array-antenna system. A further analysis shows that desired specifications of the system are
preserved.},
organization = {Spain, MINECO, grant number FIS2017-
90102-R},
publisher = {MDPI},
keywords = {Radomes},
keywords = {FDTD},
keywords = {Sub-cell features},
keywords = {Curvilinear coordinates},
keywords = {Genetic Algorithm},
title = {Design & Optimization of Large Cylindrical Radomes with Subcell and Non-Orthogonal FDTD Meshes Combined with Genetic Algorithms},
doi = {10.3390/electronics10182263},
author = {Navarro Camba, Enrique and Porti Durán, Jorge Andrés and Salinas Extremera, Alfonso and Navarro Modesto, Enrique and Toledo Redondo, Sergio and Fornieles Callejón, Jesús Francisco},
}