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International Journal of Antennas and Propagation
Volume 2012, Article ID 309361, 8 pages
Research Article

Planar ESPAR Array Design with Nonsymmetrical Pattern by Means of Finite-Element Method, Domain Decomposition, and Spherical Wave Expansion

1Departamento de Electromagnetismo y Teoría de Circuitos, Universidad Politécnica de Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain
2Departamento de Tecnología de los Computadores y de las Comunicaciones, Universidad de Extremadura, Avenida de la Universidad s/n, 10003 Cáceres, Spain

Received 26 June 2012; Revised 2 August 2012; Accepted 16 August 2012

Academic Editor: Z. N. Chen

Copyright © 2012 Jesús García et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The application of a 3D domain decomposition finite-element and spherical mode expansion for the design of planar ESPAR (electronically steerable passive array radiator) made with probe-fed circular microstrip patches is presented in this work. A global generalized scattering matrix (GSM) in terms of spherical modes is obtained analytically from the GSM of the isolated patches by using rotation and translation properties of spherical waves. The whole behaviour of the array is characterized including all the mutual coupling effects between its elements. This procedure has been firstly validated by analyzing an array of monopoles on a ground plane, and then it has been applied to synthesize a prescribed radiation pattern optimizing the reactive loads connected to the feeding ports of the array of circular patches by means of a genetic algorithm.