Method of Moments Simulation of Modulated Metasurface Antennas With a Set of Orthogonal Entire-Domain Basis Functions

• Published in: IEEE transactions on antennas and propagation Vol. 67; no. 2; pp. 1119 - 1130
• Main Authors: Bodehou, Modeste, Gonzalez-Ovejero, David, Craeye, Christophe, Huynen, Isabelle
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-02-2019; The Institute of Electrical and Electronics Engineers, Inc. (IEEE); Institute of Electrical and Electronics Engineers
• Subjects: Antennas; Basis functions; Boundary conditions; Computer simulation; Conditioning; Current distribution; Dielectrics; Electric fields; Electromagnetism; Engineering Sciences; Impedance; impedance boundary condition (IBC); Indexes; Integral equations; leaky-wave antennas; Mathematical analysis; Metasurfaces; metasurfaces (MTSs); Method of moments; method of moments (MoM); spectral domain methods; impedance boundary condition (IBC); method of moments (MoM); Basis functions; leaky-wave antennas; metasurfaces (MTSs); spectral domain methods
• ISSN: 0018-926X; 1558-2221
• DOI: 10.1109/TAP.2018.2880075

A family of orthogonal and entire-domain basis functions (named Fourier-Bessel) is proposed for the analysis of circular modulated metasurface (MTS) antennas. In the structures at hand, the MTS is accounted for in the electric field integral equation (EFIE) as a sheet transition impedance boundary condition on the top of a grounded dielectric slab. The closed-form Hankel transform of the Fourier-Bessel basis functions (FBBFs) allows one to use a spectral domain formulation in the method-of-moments (MoM) solution of the EFIE. Moreover, these basis functions are fully orthogonal, which implies that they are able to represent the global evolution of the current distribution in a compact form. FBBFs also present a better filtering capability of their spectrum compared to other well-known orthogonal families such as the Zernike functions. The obtained MoM matrix is sparse and compact, and it is thus very well-conditioned and can be efficiently computed and inverted. The numerical results based on the proposed decomposition are presented and compared with those based on the use of the Gaussian ring basis functions and with the full-wave analysis of MTS antennas implemented with small printed elements. A very good agreement is observed.