Generalized-scattering-matrix analysis of a class of finite arrays of coupled antennas by using 3-D FEM and spherical mode expansion

Performance characterization of wideband, wide-angle scan arrays of cavity-backed U-slot microstrip patch antennas

“…The cavities are recessed in a metallic plane considered as infinite in the simulations. The array is analyzed from a full-wave modular procedure [5] that comprises two steps.…”

“…The antenna is segmented into two regions delimited by ports, where modal expansions of the electromagnetic fields are used in the simulation. The first region includes the coaxial feed and part of the cavity region, and the second region comprises the U-slot patch and a semispherical computation domain where a spherical modal expansion is carried out to characterize the radiating region [5,7]. Both regions are separated by a fictitious coaxial port, as shown in Figure 1, where once again an analytical modal expansion of the fields is carried out.…”

“…The generalized translation matrix G jk associated to each pair of antennas (j,k) can be expressed as a product of matrices, which include the rotation, axial translation, and inverse rotation coefficients, and they account for the different interrelations between the spherical modes [5,7,8] of both antennas. From these relations and after different matrix operations a closed-form expression both for the overall reflection matrix of the array,…”

A Domain Decomposition Method Based on a Generalized Scattering Matrix Formalism and a Complex Source Expansion

“…In these cases, the transport matrices can be obtained in analytical form; however, the method becomes less effective if the scatterer boundary deviates from the canonical shapes. An hybrid approach combining finite element method for the analysis of the single subdomains and spherical mode expansion for the description of the coupling effects is proposed in [13]. In [3], the tangential electromagnetic fields on the subdomain interfaces are expanded on a set of basis functions, and the Boundary Element Method (BEM) or the Finite Element Method (FEM) are used to calculate the scattering matrices.…”

“…In the above mentioned methods [1][2][3][4][5][6][7][8][9][10][11][12][13][14] all the wave objects are in general involved in the interactions. On the other hand, if directive beams were used for the field expansion, the identification of interacting wave objects would assume a direct and natural geometrical interpretation and the number of connected ports could be minimized.…”