Naslov
Analysis of Conformal Antennas Using Integral Approach and Moment Method

Autori
Šipuš, Zvonimir ; Milin-Šipuš, Željka ; Škokić, Siniša

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Conference on Applied Mathematics and Scientific Computing, Abstract Book / Marušić, Miljenko - Zagreb : Prirodoslovno-matematički fakultet Sveučilišta u Zagrebu, 2003

Skup
Conference on Applied Mathematics and Scientific Computing

Mjesto i datum
Brijuni, Hrvatska, 23.06.2003. - 27.06.2003

Vrsta sudjelovanja
Poster

Vrsta recenzije
Domaća recenzija

Ključne riječi
conformal antennas; Green`s functions; method of moments

Sažetak
Rapid growth in wireless communications, especially mobile communications, caused that the requirements on terminal antennas are more and more demanding. Arrays on cylindrical structures offer a possibility either to create directed beams in arbitrary direction in horizontal plane, or to create an omnidirectional pattern. Spherical arrays have possibility of directing single or multiple beams through complete hemisphere. Conformal antennas and periodic surfaces are frequently analyzed by means of the electric field integral equation and the moment method. The kernel of the integral operator is a Green's function, which is different for different structures. Planar, circular cylindrical and spherical multilayer structures have one property in common: the structure is homogeneous in two dimensions, and varies in the third dimension. For example, the spherical structure varies in radial direction and is homogeneous in q and f directions. Thus, we can call planar, cylindrical and spherical structures one-dimensional structures since they vary only in one dimension. We simplify the problem of determining the Green's functions for one-dimensional structures if we perform the two-dimensional (2D) Fourier transformation in the coordinates for which the structure is homogeneous (in the cylindrical case we perform the Fourier transformation in axial direction and the Fourier series in f direction, and in the spherical case we perform the vector-Legendre transformation). As a result, our original three-dimensional problem is transformed into a one-dimensional problem, which is much easier to solve. There are two basic approaches for determining the Green's function of general multilayer structures: either to analytically derive an expression for it and then to code this expression, or to develop a numerical routine for the complete calculation. The analytic approach requires less computer time than the numerical approach. However, it is a very laborious process to analytically determine the Green's functions for substrates with more than two layers. Therefore, in such cases it is convenient to use a numerical algorithm that determines the Green's function directly. Another disadvantage of the analytic approach is that it is valid for a very specific geometry, so that a new derivation of the Green's functions is needed if the geometry is slightly different, such as for different locations of the patch antennas inside the layers. We will present the G1DMULT algorithm that calculates the spectral-domain Green's functions for planar, circular-cylindrical and spherical multilayer structures. Sometimes it is complicate to rigorously calculate elements of the moment method matrix. In such cases approximate methods can be applied. The key point of applying the uniform theory of diffraction to conformal antenna analysis is to determine the geodesic on the antenna surface. We will describe a general ray-tracing method that is suitable for analyzing conformal antennas.

Izvorni jezik
Engleski

Znanstvena područja
Matematika, Elektrotehnika

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