Odilon M. C. Pereira-Filho

Analysis of superstrate loaded cylindrical-rectangular microstrip antennas using the electric surface current method

This paper uses the electric surface current method to determine the radiation pattern and input impedance of cylindrical-rectangular microstrip antennas with a superstrate. The fields are solved taking into account both dielectric layers and the metallic cylinder through the proper Greens function. It also discusses the effects of varying the thickness and dielectric permittivity of the superstrate.

Cavity-backed cylindrical wraparound antennas

This paper presents a method of moments analysis of cavity backed cylindrical wraparound antennas. It shows results for radiation pattern and input impedance, and compares them with those for similar geometries. The effects of the cavity are evaluated.

Analysis of spherical-rectangular microstrip antennas

The radiation pattern of spherical-rectangular microstrip antennas is investigated using the cavity method and the electric surface current method. The thickness of the dielectric substrate and its relative permittivity are varied and the effects on the radiation pattern are analyzed.

Mutual impedance of spherical microstrip patches

Spherical microstrip antennas find important applications in aeronautics and satellite communications. Such antennas have been studied using several methods, including cavity method [1–2], electric surface current method [3], GTLM [4], and method of moments [5–11]. Method of moments was employed in [5] for determining the resonances of a circular microstrip disk mounted on a spherical surface, or in the presence of a superstrate [6]. Input Impedance of spherical circular and annular microstrip antennas were shown in [7]. Input impedance and radiation pattern of spherical quasi-rectangular patch antennas were studied in [8–10] using method of moments. The studies also included mutual coupling coefficient and arrays of quasi-rectangular patches. In [8] a modified Vector Legendre transformation using normalized associate Legendre functions was also introduced. In [11] the patch was no longer limited to a quasi-rectangular shape, and the input impedance was obtained from moment method and attachment modes. In this work (this work was partially supported by FACEPE and CNPq) we perform a full-wave analysis, using method of moments, to determine the mutual impedances of spherical microstrip patches. The patches are allowed a more general shape, following the spherical coordinates, as shown in Fig. 1. The effect of moving the patches (keeping the average widths) toward the z-axis will be discussed on both input impedance and mutual impedance of the patches.

Input Impedance of Rectangular Microstrip Antennas on Spherical Bodies using MoM and Attachment Modes

This paper presented a full-wave analysis of a spherical rectangular microstrip antenna using method of moments, emphasizing the use of an attaching current in the modeling of the patch currents and calculation of its input impedance

On the transverse variation of currents on cylindrical microstrip antennas

This paper describes the transverse variation of resonant currents on cylindrical microstrip antennas. And also attempts to improve their representation through the use of transmission line distributions, obtained using Method of Moments. Convergence of the method is shown.

Comparison of microstrip and cavity-backed cylindrical wraparound antennas

This paper presents a comparison of microstrip and cavity-backed cylindrical wraparound antennas. The antennas are analyzed using method of moments, and results of radiation patterns and input impedance are compared to each other, and to results from a commercial software. The effects of the cavity-backed confinement and of surface waves of the microstrip antenna are evaluated.

Efficient Evaluation of Singular Integrals in Moment Methods Applied to Solve Scattering Problems from Bodies of Revolution

This work proposes an efficient procedure for evaluating singular integrals arising in the moment method analysis of scattering from bodies of revolution. Perfect electric conductor, dielectric and composite bodies with different electrical sizes and different relative permittivities are analyzed by the CFIE, Muller and PMCHWT integral equation, respectively. It is demonstrated that an efficient singularity removal reduces the number of basis functions necessary to represent the equivalent current distributions

Comparison of Different Integral Equations in Moment Methods Applied to Solve Scattering Problems from Bodies of Revolution

In this paper, several integral equations derived for scattering problems are evaluated by the MoM technique and compared to each other in the numerical analysis of scattering by bodies of revolution when illuminated by plane-waves. The numerical results are compared to Mie-series analytical solutions. Dielectric and composite bodies with different electrical size and different relative permittivity (for dielectrics) are analyzed. It is shown that Muller integral equation is the most accurate solution for dielectric and layered bodies analysis, PMCHWT is the most accurate for bodies with homogeneous regions analysis