Jose M. Gil

Frequency Notched UWB Planar Monopole Antenna Optimization Using a Finite Element Method-Based Approach

The objective of this work is the design and optimization of an ultrawideband (UWB) planar monopole antenna with frequency-notched behavior intended to get rid of the 5-6 GHz frequency band for WLAN compatibility purposes. An optimized profile UWB planar monopole designed by means of a Simulated Annealing algorithm and full three-dimensional finite element method, detailed in a companion paper, was considered as the design starting point. In order to design the band-notched rejection no full finite element analysis is carried out on each profile modification as is usual. The procedure is based on a genetic algorithm and a multipurpose admittance matrix approach instead. Artificial ports are allowed in the computational domain and an admittance-type matrix comes up. As a result, a multiport network describes the electromagnetics within the analysis domain. Circuit manipulations of this network efficiently outperform full-wave analyses for different monopole modifications, thus making it possible to use this strategy in a computer aided-design scheme.

CAD of axisymmetric antennas through finite element and global optimiser

This paper addresses the analysis and design of axisymmetric horn antennas with arbitrary shape. The horns can be empty or loaded with one or more dielectric materials. These materials can even be uniaxially anisotropic ones. Corrugated horns can also be studied. The analysis method based on a Segmentation technique, the Finite-Element and a Matrix Lanczos-Padè algorithm (SFELP) efficiently finds the radiation patterns, the directivity and the return losses. This efficiency allows the use of this technique in connection with a Simulated Annealing algorithm adapted to electromagnetic problems.

Rotation of curl-conforming elements for a frequency stable application to the Surface Integral Equation

Method of Moments (MoM) transforms a functional operator equation into a matrix equation. When the operator is the surface integral, its solution is useful for the study of antenna and scattering problems involving homogeneous objects.

Radiation pattern conforming in UWB monopole antenna by means of dielectric coating profile optimization

A monopole antenna enveloped with a dielectric coating has been designed for best matching combined with radiation pattern stability in the 3–GHz frequency band. The dielectric coating profile has been modified in order to focus electromagnetic fields and behave like a lens. In order to obtain the best results possible, a global optimization has been performed on the dielectric coating profile. Taking into account that changes in the profile of a dielectric situated close to the monopole provoke important changes in the input impedance of the antenna, the monopole profile has also been included in the global optimization in order to increase matching. As a result from the optimization process, an optimized profile antenna has been obtained. Simulated return losses fall below the −13.5dB for the entire frequency band. Stable radiation patterns have been obtained for the desired direction of radiation, namely θ = 60°. This direction can be changed, as θ = 60° is arbitrarily chosen as an example. For this direction, the mean value of the directivity is 4.5dBi with a standard deviation of 0.38dBi across the entire frequency band. These results have been compared with those of commercial software (HFSS) for validation purposes. Good agreement has been obtained between both.