Antena gravata borboleta em geometria fractal para múltiplas frequências e grande largura de faixa

Abstract

This work presents a study on microstrip antennas in bowtie shape. It was developed the traditional model of bowtie with the purpose of verify its operating behavior according of the reflection coefficient. Results showed that this geometry operates with multiple resonance frequencies and narrow band around each. To expand the range of operation, it was used the fractal geometry of Sierpinski triangle, together with other modifications to the radiator element, in the feed system and the ground plane. For the traditional model was used feed by coaxial probe, at a point where was obtained better impedance matching. For models developed from the Sierpinski triangle, was employed the microstrip line with a quarter-wave transformers based on binomial sequence and Tschebyscheff polynomial. The designs were developed in the FR4 substrate searching acceptable performance in the point of view of return loss in broad band. The results were consistent with the demands of different radiocommunications systems in the microwave range.