Miniaturisation of the triangular patch antenna by the novel dual-reverse-arrow fractal

A novel geometry called the dual-reverse-arrow fractal (DRAF) is introduced, which is the combination of two dual Koch fractals. It is implemented on an equilateral-triangular patch antenna. This structure has smaller dimensions compared to the rectangular structure and has wide applications in arrays to reduce their size. Furthermore, the use of triangular elements in array leads to the decrease of side-lobe levels. Four cases of the triangular patch are compared to show that the presented fractal geometry is effective in the miniaturisation of patch antenna and decreasing its resonance frequency, while the antenna bandwidth and efficiency are kept constant. To increase the antenna efficiency, an air space is placed under the patch. Finally, a portion of the corner of fractal triangle is cut to generate circular polarisation by proper positioning of the feed points. The proposed DRAF antenna achieved 40% reduction in size compared to the similar triangular antenna. The proposed DRAF geometry has potential applications in various radiating systems and microwave devices.