Ultra-wideband high-gain dipole antenna evolved from hexagonal Sierpinski grid fractal gasket

Ultra-wideband high-gain dipole antennas are urgently desired for mobile communications. A novel fractal-evolved dipole called modified hexagonal Sierpinski grid carpet dipole, of which size is about 1.5λ in upper band is developed. With self-similarity and periodicity of fractal geometry, the dipole antenna is excellent in performances. It has an ultra-wide bandwidth and high gain, due to a so-called ‘array effect of element antenna’. It presents a gain as high as 12.7 dBi and stable unidirectional radiation patterns within band of 2.0–3.93 GHz (BW = 65.1%). In addition, the dipole also has good cross-polarisation differentiation, high efficiency, high front-to-back-ratio, small size, low-profile (0.156λL), and light weight. A prototype was fabricated from a plastic body by 3D printing technology and then electroplated on the surface. Then, the sample was measured and compared with simulation results, and good agreements are obtained between them. So, correctness and validity of the design methodology are verified successfully. Due to these remarkable advantages, the fractal antenna is attractive to many radio services, such as mobile communications, defence and military, public security, aeronautics and aerospace, and so on.