Bandwidth Enhancement of Hexagonal Giuseppe Piano Fractal Dielectric Resonator Antenna by Introducing Four Shorting Pins

In this research, a new compact hexagonal Giuseppe Piano fractal dielectric resonator antenna (DRA) with enhanced bandwidth is introduced. An extra short-pin mode can be excited for the antenna and the frequency of the TM011 mode can remain nearly constant by loading the short pins along the nodal line of electric fields of the TM011 mode of the DRA. Subsequently, the DRA loaded with two and four shorted pins was further investigated. The findings show that the resonant frequency of the shorting pin mode is increasingly shifted upward with an increasing number of pins. With these configurations, better bandwidth is achieved for the hexagonal Giuseppe Piano fractal antenna with the four-pin DRA loaded. The final design indicates that the DRA gained an increased bandwidth (S11 10 dB) of approximately 23.66% (3.8–4.82 GHz) under dual-mode radiation, whereas the stable conical radiation patterns are retained. More importantly, the height and diameter of the dielectric radiator are kept as small as 0.09 and 0.32 free-space wavelengths, respectively.