A Miniaturized Fractal Defected Ground Structure Super-Widedband Antenna for Wireless Communication Systems

A low profile fractal defected ground structure (DGS) antenna is presented for super-wideband (SWB) wireless communication applications. The designed antenna covers a very wide frequency range from ۱ to ۲۷.۴ GHz (impedance bandwidth of ۱۸۶%) with |S۱۱|<-۱۰ dB. Moreover, In spite of small electrical dimension of the proposed antenna (۰.۱۱ λ× ۰.۱۱ λ), a large bandwidth dimension ratio of ۱۵۳۷۲ is resulted. The SWB operation is achieved by using fractal DGS on the ground plane to improve the impedance characteristics between adjacent resonant frequencies. The antenna consists of a ۳۴×۳۴×۱.۶ mm۳ FR۴ substrate with a dielectric constant of ۴.۴ and a narrow rectangular radiator. A multi-frequency resonance characteristic is obtained by increasing the fractal slot iterations on the ground plane. The simulation results are verified by experimental measurements. Measured data are in good agreement with the simulated results. The frequency- and time-domain characteristics of the antenna including impedance matching, far-field patterns, gain, radiation efficiency, group delay, and fidelity factor are presented and discussed. The results indicate that the antenna has good performance over the entire operating bandwidth which make it very potential candidate for integration in SWB wireless communication systems.