A novel compact fractal UWB antenna with dual band notched characteristics

A very compact dual band notched fractal structured antenna is proposed for UWB applications. A novel fractal patch with defected ground structure is utilized to achieve −10 dB bandwidth of 7.87 GHz from 3.77 GHz to 11.64 GHz. To notch upper WLAN band of 5.52–5.90 GHz, an S- shaped slot is introduced in the 50 Ω microstrip feed line. The X- band notch for down link of satellite communication applications from 7.22–8.16 GHz is achieved by two symmetrical L- structured parasitics on both sides of fractal patch. The proposed antenna having a compact size of 16 × 21 mm2 (0.2λ0×0.26λ0\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${0.2 \lambda }_{0}\times 0.26 {\lambda }_{0}$$\end{document}) and is fabricated on a low cost FR- 4 substrate. A maximum gain of 4.32 dBi in UWB band with gain drops to −2.53 dBi in WLAN at 5.75 GHz and −4.25 dBi in X-band at 7.35 GHz are noticed. The proposed antenna shows good similarity between simulated and measured electrical parameters such as S11, nearly omnidirectional patterns, constant gain and time domain characteristics makes it suitable for portable wireless applications.