Coplanar waveguide fed ultra-wide band printed slot antenna with dual band-notch characteristics

In this paper, a coplanar waveguide (CPW) fed wide bandwidth T-shaped slot antenna with dual band-notched characteristics is proposed for Ultra-wideband (UWB) applications. The dual band-notches in WIMAX(3.3–3.7GHz) and WLAN(5.15–5.825GHz) applications have been realized by etching an inverted U-slot resonator inside open circuited feeding stub as well as symmetrically placed a pair of straight slit in the ground plane. The proposed antenna exhibits an impedance bandwidth of 8.16 GHz starting from 2.52 GHz to 10.68 GHz that gives a fractional bandwidth of 123.6% for return loss less than or equal to −10 dB excluding the two rejection band from 3.28 to 3.9 GHz and 5.15 to 6.36 GHz having rejection level return loss of −3.3dB and −2.1dB respectively. The antenna gain varies from 3.5 dBi to 7.1 dBi over the entire UWB region excluding at notch bands. Surface current distributions are shown to analyze the effects of slots. The proposed antenna with overall size of 35×36×1.6 mm3 also achieves constant gain, stable radiation pattern, constant group delay and high radiation efficiency in the pass band.