In this paper a printed regular hexagonal slot antenna with a hexagonal stub fed by a coplanar waveguide line has been considered for ultra wide bandwidth. This antenna is then modified to obtain dual band rejection. The Wireless Local Area Network (WLAN) and Wireless Microwave Access (WiMAX) band rejections are realized by incorporating a C-shape slot within the exciting stub as well as a couple of Z-shape open circuit stubs symmetrically inserted at the edge of the slot. The length and width of the C-shape slot and Z-shape stub offer sufficient freedom for selecting and shifting the notch bands. Magnitude of S11, impedance, gain and radiation characteristics of them are studied and discussed here. From the measured results, it has been observed that the impedance bandwidth, defined by magnitude of S11 ≤ -10 dB, reaches a value of 8.18 GHz (2.96~11.14 GHz) except dual frequency stop bands of 3.28-3.7 GHz and 5.1-5.90 GHz. From the experimental results, it is observed that the radiation patterns are omnidirectional in the H-plane and dipole in nature in the E-plane. The antenna gain varies from 4.8 dB to 5.3 dB over the whole operating band excluding the notch bands. Surface current distributions are used to analyze the effects of the C-slot and Z-shape stub. Measured group delay has very small variation within the operating band except notch bands and hence the proposed antenna may be suitable for UWB applications.
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