A novel tapered slot antenna (TSA) with 3.5/5.5 GHz dual band-notched characteristics for ultra-wideband (UWB) radios is proposed in this paper. To realize dual band-notched characteristics at the TSA, we employ (a) a pair of nested C-shaped stubs beside the feed line and (b) a broadband microstrip-to-slot-line transition with an Archimedean spiral-shaped slot. The proposed antenna has been successfully simulated, implemented, and measured. An equivalent circuit model of the proposed antenna is

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... also presented to discuss the mechanism of the dual band-notched TSA. The measured data for the optimized case show the bandwidth for the VSWR < 2 to be 9.2 GHz (from 2.4 to 11.6 GHz) with two notched bands of 3.1-4.0 GHz (WiMAX band) and 5.1-6.2 GHz (WLAN band), respectively. The measured electrical parameters of the proposed antenna and its radiation patterns show excellent performance with good pulse handling capabilities. Also, the 3.5/5.5 GHz dual band-notched characteristics are achieved without increasing the size of the single band-notched TSA reported previously.