Ultra-Wideband Antipodal Tapered Slot Antenna with Reflectionless Notched Band

In this letter, an ultra-wideband (UWB) antipodal tapered slot antenna with reflectionless notched band is proposed and investigated. The proposed antenna uses an integrated absorptive bandstop filter (ABSF), consisting of two quarter-wavelength open-circuit stubs and a 50 resistor, to form a reflectionless notched band. Consequently, the input energy at the notched frequency is absorbed by the resistor rather than reflected. An antenna prototype is designed and fabricated to validate the design. Both simulated and measured results present that the realized gain drops over 40 dB at 5.5 GHz, and the reflection coefficient is below -10 dB from 3.1 to 10.6 GHz. Besides, a low ringing level of -23.4 dB of the measured reception pulse shows a good time-domain performance. Therefore, the proposed antenna could be applied in UWB short-pulse system to inhibit the 5-GHz WLAN interference.