Over the years, Cognitive radio technology has dramatically influenced wireless systems in which antenna plays a significant role for interviewing spectrum sensing and underlay operations. An ultra-wideband (UWB) antenna with extended dual notch band feature is proposed in this work to meet the requirements of cognitive radios without interference from the crowded spectrum. The proposed antenna consists of stair-stepped rectangular patch with circular cut off the patch at the lower edges to which a complementary split ring resonator (CSRR) and a Patch Stub are loaded to achieve notch bands. It has an optimum dimension of 18mm by 18 mm, fabricated on FR4 material which operates between 2.64 GHz and 11.87 GHz with two notch bands at 3.293.61 GHz and 4.956.05 GHz, respectively for 5G carrier and WiFi carrier. The measured results show a peak total gain of 3.93 dBi and more than 92% radiation efficiency in the entire operating range. This is well suited for Local area cognitive radio networks; the simulated and measured results were found to be in good agreement and satisfactory.