Antennas for the microwave imaging system are large which results in higher radiation, manufacturing cost, poor radiation characteristics and it will be difficult to locate on breast tissues. We propose a wearable ultra-wide band antenna for use in the diagnosis of breast cancer bio-medical applications. The antenna has been fabricated on 1.6 mm FR4 substrate with a dimension of 28 × 14.4 mm2 and can operate between 2 GHz-12 GHz with S11<-10 dB with best radiation characteristics. The prototype of the proposed antenna was fabricated and practically tested and the results were found to be consistent with the simulated results. The proposed UWB antenna is intended to radiate and receive information covering the entire spectrum from 3 GHz to 13 GHz. For good impendence matching throughout the larger spectrum, the defected ground structure (diamond shape) was exploited. All the dimensions of the proposed design are confirmed by parametric study and optimization. The maximum simulated efficiency was ranging from 80 to 84% in the desired operating frequency. The maximum Specific Absorption Rate of the proposed antenna was 0.98 W/Kg. Therefore, the proposed UWB antenna could be the right structure for breast cancer diagnosis in terms of SAR. The antenna was found to have a substantial radiation efficiency of around 78%-84% in the desired operating bandwidth. The overall realized gain of the proposed UWB antenna was seen ranging from 1.8-4.2 dB which is sufficient for bio-medical applications. The breast phantom was modeled for the validation of the performance of the antenna and SAR was analyzed. The value of SAR of the designed antenna was observed at about 0.98 W/Kg, which is suitable for medical applications.