This work introduces a miniaturized monopole antenna based on metamaterials for breast cancer detection. The proposed antenna is designed on a low-cost FR4 substrate with a dielectric constant of 4.4, loss tangent 0.025 and thickness of 1.6 mm. For gain enhancement, the designed antenna is equipped with a frequency selective surface (FSS) on its back side. The suggested antenna obtains a broad bandwidth (S11> 10 dB) between 3.4 and 9 GHz, with a peak gain of 6.2 dBi at 5 GHz. The proposed work also achieves a maximum gain enhancement of 4.7 dBi with the addition of FSS at the back side of the antenna. The Specific absorption Rate (SAR) study of the antenna with a realistic hemispherical breast phantom modelled in the simulator is performed to assess the impact of radiation on the human breast. It is observed that the proposed antenna complies with the International limits when averaged over 10g of tissue. © 2022 IEEE.