Rapid development in high speed wearable electronics, on the other hand, puts health threats due to the radiation effects caused by the Antennas in the system. Hence, Electromagnetic (EM) radiation shielding continues to be an inevitable measure. To provide EM radiation shielding, the work proposed focuses on the design of Frequency Selective Surface (FSS) operating in a wide range of stopband. The fundamental method used for achieving wide stop band response is the square ring based method. Using the enhanced version of the square ring, wide stopband range from 3 to 18 GHz was achieved. The unit cell dimensions are 11x11 mm2, with a thickness of 0.8mm, developed in a completely flexible Jean material. To achieve wide stop band response, each stage in the design is connected with the previous stage. Due to the symmetric structure, the FSS remains insensitive to polarization. On minimizing grating lobes by maintaining proper periodicity, angular stability up to 80° has been achieved. A high shielding effectiveness of 40 dB has been achieved due to the minimum S21 values. Robust behavior is witnessed under bending scenario due to the flexible nature of the FSS. On-antenna verification is also carried out to verify the effectiveness of the FSS. 100% gain improvement and 70% efficiency improvement were witnessed. The average polarization shift and angle mean deviation were 4.2% and 3.8%, which were the most minimum values. The obtained simulation results were validated by an equivalent circuit model (ECM) and further confirmed through experimental results of the fabricated prototype. With these results achieved, the FSS remains as a promising candidate with wide stop band, high degree of angular stability with minimum polarization shift and angle mean deviation.