Dual-Directional Polarization Insensitive Metamaterial Absorber based on Modified Circular Ring Structure

This paper presents the designs and analysis of dual-directional polarization insensitive metamaterial absorbers based on circular ring structure. The circular ring structure is then extended and modified to achieve new performance. The unit cell of the metamaterial consists of a circular ring copper with and without copper lines printed on dual layer of 0.8 mm thick FR4 substrate with dielectric constant of 4.6 and loss tangent of 0.019. The simulated result shows that the circular ring shape metamaterial absorber achieves very high absorbance up to 98.43%. The measurement result confirms the calculated performance in simulation. The circular ring structure can also be modified to achieve new performance such as frequency reduction and dual band response. The new modified metamaterial absorbers also confirm the polarization-independent behavior. Thin metamaterial absorbers are very important for various application such as stealth technology, radar cross section and mutual coupling reduction.