Synthesis and Validation of a Cu Meta-Based Wideband Microwave Absorber on an Antenna Array

Meta copper (Cu) material called nanotwin crystalline copper metal (C2101, Kopu Tharma Loham) fabricated on the basis of ancient Indian metallurgical techniques has been originally used here as an absorbing material. The research attempted here is to explore the electromagnetic properties experimentally over a wide range of frequency covering X, Ku, K and Ka bands. The dielectric constant and loss tangent of Cu meta material are high in the X range making it a good candidate for the successful design of an absorber. Along with that, the melting point of Cu meta is also increased to 1135 degrees C which is otherwise 1085 degrees C as per international copper standards, hence making the absorber thermally stable. The particle size of Cu meta material, when measured with the x-ray diffraction method, is decreased from 50 mu m to 100 nm, placing it in a nanomaterial category. An absorption bandwidth of 35.58 GHz is obtained, ranging from 1 GHz to 36.58 GHz. After testing, the absorber is finally integrated with a two-element rectangular patch array for substantial applicability. The radiation pattern plot shows a remarkable reduction in side lobe level of the array from 3.737 dB to 1.158 dB after placing the Cu meta material absorber. The beam width narrows down from 70 degrees to 44 degrees with a slight increase in the amplitude of the major lobe from 5.494 dB to 6.341 dB while retaining the pattern symmetry.