Bandwidth enhancement of artificial magnetic conductor-based microwave absorber using square patch corner cutting

A method for enhancing the bandwidth of microwave absorber is proposed. The absorber which is constructed from artificial magnetic conductor (AMC) consists of an array of copper square patches printed on a grounded 3.2mm thick FR4-Epoxy dielectric substrate. The proposed method is carried out by reducing the area of square patches; in this case, it is conducted by cutting the corners of square patch yielding a patch in octagonal shape. It shows that the proposed method which yields an equilateral octahedral patch with size of 9.53mm on each edge can widen the bandwidth up to 29.5% compared to the bandwidth of square patched absorber. The method also increases the resonant frequency of microwave absorber from 2.4GHz to 2.84GHz. In addition, to improve the value of reflection coefficient, external resistors are put between adjacent patches which are parallel to the electric field excitation.