Microwave wedge absorber design using rice husk - an evaluation on placement variation

Placement variation is one example of parameters that critically affects the performance of RF absorbers. In this work, four designed variation patterns - W, X, Y, and Z were discussed to compare the reflectivity (S₁₁) of designed wedge microwave absorbers. Two sub-shapes were investigated in this work - straight wedge and oblique wedge, each type having three variation of top width dimension. The other investigation includes performance comparison between four and nine elements´ array of straight wedges and oblique wedges. These wedge absorbers were simulated using CST Microwave Studio software, with rice husk as its material (dielectric constant, ε_r = 2.89). The wedge absorbers have been designed to operate effectively between the frequencies of 1 GHz to 20 GHz.