Characteristics of grid ferrite electromagnetic wave absorber

A novel ferrite grid electromagnetic wave absorber composed of sintered ferrite is proposed. Based on the condition that the return loss should be above 20 dB at 30 MHz, its wideband characteristics for suppressing reflections compared to a single-layer absorber are demonstrated by computer simulation. Calculating the return loss by varying the geometrical parameters of the ferrite grid, an optimum structure is determined which gives the maximum frequency band. In addition, it is found that the return loss of the grid absorber is impaired by an air gap between the ferrite and conductor. Moreover, the operating characteristics of the grid absorber are demonstrated by experimental models.