The Design and Measurement of an Ultra-Wideband Microwave Absorbing Material

In order to achieve the ultra-wideband wave absorption requirement, a multi-layer microwave absorbing material is proposed. Two types of periodic patterns are designed and manufactured with ITO (Indium Tin Oxide) film on PET (polyethyleneterephthalate) material. Then the ITO-PET structures are placed on top of the PMI (polymethacrylimide) foam layers to form two types of ITO-PET-PMI layers. Multi-layer composite material is made by alternately stacking up two types of ITO-PET-PMI layers to form an eight-layer structure. The entire structure is numerically designed and optimized to achieve more than 90% of the microwave absorption, which covers the complete C-Ku band and part of the S-band. This wave absorption performance remains stable for oblique incidences, and it is polarization-independent in nature because of its high symmetric structure. The reflectivity measurement based on the arch method was performed on the fabricated material sample to verify the numerical design. A good match was observed between the experimental and numerical results.