Oblique Incident Reflection Characteristic Evaluation of EM Wave Absorber for 28 GHz Without Metal Backing

The oblique incidence characteristics of an electromagnetic wave absorber for 28GHz with a structure consisting of a conductive material layer and a dielectric material layer were evaluated analytically and experimentally. By optimizing the design of the conductor layer, it was confirmed that the difference in the properties at oblique incidence between with/without metal backing was little. The reflection coefficient with increasing incident angle was different between the TE and TM incident waves. Then, the polar chart was used to investigate. Matching conditions (reflectance coefficient was less than 0.1) were obtained in the angle range up to about 60° for TE incident waves. An electromagnetic wave absorber without metal backing using this structure has advantages in terms of cost, weight and flexibility in the millimeter wave band.