Angle- and polarization-insensitive broadband metamaterial absorber using resistive fan-shaped resonators

In this paper, we propose an angle- and polarization-insensitive broadband metamaterial absorber with a resistive fan-shaped resonator. First, the symmetric fan-shaped resonator is designed, and four lumped resistors are loaded in the gap between each fan-shaped circular sector on the top layer to increase the bandwidth. Based on the circuit parameters, the periodic structure of the fan-shaped resonator is designed using full-wave analysis. The proposed absorber is fabricated using a printed circuit board process in a single layer. The experimental results indicate that an absorptivity value greater than 96% was achieved in the frequency range of 7–12.8 GHz for all polarization angles at normal incidence. Under oblique incidence, the measured absorptivity was greater than 90% in the range of 7–12.1 GHz when the incident angle varied from 0° to 45° in the transverse electric mode. In the transverse magnetic mode, the measured absorptivity was greater than 90% between 7.1 and 9.3 GHz when the incident angle varied from 0° to 45°.