A Broadband Microwave Absorber Operating Under High-Power Antenna Irradiation

A microwave absorber is important for reducing the scattering of airborne antennas and radio-frequency systems. However, absorbed electromagnetic energy is inevitably converted into heat, and high-power antenna irradiation may cause local temperature rise and safety hazards. In this work, we demonstrated how to overcome this bottleneck to be compatible with broadband absorption and to work under high-power electromagnetic irradiation. Through the analysis of the electromagnetic-thermal characteristics of typical periodic structural units, cross-shaped and square-ring resistive-film patterns were chosen to design a broadband absorber. Finally, a dual-layer structure consisting of a lower square-ring resistive-film layer and an upper cross-shaped resistive-film layer was designed using equivalent-circuit modeling and full-wave simulation. The fabricated absorber exhibited a measured reflection response below -10 dB from 5.1 to 18 GHz. When the absorber is illuminated by a high-power antenna, its steady-state temperature is only 59.7 °C. These results indicate that the proposed scheme can balance broadband microwave absorption and thermal-management capability, providing a feasible route for absorbers used in high-power antenna irradiation environments.