Three-dimensional ultra-broadband absorber based on novel zigzag-shaped structure.

Absorbers have potential applications in the stealth field. However, limited bandwidth and low absorption rate persist in existing methods. Moreover, absorbers working in the low frequency range (1-4 GHz) with small size are much more difficult to realize. In this paper, we propose a novel absorption structure, which combines indium tin oxide film and metal resonator. The former realizes impedance matching with free space in a broad bandwidth at moderate frequency range while the latter shows the resonant property at low frequency. Based on this absorption structure, we design the zigzag-shaped structure to realize high-efficiency and ultra-broadband absorption. To demonstrate the feasibility of our method, we fabricate a sample and perform measurements. The measurement results show that our sample can achieve ultra-broadband absorption with high-efficiency of over 90% from 1 GHz to 18 GHz, which is in good agreement with simulation results. Our findings provide a valuable technique for broadband device design, which could bring about a wide range of applications in cloaking technology.