Broadband amplitude-tunable absorber based on plug-in structure

An active metasurface microwave absorber with reconfigurable absorption intensity is proposed for S, C, and X microwave-band applications. The metasurface unit adopts a simple split ring resonator (SRR) to form a vertically periodic cross-grid array and uses a size-scaling effect to construct a double-layer structure with structural similarity, expanding the absorption bandwidth. To achieve broadband impedance matching, a PIN diode is placed into the resonant ring opening. By optimizing the resistive loss of the three-dimensional structure through dispersion engineering, the designed double-layer plug-in structure absorber can achieve adjustable absorption amplitude within a wide frequency range of 2-12GHz, and the reconfigurable absorption intensity can reach up to 16dB. Then, the sample prototype is fabricated for demonstration, and the measurement result is consistent well with the simulation one. Furthermore, the structure demonstrates comprehensive advantages in terms of dynamic fine-tuning, lightweight design, and ease of processing. The research results have certain application value in the intelligent stealth design of weapons and equipment.