An ultra-wideband and low-profile electromagnetic rasorber based on ITO resistive film

In this letter, a rasorber with an ultra-wide electromagnetic (EM) wave absorption bandwidth is proposed, which is composed of multiple layers of indium tin oxide (ITO) resistive films with different structures and a metal ground. The rasorber has an absorption rate of over 90% at 1 GHz-21.2 GHz under different polarized waves vertically incident, with a relative bandwidth of 182%. When EM waves are obliquely incident, it can maintain an absorption rate of over 80% in the range of 45° under TE and TM polarization, with angular incidence stability. An improved genetic algorithm was used to optimize the rasorber performance during the design process. An array prototype of the proposed structure is fabricated for testing and the experimental results match the simulation. The proposed rasorber belongs to EM metamaterials, with a cell period size of 0.167 λL and a thickness of 0.1 λL, offering advantages in miniaturization and low-profile.