A Near-Omnidirectional, Low-Profile, Broadband, Metamaterial Absorber Based on Characteristic Mode Analysis

In this paper, a low-profile, broadband metamaterial absorber with the advantage of near-omnidirectional absorption for TM polarization, is developed based on characteristic mode analysis (CMA). By utilizing CMA to synthesize omnidirectional radiation pattern of the absorber's unit-atom under full PEC condition, the developed absorber can then convert the omnidirectional radiation pattern into near-omnidirectional absorption pattern based on dissipation tailoring. The developed absorber is three-dimensional, and its top layer is patch-type with broadband and angle-stable absorption within small incident angles. And the middle part is a lossy pillar to provide broadband absorption at large incident angles. The simulated results demonstrate that, in the frequency range of 1.2-3.0 GHz, corresponding to the FBW of 85.7%, the absorption of TE-polarized wave is over 90 % when the incident angle is less than 40°. For TM polarization incident wave, the absorption is over 90% when the incident angle is less than 80°.