Design and analysis of frequency-independent reflectionless single-layer metafilms

We develop a theory for realizing frequency-independent, reflectionless, single-layer metafilms based on the Brewster effect. A metafilm designed based on the theory is numerically analyzed using a finite-difference time-domain method. The numerical analysis demonstrates that the reflectance of the metafilm vanishes independent of the frequency and that the metafilm behaves like an all-pass filter (with finite loss). An analysis based on an electrical circuit model of the reflectionless metafilm reveals that the energy of the suppressed reflection wave is not stored in the metafilm but is radiated to the transmission direction.