  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.
