  We demonstrate analytically and numerically that the dispersive Dirac cone
emulating an epsilon-near-zero (ENZ) behavior is a universal property within a
family of plasmonic crystals consisting of two-dimensional (2D) metals. Our
starting point is a periodic array of 2D metallic sheets embedded in an
inhomogeneous and anisotropic dielectric host that allows for propagation of
transverse-magnetic (TM) polarized waves. By invoking a systematic bifurcation
argument for arbitrary dielectric profiles in one spatial dimension, we show
how TM Bloch waves experience an effective dielectric function that averages
out microscopic details of the host medium. The corresponding effective
dispersion relation reduces to a Dirac cone when the conductivity of the
metallic sheet and the period of the array satisfy a critical condition for ENZ
behavior. Our analytical findings are in excellent agreement with numerical
simulations.
