We present a general analysis of the tunneling process through localiz
ed resonant states between one-dimensional continuums. We show that co
mplete transfer fan occur between the continuums by creating resonant
states of different symmetry, and by forcing an accidental degeneracy
between them. The degeneracy must exist in both the real and imaginary
parts of the frequency. We illustrate the results of the analysis by
performing computational simulations on the transport properties of el
ectromagnetic waves in a two-dimensional photonic crystal. [S0031-9007
(97)05091-6].