According to the response of the thin wire array to the incident electromagnetic wave and the equivalence relation of uniform medium and uniform transmission line

the equivalent circuit for the thin wire array of metameterial is presented while a plane wave is propagating through it.The effective permittivity model of the asymmetric wire array is derived based on the circuit theory.And the validity of the model is proven by the numerical simulation.The description of theoretical derivation exhibits clear physical concepts and provides a new approach to understand the minus permittivity effect of the thin wires array from the macrophysics.