1. A method for reconstructing an image using electromagnetic waves, comprising: acquiring a measurement value of the electromagnetic waves that are radiated by a transmitting antenna and propagate through an image reconstruction region; setting a plurality of predetermined meshes in the image reconstruction region; generating a matching system matrixes using basis functions related to the plurality of predetermined meshes; generating a smoothed Green's function matrix using the generated matching system matrix; generating an electromagnetic wave calculation value through performing of a forward electromagnetic analysis with respect to the image reconstruction region on the basis of the generated smoothed dyadic Green's function matrix; calculating a misfit between the acquired electromagnetic wave measurement value and the generated electromagnetic wave calculation value, and checking whether a the calculated misfit error satisfies a predetermined optimization determination condition; updating the dielectric parameters at the meshes if the predetermined optimization determination condition is not satisfied; and outputting a reconstructed image in the image reconstruction region when the predetermined optimization determination condition is satisfied.