Reflection of Electromagnetic Waves from Interface between Two Media with Positive and Negative Refraction Factors

New relationships for factors of reflection of electromagnetic waves from interface between two media with positive and negative refraction factors are derived which are applicable in the certain frequency range for calculation of amplitude and intensity of the reflected and refracted electromagnetic radiation when one of the media is a typical isotropic dielectric and another is a photon crystal. The anomalous increase in transmission for the photon crystal is predicted at some values of the electromagnetic radiation frequency. A new type of selective filters based on photon crystals with negative refraction factors is suggested.