Transmission Characteristic of Electromagnetic Wave from the Earth into the Air

This paper presents a basic idea to connect an electromagnetic wave propagation between the air and the earth. When an electromagnetic wave escapes into the air from the earth, its refraction angle rapidly approaches 45 degrees right after a very small incidence degree in the case of ELF wave frequency. As the wave frequency increases, the refraction angle exponentially approaches 90 degrees which means the direction of propagation follows the earth surface. This phenomenon has an useful meaning to lessen an interference from a buried source.