Dielectric, also known as relative permittivity, is a unitless value that determines how fast EM waves travel in a specific medium. Its values...

Dielectric, also known as relative permittivity, is a unitless value that determines how fast EM waves travel in a specific medium. Its values range from 1 to 81, with lower values being better for GPR. Air, which is the best medium for radar waves has a value of 1 and seawater has a value of 81. Metal objects have infinite dielectric.