When the electromagnetic wave propagates in air and it meets the object with the size less than the wavelength then this wave simply pass around this object and continues its way as if this object does not exist at all. Now imagine such situation. The antenna emit the radio waves with the wavelength of let’s say 1 meter and it meet the metallic cylinder with the height/length of 100 meters but width/diameter of 0.1 meter. What will happen? One geometric parameter (cylinder’s length) is more than wavelength, but the second (width) is less, will the radio wave pass around this cylinder or will it reflect from cylinder?