Attenuation of Electromagnetic Fields in Pipes Smaller than the Critical Size

A theoretical and experimental discussion is given of electromagnetic fields in pipes smaller than the critical size, especially with regard to attenuation, and based upon wave-guide theory. It is shown that the rate of attenuation, as the wavelength increases and passes through the critical value, approaches a high asymptotic value. Confirmatory experimental data are given. Simple formulas for attenuation are included.