Electromagnetic wave attenuation in the superconducting waveguides at frequencies above the critical value

The behavior of attenuation factor α(ν) in a wide relative frequency rAe 1<ν<∞ (ν=f/fc) at microwave energy transmission by the round superconducting waveguides is investigated. It is revealed that, despite of increasing of surface resistance with increasing ν, α(ν) sharply decreases in the rAe 1<ν<4 and tends to characteristic limit αmin at ν→∞. Such behavior α(ν) is due to joint appearance of opposite influences of wave frequency and surface resistance of the superconducting material. The waveguide with radius r=1 m, made of high-temperature superconductor, has the highest value of efficiency (98% at ν=4)