Abstract
A detailed analysis of microwave transmission through high-Tc superconducting thin films in a waveguide has been presented. A method to calculate the complex conductivity and hence the surface resistance and the penetration depth from the transmission coefficient S21 for films of thickness smaller than the penetration depth has been given. Verification of the method has been performed for 12 GHz transmission through YBa2Cu3O7 thin films prepared on LaAlO3 substrate in the K-band waveguide.