Microstructure and RF property correlation in HTS films

In this paper we report on the assessment of a range of HTS thick and thin films using a small dielectric resonator, operating near 10 GHz, capable of measuring film areas approximately 3 mm in diameter. This is achieved with the utilisation of high permittivity rutile dielectric resonators operating in the TE/sub 01/spl delta// mode which have a permittivity of approximately 105 at 77 K. Some HTS thick films have well-defined grains which are larger than the measurement area, and thus the influence of grain boundaries and other microstructural features on the RF properties of the films can be quantified directly. The dielectric loss of the rutile at 8 GHz was measured and the housing losses due to the normal copper enclosure were calculated by Superfish, a finite difference programme for the solution of modes with cylindrical symmetry.