The intermodulation power and quality factorQofhigh-Tcsuperconducting microstrip resonators with different shapes is calculated. Acute corners increase the losses and the intermodulation power. The influence of normal conducting regions is investigated. The case of two microstrips carrying in phase or out of phase currents is also studied. The losses and the intermodulation power are significantly reduced if the currents are in phase in the two microstrips compared to the mode with out of phase currents. ©1997 American Institute of Physics.