Microwave Coaxial Cavities with High T sub c Superconducting Ceramic Center Conductors

Microwave cavities are a key ingredient in microwave devices. They form an important part of all oscillators and are used extensively as filters, diplexers, wave meters, echo boxes, frequency discriminators and power splitters. We have made some coaxial microwave cavities with superconducting center conductors. These cavities have a substantially higher unloaded "Q" than their all copper counter parts. We will discuss cavity construction, ceramic preparation, measuring methods, magnetic field effects and potential applications. Besides being useful for devices these cavities serve as vehicles to the physics and materials science of high T sub c superconducting ceramics.