HTS resonators and filters

Among the most important applications of HTS microwave technology are high- performance passband filters because they can be made in planar configurations. Filters are often the dominant contributors to system volume, in particular when banks of low- loss filters are required. In order to realize passband filters with low loss, narrow bandwidth and high selectivity, it is necessary to use high-Q structures which, in conventional technology, can only be obtained at the expense of high volume. HTS planar configurations like microstrip or coplanar waveguide, on the other hand, have Q comparable to microwave cavities at a much smaller volume (1) and so HTS is an attractive approach to reducing the volume of high-performance filters.