Basic operations of open-ended resonators and their application to microwave filters

According to required filter responses, applications to microwave filters on the basis of open-ended resonators are systematically studied. First, an intrinsic property of the open-ended resonator with a tap-coupling is discussed. Second, the basic properties of various open-ended resonators are examined theoretically for improving spurious responses and realizing a dual-passband response. The examples for filters based on combination of the intrinsic property of the tap-coupling and various open-ended resonators are also provided. These results lead us to the conclusion that the combination of the tap-connection and various open-ended resonators are of great use for practical filter responses