Tri-band superconducting filter based on crossed resonators with controllable coupling and feeding structures

摘要

In this article, a compact tri-band high-temperature superconducting filter withcontrollable coupling and feeding structures based on crossed resonator whichconsists of two-end-open UIR with a short stub and an open stub shunted atthe resonator center is proposed. Due to the symmetrical structure of the proposedresonator, the odd- and even-mode analysis method can be used to derivetheir resonance frequencies. Then, a capacitance-loaded microstrip line isadded between the resonators to flexibly control the bandwidths. Furthermore,one tapped line and one coupled line are utilized to realize the acquired externalcoupling under prior specifications. For demonstration, a tri-band filteroperating at 1.6 GHz (Global Positioning System), 2.45 GHz (Wireless LocalArea Networks), and 3.5 GHz (WiMAX) is designed, analyzed using the electromagneticsimulator, and fabricated using an Yba_2Cu_3Oy thin film on an MgOsubstrate. The measured results agree well with the simulated ones.