Dual-Band and Wide Stopband Coaxial Filters Using Open-Circuited-Stub-Loaded Resonators
Ya Xie, Fu‐Chang Chen
Abstract
Novel open-circuited-stub-loaded coaxial resonator (OCSLR) is introduced in this brief. This resonator consists of a traditional coaxial resonator, which is vertically loaded by an open-circuited stub. Based on the resonant properties, the first two resonant frequencies can be flexible controlled by properly choosing the impedance ratio and length ratio. The proposed dual-band filter is achieved by employing OCSLRs which act as dual-mode resonator. The proposed wide stopband filter is realized by two OCSLRs loaded at different heights together with a traditional quarter-wavelength coaxial resonator, resulting in the same fundamental frequencies and different harmonic frequencies. Two design examples are manufactured to validate the concept. The measure results show good agreement with simulations.