Shunted-Line Stepped-Impedance Resonator

This article provides an extensive review of dual-band bandpass filter designs and discusses the pros and cons of these design methods. The behavior of an SLSIR proposed by the authors shows that two passbands can be generated without using external dual-band impedance transformers. Furthermore, by using the design curves shown in this article, the k and the Qe, which are used for the synthesis of a dual-band bandpass filter, can be accurately calculated. Two examples of dual-band bandpass filters operated at 1.9/5.7 and 2.45/5.7 GHz with different bandwidths was presented to show details of the design technique. The simulation and measurement results shown are in good agreement. The resulting SLSIR dual-band filters using this technique not only provide controllable responses but also have high frequency selectivity and good impedance matching with considerable size reduction. Finally, a performance comparison comparing the technique in this article with previous design methods is listed in Table 3. The design methodology should be useful in dual-band RF transceiver design.