Implementation of shunt-connected series resonators through stepped-impedance shunt stubs: analysis and limitations

In this study, the implementation of shunt-connected series resonators in microstrip technology by means of stepped impedance shunt stubs (SISS) is analysed. The main aim of the work was to determine the achievable values of resonator´s inductance and capacitance, under the restriction that the agreement between the frequency response of the SISS and that of the ideal shunt-connected LC resonator must be good in a wide band (far beyond the resonance frequency). The study is completed by considering different substrate types (with different thickness and dielectric constant) and determining the limitations of the achievable element values, by providing the allowable regions in the LC plane. Finally, the analysis is validated through the design and characterisation of different SISS structures.