Dual-band filtering power divider with capacitor-loaded centrally coupled-line resonators

In this study, a dual-band filtering power divider with capacitor-loaded centrally coupled-line resonators (CLCCLRs) is presented. The proposed design utilises four CLCCLRs, two resistors and one inductor to achieve the dual functions of dual-band filtering and power division. By altering the values of the capacitors loaded at the ends of the coupled lines, the centre frequencies of the two passbands can be adjusted independently. It is noted that changing one passband will not affect the other. For demonstration, a microstrip filtering power divider is designed, fabricated and measured. Under different values of the loaded capacitors, experimental results show that the lower band centre frequency varies from 0.7 to 1.0 GHz with the upper band fixed at 1.75 GHz, whereas the upper band centre frequency varies from 1.65 to 1.95 GHz when the lower band is fixed at 1.0 GHz. The measured results show good agreement with the simulations.