Design of Multifunctional Multiway Filtering Power Dividers Based on Tri-Mode Resonators

This article presents an innovative design methodology for multiway filtering power dividers that can perform both power splitting and filtering functions in a compact package. In this methodology, tri-mode resonators are used to achieve circuit miniaturization and a wide stopband. To validate the methodology, the four-, six-, and eight-way filtering power dividers based on tri-mode stub-loaded resonators were designed and fabricated; their circuit areas were small at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.089\lambda _{g}^{2}$ </tex-math></inline-formula>, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.108\lambda _{g}^{2}$ </tex-math></inline-formula>, and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.102\lambda _{g}^{2}$ </tex-math></inline-formula>, respectively. The study determined that introducing additional transmission zeros can enhance the frequency selectivity and stopband attenuation. Furthermore, incorporating appropriate resistors can improve the output port return losses and port-to-port isolation. Finally, both simulations and experimental measurements confirmed that the proposed multiway filtering power dividers are compact and have high frequency selectivity, high isolation, and wide stopbands, making them suitable for modern wireless communication systems.