Design Method for Compact Multifunctional Reconfigurable Filtering Power Divider on a New Tunable Three-Port Multi-Mode Topology

In this paper, a new effective approach is proposed to design compact multifunctional reconfigurable filtering power divider (FPD) based on a developed tunable multi-mode FPD topology. Different from conventional tunable FPD method by cascading tunable filter with power divider (PD), and double tunable filtering structures based on the tunable FPD method, it provides one promising solution of high operation performance, miniaturization and design flexibility enhancement etc., for industrial multi-functional modern wireless communication systems. By reformulating the traditional coupling matrix in terms of element-variable coupling coefficients for the developed tunable FPD topology, bandwidth (BW), center frequency (CF), as well as power division ratio (PDR) tuning are well accounted, which can help guide a new class of tunable FPD designs. For demonstration, a new second-order tunable FPD with only one common ring loaded coupled line tunable resonant unit is implemented as an example without losing generality. Higher-order tunable FPD case is further discussed and investigated by freely generalizing the FPD structure through the adoption of different tunable resonant units without dramatically increasing circuit complexity and size. Experimental results indicates that an improved performance (wider tuning range for CF, BW and PDR with nice isolation and matching), a very compact size and flexible design are achieved in the proposed work, which stands out from those in the literature.