Compact Wideband Absorptive Filtering Power Divider With a Reused Composite T-Shape Network

This paper presents a compact structure for the filtering power divider (FPD) with wide absorptive bandwidth as well as good isolation between the output ports. A composite T-shape network that consists of a pair of resistors and a central shorted stub is used for realizing good isolation and absorption simultaneously. The isolation resistors that are essential in the FPD can be shared to absorb the signal reflected back to the input port. To enhance the absorption performance, only one synergistic absorptive stub is required and added to the input port. It allows the absorption performance to be independently controllable without affecting the passband response. The dual functions of wideband filtering response and power division are achieved by integrating the power divider and the bandpass filter using a compact three-line coupled structure. A pair of shorted stubs loaded at the ends of coupled-feed lines for outputs can provide controllable passband bandwidth and transmission zeros. To verify the proposed design concept, the multifunctional FPD with the compact structure is fabricated and measured. Good agreements between the measured and simulated results verify the calculated predictions.