Compact Nine-Way Power Divider With Omnidirectional Resistor Based on Graphene Flake

In this letter, a compact nine-way power divider with an omnidirectional isolation resistor based on graphene flake is proposed and validated. The power divider is implemented on a back-to-back double-layer microstrip structure with a common ground and multiple via holes for size reduction. In particular, a piece of a circular graphene flake loaded on a saw-tooth structure is well designed to achieve omnidirectional isolation resistor between arbitrary output ports, avoiding the traditional fussy lumped resistor welding process. Then, a nine-way double-layer broadband power divider is designed, analyzed, and fabricated, with the operating range from 1.9 to 2.75 GHz and the transmission level of -10 +/- 0.5 dB; the port-to-port isolation is better than 25 dB.