A Resistor-Free Absorptive Common-Mode Filter Using Gap-Coupled Resonator

This letter proposed a resistor-free absorptive common-mode filter (A-CMF). Also, a novel methodology of CM noise absorption is introduced. By making use of the dielectric loss of printed circuit board (PCB), CM noise is absorbed in the proposed A-CMF at 2.45 GHz without using surface-mount resistors. In this letter, an equivalent circuit model is built, analyzed, implemented, and fabricated on a four-layer PCB. Finally, the measured results are compared with the simulated ones, where a very good agreement can be found.