Simulation Analysis of a Bidirectional Absorptive Common-Mode Filter for Wi-Fi 5 Applications

This paper proposes a simulation analysis of a bidirectional absorptive common-mode filter (A-CMF) using two simple C-shaped coupling defected ground structures (DGSs). The proposed filter is designed on the defected ground plane of the printed circuit board along a differential stripline pair, where the filter requires only 2 additional resistors to obtain bidirectional absorption advantages. In the frequency domain, the simulated differential-mode insertion loss (S
dd21
) is defined as a −3 dB cutoff frequency and is obtained up to 24.7 GHz. Over 80% of common-mode (CM) noise is absorbed in the 4.95 to 6.26 GHz frequency range. The fractional bandwidth corresponding to the CM noise absorption band is 23.4%. The proposed filter can be widely used to reduce the radiated electromagnetic interference in Wi-Fi 5 wireless communication applications. It can also be used in 5G mobile network applications such as the Frequency Range 1 (FR1) band from 5200 to 5900 MHz.