A Novel RFI Mitigation Method Using Source Rotation
Qiaolei Huang, Ling Zhang, Jagan Rajagopalan, Deepak Pai, Chen Chen, Amit Gaikwad, Chulsoon Hwang, Jun Fan
Abstract
This article proposes a novel radio frequency interference (RFI) mitigation method and applies it to a real consumer electronic device. Through near-field scanning, an equivalent dipole moment of the noise source containing the CPU and DDR memory chip is reconstructed. The near-field components of the victim Wi-Fi antenna are measured to obtain the transfer function. By determining the relationship between the dipole moment and the antenna near field, the noise source is rotated by a certain angle to reduce RFI. Rotating the source to reduce RFI is implemented in such a way that it does not compromise the signal integrity, and it does not require an additional shield can. New boards with the suggested changes are fabricated and the measured results show the RFI reduction up to 8 dB compared with the original board.