Desense Prediction and Mitigation from DDR Noise Source

In this paper, the dipole-moment based reciprocity method is used to perform desense prediction and mitigation from the DDR noise source to the nearby RF antenna. The noise source is from the DDR signals between the application processor and the memory IC. Radiation physics of the noise source is analyzed by understanding of the current flow. Firstly, the random nature of the DDR signals is analyzed using the measurement data. Based on the measurement data, the setup of the near field scanning is further determined. The desense prediction procedures are decomposed into two steps: the forward problem and the reverse problem. In the forward problem, the noise source is approximately regarded as a single magnetic dipole moment based on the near field scanning above this specific electronic device. In the reverse problem, the transfer function from the magnetic dipole moment to the victim antenna is obtained by measuring the H field when the victim antenna radiates. Based on the measurements of forward and reverse problem, the coupled noise to the victim antenna can be analytically estimated. The estimated RFI results are compared with direct RFI measurement to validate the dipole-moment based reciprocity method. Lastly, a few methods to mitigate the desense are also discussed.