Investigation of the electric field inside differential antenna-in-package

For antenna-in-package (AiP), there will be an interaction between the antenna and packaged components and this interaction always takes place in the zone of the near field. So, it is necessary to study an electric field inside the package cavity and how to reduce it. In this study, the finite difference time domain model for the differential AiP is presented. Based on it, the distributions of the electric field inside the package cavity with the whole ground and gridded ground are analysed separately. The near fields E_X and E_Y are far less than E_Z and approach to zero. Also, the maximum E_Z appears at the edge of cavity and it is 57 dB V/m. According to this feature, a new package configuration reducing near field is presented. The measured and simulated results show that the new packaging structure can decrease the electric field inside the package cavity to about 20 dB V/m.