Electromagnetic Interference (EMI) Of Antenna-in-package (AiP)

In recent years, with the rapid development of wireless communication technologies, particularly the wide application of mobile communications and wireless communications, new demands for the integrated radio frequency RF transceiver system are proposed. Many RF transceiver systems of low-cost, compact, easily processing, highly integrated are designed. System in package (SiP) is a new technology proposed in1990s, which overcomes the shortcomings of other techniques. In recent years, the development and application of the system in package has become a hot research spot for the Scholars around the world.In this thesis, the electromagnetic compatibility (EMC) of the RF SiP is investigated. The near field of the differential and non-differential package antenna is simulated and analyzed using FDTD method. Base on this, two kind of via fences structures are respectively proposed, which are used to suppress the electric field inside the package cavity. Further, a method for reducing the coupling between the antenna and the strip line in the package cavity is proposed. The thesis includes the following content:In the first chapter, an introduction about the research background and significance of RF system in package is given. The research status at home and abroad is briefly described.In the second chapter, the basic electrical parameters of the antenna are firstly introduced. Then, the designed principle of microstrip antennas is briefly described. Finally, the numerical algorithms of FDTD, finite element and moments are the analyzed and compared.In the third chapter, the near field characteristics of the multi-layer package antenna are analyzed and researched. Based on the FDTD model, the distribution of the electric field inside the package cavity is simulated and a method that reduces the near field is proposed. By arranging via position reasonably, the electric field at most area of the cavity becomes uniform and less than10dB V/m. In this case, the packaged circuits can be arranged everywhere. This is helpful for circuit design. Compared with the results in reference, the number of the holes is minimized and the difficulty of the processing can be reduced. At the same time, the signal traces are also retained as much as possible.In the fourth chapter, the finite difference time domain (FDTD) 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 analyzed separately. The near field Ex and Ey are far less than Ez and approach to zero. Also, the maximum Ez appear at the edge of cavity and it is57dB 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 about20dB V/m.In the fifth chapter, the coupling between the external antenna and the circuit inside the package cavity is analyzed. By setting the structure of vie fences, this mutual coupling are excellent reduced.