Near-field Coupling Analysis Of Interconnect Structures In RF System-in-packages

With the rapid increase of the integration and complexity for radio frequency(RF)system in package(SiP),the outstanding near-field coupling between interconnections brings great challenges to the system design and optimization.Therefore,the main content in this paper is about the near-field coupling between interconnections,methods of optimization and development for RF SiP system:Firstly,theory models for near-field radiation and coupling were built to analyze the basic characteristics.And an equivalent lumped circuit model for near field coupling was constructed to calculate the capacitive and inductive coupling too.Some conclusions were verified through four amplifier circuits at different interconnections in packaging environment.Secondly,near-field equivalent simulating for system was achieved based on field-circuit cooperated simulation in board-level and a progressive optimization method was carried out further.Accuracy of these were also proved by one S-band transmitter,in which the correlation of the results between near-field simulating and scanning measurement realized over 95%.Finally,bases on the research of the near-field coupling and the optimization methods,we realized three high integrity types of dual-point-source inversion module.Comparing with a newest national similar-circuit product,ours second design has a similar isolation performance but a smaller size and higher integration level,which also proved the practicality.