The modal parameters of the printed circuit board(PCB) were calculated using finite element method

and the weaknesses of PCB were found using effective modal masses and mode shapes.According to the usual finite element modeling methods used for PCB

the finite element model was created.The natural frequencies and mode shapes were gained through modal analysis

and the global modes of PCB were found using effective modal masses.The result of modal analysis showed that the natural frequencies of PCB were low.Methods for increasing the natural frequencies in aspects of the boundary conditions and the properties of PCB were discussed.These methods can effectively improve the reliability of PCB

and also can be used in optimization design of PCB.