Abstract: The development of 5G has promoted the miniaturization and integration of communication equipment，but it also leads to new electromagnetic compatibility problems.Introducing Frequency Selective Surface (FSS) into devices can effectively reduce the interference between devices.In order to overcome the weaknesses of traditional design methods，such as low efficiency，poor quality and dependence on experience，a new FSS shape optimization method was proposed herein.The proposed method presented a strategy to define the shape optimization parameters in the polar coordinate system according to the non-self-intersecting characteristics of FSS.Furthermore，based on the genetic algorithm，the method realized the intelligent search of parameters optimized by FSS and realized the intelligent optimazition of FSS unit shape in terms of the operating frequency and electromagnetic shielding performance.Three numerical examples including solid，ring and slot units have been used to verify the proposed method.The results show that the optimized FSS resonant frequency moves to 28GHz and its electromagnetic shielding performance is improved.The FSS obtained by the proposed method is stable and suitable for 5G environment.

Key words: frequency selective surface, shape optimization, genetic algorithm, 5G, electromagnetic shielding