Fig. 1. Schematic of the FSS simulation structure. (a) 3D simulation structure; (b) FSS topological code

Fig. 2. Illustration of rotationally symmetric FSS construction

Fig. 3. Comparison of the polarization of the"circular"encoded FSS

Fig. 4. Comparison of simulation results of different mesh profiles

Fig. 5. Illustration of the structure of the convolutional neural network

Fig. 6. Illustration of CNN training process. (a) Loss value variation; (b) RMSE variation

Fig. 7. Comparison of prediction results and simulation results of CNN. (a)‒(d) Training set; (e)‒(h) testing set

Fig. 8. Flowchart of FSS design optimized by CNN-GA

Fig. 9. Narrowband bandpass FSS design result. (a) Optimal result; (b) topological encoding matrix

Fig. 10. Broadband bandpass FSS design result. (a) Optimal result; (b) topological encoding matrix

Fig. 11. Narrowband bandstop FSS design result. (a) Optimal result; (b) topological encoding matrix

Fig. 12. Broadband bandstop FSS design result. (a) Optimal result; (b) topological encoding matrix

Fig. 13. Dual-band narrowband bandpass FSS design result. (a) Optimal result; (b) topological encoding matrix