Fig. 1. Schematic diagram of the distribution of TE10 wave inner wall current and slots position

Fig. 2. Equivalent circuit with wide longitudinally series slot

Fig. 3. Schematic diagram of linear array and hourglass-shaped gap structure

Fig. 4. W-band one quarter T-shaped tree power divider

Fig. 5. The whole simulation results of power divider. (a) Second division power distribution network S parameters; (b) fourth division power distribution network S parameters

Fig. 6. 3D Stereoscopic view of array antenna

Fig. 7. Top view of broadband SIW hourglass-shaped slot array antenna

Fig. 8. Flowchart for genetic algorithm

Fig. 9. Fitness evolution curve

Fig. 10. Overall simulation results of the array. (a) Broadband antenna reflection coefficient curve; (b) radiation pattern; (c) 2D directional map; (d) electric field distribution map; (e) 3D orientation diagram

Fig. 11. Comparison diagram of impedance bandwidth corresponding to three different slots