Inverse-Designed Metasurface-Loaded Antennas Enabled by Efficient Modal Expansion Methods and Global Optimization Algorithms

In this paper, an effective inverse-design approach is applied to metasurface-loaded antennas that is based on using efficient modal expansion methods (MEM) and robust optimization algorithms. Two types of antennas are considered – suspended patch antennas and a short backfire antenna (SBFA) loaded with metasurfaces. Both antenna designs are analyzed, optimized, fabricated, and validated experimentally. The measured results show that the suspended patch antenna realizes two operational bands covering 1.62 – 2.73 GHz and 4.52 – 6.52 GHz. A tunable version of the antenna is enabled by integrating varactors in the metasurface. For the SBFA, an enhanced aperture efficiency is accomplished with higher than 83% within a 35.3% bandwidth. For both examples, the MEM is demonstrated to be a highly efficiency method for analysis, which can accelerate the design process when it is coupled with optimization algorithms.