Bandwidth Enhancement of A Planar Monopole Antenna Using CMA-ES Optimizer for B5G/6G Applications

This paper presents the use of the covariance matrix adaptation evolution strategy (CMA-ES) optimizer in helping bandwidth enhancement on a planar monopole antenna. The antenna, whose patch shape is bounded by a spline curve formed from symmetrical cycles of 14 control knots, was initially oval. Using CMA-ES, each knot’s position is then translated in the $x-, y-$, and its combined axis direction to get an improved bandwidth response due to changes in the patch shape resulting from the spline generation. By simulation, the shifting scenarios succeed in widening the antenna’s bandwidth. Furthermore, the antenna with the best bandwidth response of the three scenarios is fabricated and validated through measurement. The simulation shows that the antenna works in the range of 2.9 to 20 GHz, with a geometrical bandwidth of 224.5 %, while the measurement results show that the antenna works from 3.7 to 20 GHz or a geometrical bandwidth of 189.5 %. The agreement between the simulation and measurement results makes the proposed antenna a good candidate for further development supporting B5G/6G applications.