Topology Optimization of Broadband Antennas with FDTD

A topology optimization framework is proposed for antenna design concerning specific performance metrics that include directivity, polarization, and impedance matching. This optimization framework is implemented using the finite difference time domain (FDTD)-based adjoint variable method (AVM) and deploys its computation on Nvidia's GPU to accelerate the FDTD time marching, which is particularly suitable for broadband optimization problems. To demonstrate the capabilities of this topology optimization framework, a monopole antenna with the desired impedance matching and radiation pattern is designed and simulated. The simulation results show that the optimized antenna not only achieves low reflection within the 19.7% wideband range but also attains a high gain of 11.2 dBi in the desired direction. These operational characteristics of the antenna align well with the design specifications, with minimal time consumption compared to the existing literature.