Expedited Frequency Scaling of Circular Polarization Antennas by Inverse and Forward Surrogates

Thepaper demonstrates utilization of inverse and forward surrogate models for accelerated dimension scaling of circular polarization antennas. The problem at hand is to find optimum dimensions of the antenna re-designed for a particular operating frequency, which includes maximization of the realized gain in the broadside direction as well as ensuring acceptable matching and axial ratio bandwidths. According to the proposed methodology, the initial design is found using a fast inverse surrogate model established using several reference designs optimized for selected operating frequencies. Subsequently, design correction is realized using a forward surrogate of the antenna response Jacobians. Overall, the dimension scaling process is achieved at a very low cost of a few full-wave electromagnetic (EM) analyses of the structure at hand. Our technique is demonstrated using a two-point-input circularly polarized patch antenna excited through a hybrid coupler. The antenna is redesigned within the operating frequency range of 4.5 GHz to 6.5 GHz.