Genetic algorithms for the design of planar THz antenna

Abstract

This paper proposes a genetic algorithm for the design of passive components operating at THz frequencies and its experimental validation using an exemplar patch antenna. The patch antenna is based on an SU8 substrate, with a binary array describing the placement of metal “bits” replacing the conventional patch. These “bits” are constrained at 25 × 25 μm2, ensuring ease of fabrication. Optimal configurations of this array are determined using a finite-difference time-domain solver coupled to the genetic algorithm, which simulates and optimizes for maximum power collection in the frequency range of 0.10–5.0 THz. The aim was to produce an evolved patch antenna design with double the power collection efficiency across the majority of the frequency range compared to a reference, plain patch antenna of the same size. This was successful with a 5.3 dB mean improvement in simulated power collection compared to a plain reference patch. A vector network analyzer in conjunction with 0.80–1.0 THz frequency extenders was used to validate the simulation results. The antennas were arranged in pairs with variable feed length to determine the feedline attenuation and validate the simulated antenna directionality.