Modeling Plasmonic Antennas for the Millimeterwave & THz Range

Plasmonic modulator antennas have been recently shown to be able to efficiently upmix millimeter and THz waves onto optical frequencies. In this article, we introduce a theory and equivalent circuit models for designing and optimizing plasmonic modulator antennas. The proposed model aims to improve the overall understanding of the experimentally found powerful antenna field enhancement (between the impinging field at the antenna and the field within the modulator). This enhancement has already been shown to be as high as 90'000 and allows to efficiently evaluate relevant figures of merit for antenna design and optimization. The effects of antenna design parameters are presented and discussed in detail. The accuracy of the suggested models is verified by rigorous numerical computation through field simulations. As a result, we propose optimized antenna structures and their parameters, and demonstrate their field enhancement capabilities.