OAM-mode modulator for millimeter wavelength range based on the ferroelectric lens

The design of the millimeter-wave OAM-mode modulator was proposed and analyzed. The proposed OAMmode modulator is based on the electrically controllable ferroelectric lens. The ferroelectric ceramic based on a solid solution of $\mathrm{B}\mathrm{a}_{x}\mathrm{S}\mathrm{r}{}_{1-x}\mathrm{T}\mathrm{i}\mathrm{O}_{3}$ was considered as a nonlinear material; however, the proposed design is not limited by this material. Such a lens has the advantages of compact dimensions, small response time, and negligible low current in a control circuit. It was shown in this work that the concentric ring topology of the radiotransparent electrodes can provide multiple OAM mode formations by a single ferroelectric modulator. The relationship between mode purity and ring topology dimensions for the proposed modulator design was investigated. A numerical simulation of multiple OAM mode formation by the proposed modulator was performed. The proposed device can be used for modulation and/or coding information due to OAM states transferred by a single carrier millimeter wave.