Terahertz reflectarray and transmitarray

Reflectarrays and transmitarrays are extremely important in the applications of terahertz (THz) technologies, as they feature merits like high gain and low cost. In this work, a reflectarray and a transmitarray are designed at 300GHz. A 32 × 50 offset-fed wideband reflectarray antenna, based on single-layer elements with a large and linear phase response, shows a fixed beam direction without frequency dispersion over a large frequency band of 0.225 ∼ 0.325THz and a gain of 30.76 ∼ 33.98dBi. The designed three-layer transmitarray element can provide 360° phase coverage with transmission coefficient over -0.9dB. Simulations show that the three-layer transmitarrays, fed by a 15-dBi horn with a focal to diameter ratio (F/D) of 0.88, achieves peak aperture efficiency of 68% with a 1-dB gain bandwidth of 23%. The transmitarrays fed by an open-ended waveguide with F/D = 0.3 are fabricated and measured for verification purpose.