A method for the bandwidth-control of terahertz low-scattering metasurfaces

By considering the reflection responses of metaunits at different frequencies, we propose an effective route to control the bandwidth of the low-scattering metasurfaces. This metasurface is composed of three kinds of units with different geometries, leading to various reflection phases as well as slight losses under the incidence of terahertz plane waves, thus inducing the destructive interference on the incoming waves. We take account of the losses in the design of the low-scattering metasurface, which is inevitable in terahertz frequency band and makes our model more accurately. Different from the previously published works, our design is manipulated over a broad spectrum instead of at single/center frequency, which is helpful to dominate the working bandwidth as desire. An optimization method is adopt to optimize the array pattern of the metasurface to attain the overall low-scattering feature. Simulation results show that the bandwidth of the metasurface is from 0.61 THz to 1.20 THz with the suppression ratio more than 8/9, which is in agreement with our prediction.