Dual Wideband Side-Lobe Level Suppression using Amplitude-adjustable Transmissive Metasurface

An amplitude-adjustable transmissive metasurface (MS) is proposed to suppress the side-lobe level (SLL) over two wide frequency range. The element is formed by three metal layers separated by two substrates. Two outer orthogonal metal gratings can determine the transmissive polarization while two dual-split ring resonators (DSRRs) in the middle layer achieves a high-efficiency and wideband polarization conversion. By rotating the corresponding DSRR, dual wideband amplitude modulations can be achieved, while the phases remain unchanged. As an example, a MS is designed and simulated. The amplitude of the MS in two bands both obey Taylor distribution. The simulated results indicate that the SLL is less than -22 dB in 10-18 GHz and 22-30 GHz bands. The proposed MS presents a lightweight and easily deployable flat device for stealth techniques application.