Bifunctional Meta devices based on frequency-dependent digital coding-Metasurface

Integration of multiple functionalities into the same meta-device is crucial and is the hot topic of research these days. In this article, we present frequency dependent bifunctional coding metasurface (MS). Sixteen distinct particles are designed which have independent distinct reflection phases in lower X-band and higher Ku-band. We aim to design different bifunctional coding MSs with proper selection of coding particles and proper spatial distribution of them. Three contributions are provided in this work. In the first stage, we present a coding MS which can focus the reflected waves in the lower band and defocus the same in a higher band. In the second case, a MS is de-signed which shape the reflected field in the quad beam in the lower band and provide an anomalous reflection in the higher band. In the last case, a MS is designed which can split the reflected field into two equal parts in lower band and provide an anomalous reflection in the higher band. The concept can be further extended to realize multiple functionalities in multiple bands and can be extended to realize similar functionalities in THz and optical regimes.