DESIGN OF CODING METASURFACES FOR ELECTRONIC BEAM STEERING

Abstract

Metasurface is an artificially designed material which is made of sub-wavelength meta elements arranged on a (2D) two-dimensional surface. It has created interest in researchers because of its unique electromagnetic properties which are not found in other naturally occurring materials. Programmable Metasurfaces have attracted significant attention over last few decades due to its unprecedented power to control the electromagnetic wave response on any surface. These unique properties have given new concepts like Software-Defined Metamaterials (SDM) and Intelligent Reflecting Surfaces (IRS) with multiple innovative applications. Coding Metasurfaces combined with reconfigurable elements can vigorously control the travel of electromagnetic waves and resulted in many groundbreaking applications. This thesis is mainly focused on ‘Coding Metasurfaces’ which are comprised of two forms of unit meta-atoms with reflection phase response of either 0 or 180°, which are termed as ‘0’ or ‘1’ elements and because of that it is possible to manipulate Electromagnetic waves in any desired direction and different applications based on this can be created. The new development in the field of Metasurfaces operating in different frequency bands ranging from GHz to THz are reviewed and analyzed. Literature survey of Metasurfaces concepts such as digital coding, reflection and refraction to design Metasurface are carried out for their uses in the area of electronic beam steering application. Different metasurface coding schemes are simulated in MATLAB and their numerical results are verified with theoretical results. Convolution operation on coding metasurface and space domain coding metasurface with distributed phase distribution are studied. Passive metasurface is simulated using full wave simulator CST MWS with reflection phase response of either 0 or 180°, which are termed as ‘0’ or ‘1’ elements are verified. Active coding metsurface using PIN diodes are simulated in CST MWS for dynamic beam steering and its results are verified. Study of FPGA implementation have been carried out for real time beam steering of active coding metasurface.