Controlling periodicity by Arduino device

In recent decades, with the emergence and introduction of metamaterial structures, much research has been done to apply these structures in various fields of physics, microwave engineering and optics. Metamaterials are artificial structures with exotic properties, such as negative electric permittivity and magnetic permeability at the same time in a given frequency range, or exhibit frequency stopbands where no signal can propagate. One of the limitations of metamaterial structures is low bandwidth and lack of adjustability. Regulating the structure of the metamaterials, in addition to increase the degree of freedom to control the electromagnetic behavior and scattering of the structure, also solves the problem of low bandwidth. In this dissertation, a technique to adjust the electromagnetic parameters of a substrate is proposed. In particular, media modulation can be used in controlling the radiation of leaky wave antenna or other exciting applications, such as non-reciprocal metasurfaces, etc. Nowadays, the realization of such dynamic metamaterials is one of the most challenging research area in the field of metamaterials. In this design, the “Space-time modulated” media is achieved using a tunable periodic load below a microstrip line. Tunability is obtained by connecting the periodic load of short dipoles below a microstrip line to the ground plan by mean of two diodes. By changing the external bias of the diodes, the effective permeability of the media is controlled. In this thesis, the goal is to use Model-based design is a process for designing and implementing control systems in which all stages of design, implementation, testing and evaluation of the control system are performed using a software model. As practical realization concerns, an Arduino Mega 2560 board has been used and programming has been realized using Matlab-Simulink software. Given biasing patterns and their variation in time have been implemented. Verification of the functioning has been checked by controlling a set of 24 diodes. Figures 1 and 2 report a photo of the experimental set-up for all “OFF” and all “ON” cases.