Metamaterial-Inspired Electromagnetic Encoders and Applications

Electromagnetic (or microwave) encoders are chains of inclusions (metallic, dielectric or apertures) on top of a dielectric substrate containing a certain identification (ID) code. Contrary to optical encoders, the ID code in electromagnetic encoders is obtained through microwaves. For that purpose, metamaterial-inspired transmission lines based on resonant elements constitute an interesting option, due to their small size and specific characteristics. This paper briefly reviews several strategies for the design of microwave encoders, including the readers, and points out some potential applications. The paper ends by presenting a prototype useful for motion control applications, where the encoders are implemented by screen-printing a metallic pattern (encoder chains) on a polycarbonate substrate.