Design of Broadband Dual-Polarized Meta-Atoms for Reflecting Meta-Surfaces Using Characteristic Modes

In the recent years meta-surfaces became a matter of interest in the design of electromagnetic applications. Especially reflecting meta-surfaces gain a lot of attention related to the development of the future 6 G mobile communication standard. One key technology therein is the reconfigurable intelligent surface (RIS). In the frequency range 6 GHz - 9 GHZ, RIS are usually realized in printed circuit board technology. Therefore, electrically small patches, so called meta-atoms are placed over a ground plane. Thus, the impinging wave is modulated to reflect into a predefined direction. Often described as reflection beyond Snell’s law. A periodically repeating group of meta-atoms is called unit cell. In previous works the application of Characteristic Modes to the unit cell design for reflecting meta-surfaces has been shown [1–2]. Whereas the design of the meta-atom is considered superficially in most literature. In order to achieve intuitive insight into the entire design process the application of the Characteristic Mode theory for the meta-atom design is discussed.