General Method for Characterizing Switchable Elements for RIS Using De-Embedding Structures

Reconfigurable intelligent surfaces (RISs) play a significant role in 6G wireless communications by dynamically controlling the reflections of electromagnetic (EM) waves. In this work, p-i-n diodes are used to achieve the necessary phase shifts in the 1-bit RIS unit cells. In order to characterize these diodes over a frequency range from 10 to 30 GHz, de-embedding structures are carefully designed and analytically modeled. By de-embedding the test structure and matching the model parameters with empirical measurements, the behavior of p-i-n diodes within RIS unit cells is accurately determined. The developed characterization method can be easily adapted to other RF measurement tasks involving complex designs at high frequencies, thus broadening its applicability.