Design of Multifunctional Reflectarray Elements Based on the Switchable Ground Plane

In this paper, we proposed a novel multifunctional reflectarray (RA) element which consists of resistor layer, switchable ground plane (SGP) layer and ground layer. The SGP consists of a frequency selective surface (FSS) and four PIN diodes. By switching the status of diodes, the SGP operates as ground or transparency to the incident waves thus the distance between the resistor layer and the ground is changed accordingly, which makes the incident power reflected or absorbed by the proposed RA element. The principle is explained and the simulated results show that the reflection coefficient is - 0.18 dB for reflector status and - 20 dB for absorber status. Moreover, the dynamic control of the reflected amplitude can be easily realized by using resistors with different resistance. The additional control of the reflected amplitude makes RA antennas more flexible and powerful in realizing complicated beam-forming applications.