  This study delves into the innovative landscape of metasurfaces, with a
particular focus on their role in achieving EM illusion (EMI) a facet of
paramount significance. The control of EM waves assumes a pivotal role in
mitigating issues such as signal degradation, interference, and reduced
communication range. Furthermore, the engineering of waves serves as a
foundational element in achieving invisibility or minimized detectability. This
survey unravels the theoretical underpinnings and practical designs of EMI
coatings, which have been harnessed to develop functional metasurfaces. EMI,
practically achieved through engineered coatings, confers a strategic advantage
by either reducing the radar cross-section of objects or creating misleading
footprints. In addition to illustrating the outstanding achievements in
reconfigurable cloaking, this study culminates in the proposal of a novel
approach, suggesting the emergence of EMI without the need for physically
coating the device to conceal and thus proposing the concept of a smart EMI
environment. This groundbreaking work opens a new way for engineers and
researchers to unlock exotic and versatile designs that build on reconfigurable
intelligent surfaces (RIS). Crucially the designs enabled by the proposed
approach, present a wide array of applications, encompassing camouflaging,
deceptive sensing, radar cognition control, and defence security, among others.
In essence, this research stands as a beacon guiding the exploration of
uncharted territories in wave control through smart EMI environments, with
profound implications spanning basic academic research in RIS through advanced
security technologies and communication systems.
