Many electromagnetic (EM) metamaterial inspired designs such as localized surface plasmons (LSPs), have been extensively adopted for structural health monitoring (SHM) in the recent past. These LSPs, in contact with the 'engineering structure under inspection' generate a diagnosable surface plasmons/ wave as output, when subjected to input EM waves in the near fields. This paper, an extension to recently published article in Springer, presents a procedure to analyse the sensitivity of the output surface wave. The Springer article primarily presented a novel method of transferring 'surface waves' from within the confined boundaries of the LSP sensor to the far-off distance along a guided path. In experiments, the input-EM waves and the output-surface waves were handled by a vector network analyser via a 2D robotic arm. Signals generated by LSP sensor; and, LSP sensor plus waveguide was analysed for monitoring (a) metal shell's surface profile and (b) separation of two adjacent concrete blocks. Further, in this article, the sensitivity of the output signals using a unique root mean square deviation (RMSD) index is presented. 'strain' monitoring, which is a common issue for most ACM structures. Metamaterial inspired LSP sensors are highly non-fragile, which are manufactured as bi-material composites, made of me Most of the present designs are mostly based on the generation of \(A) 'progressive wave' that travel long distances in These EM radiations in the microwave range are harmless, and their applications for ACM engineering structure can be considered without any isolation. Hence, 'near field' based LSP sensor using the