## 6 Conclusions  
In this paper, a miniaturized, polarization-insensitive, and rotation-independent FSS shield is introduced for EMI mitigation occurring at the X-band. The unit cell is composed of a fourfold symmetric convoluted geometry printed on a lossy dielectric. The FSS achieves a shielding effectiveness of 33 dB at 10 GHz frequency. Moreover, the design reveals wide angular stability up to 60\({}^{\circ}\) and exhibits identical spectral characteristics for the TE and TM polarization states. It offers a fractional rejection bandwidth of 26% for the normal and 31% for the rotated configuration at normal incidence and effectively filters out X-band signals. A prototype containing \(48\times 35\) unit cells is fabricated and tested over a wide range of incident angles for the TE and TM modes. The comparison of the results shows that the proposed FSS shield is a good candidate for selective/targeted EMI suppression  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Ref. No.** & \begin{tabular}{c} **FSS Cell** \\ **Size (\(\lambda_{0}\))** \\ \end{tabular} & \begin{tabular}{c} **Fractional** \\ **Bandwidth (\%)** \\ \end{tabular} & \begin{tabular}{c} **Oblique** \\ **Angle (\(\theta\))** \\ \end{tabular} & \
\begin{tabular}{c} **TM** \\ **Mode Stability** \\ \end{tabular} &
\begin{tabular}{c} **Salient Features** \\ \end{tabular} \\ \hline
[11] & 0.33\(\lambda_{0}\) & 21 & 60\({}^{\circ}\) & Yes &
\begin{tabular}{c} Convoluted circular loop, flexible \\ Rogers 5880, X-band \\ \end{tabular} \\ \hline
[12] & 0.09\(\lambda_{0}\) & Not reported & 60\({}^{\circ}\) & Yes &
\begin{tabular}{c} Convoluted spiral triangle cross \\ dipole, FR-4, C- and X-band \\ \end{tabular} \\ \hline
[15] & 0.24\(\lambda_{0}\) & 32 & 60\({}^{\circ}\) & No &
\begin{tabular}{c} Coupled resonators, Rogers 5880, \\ X-band, NF shielding \\ \end{tabular} \\ \hline
[16] & 0.05\(\lambda_{0}\) & 53 & 75\({}^{\circ}\) & No &
\begin{tabular}{c} Interdigitated loop element, FR-4, \\ 2.4 GHz WLAN band \\ \end{tabular} \\ \hline
[17] & 0.10\(\lambda_{0}\) & Not reported & 60\({}^{\circ}\) & No &
\begin{tabular}{c} Modified swastika, FR-4, 5 GHz \\ WLAN band \\ \end{tabular} \\ \hline
[18] & 0.16\(\lambda_{0}\) & 40 & 80\({}^{\circ}\) & No &
\begin{tabular}{c} Octagonal inductive stub loaded loop, \\ thin polyimide, X-band \\ \end{tabular} \\ \hline
[21] & 0.15\(\lambda_{0}\) & Not reported & 60\({}^{\circ}\) & No & \
\begin{tabular}{c} Dipole with folded arms, FR-4, C- \\ and X-band \\ \end{tabular} \\ \hline This work & 0.20\(\lambda_{o}\) & 26 unrotated, 31 rotated & 60\({}^{\circ}\) & Yes &
\begin{tabular}{c} Convoluted circular geometry, FR-4, \\ X-band shield operating in \\ two configurations, \\ polarization-insensitive, easy \\ fabrication \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table}
Table 3: Comparison of the proposed FSS shield with the available relevant designs.  
applications. More importantly, the FSS is scalable to other frequencies and can be utilized in two design configurations.  
Conceptualization, methodology, software, validation, formal analysis, investigation, writing, measurement, data curation: M.I. Conceptualization, resources, measurement, review and editing, and supervision: Y.H. Measurement: Y.W. Review and editing: A.M. All authors have read and agreed to the published version of the manuscript.  
This work was supported in part by the National Key Research and Development Program of China under Grant 2023 YFE0107900, in part by the National Natural Science Foundation of China under Grant 62071306, and in part by the Shenzhen Science and Technology Program under Grants JCYJ20200109113601723, JSGG20210420091805014, and JSGG20210802154203011.  
Not applicable.  
The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding author.  
The authors declare no conflicts of interest.