Comparative Numerical Assessment of Fabrication-Aware Modelling Simplifications in PCB, Screen-Printed and Embroidered Split-Ring FSS Structures

This paper investigates how geometric and material modelling fidelity affects the simulated electromagnetic performance of a split-ring frequency selective surface (FSS) fabricated using three technologies: rigid printed circuit boards (PCBs), screen-printing, and embroidery. Within each technology, progressively simplified models are compared to identify which fabrication-related features can be omitted without substantially altering the simulated resonant response. For PCB, three model variants are considered: a full layered structure, a model without solder mask and copper fill, and a bare-copper model without dielectric layers. For screen-printing, the conductive paste and textile substrate are represented using uneven-surface and solid approximations. For embroidery, detailed-thread geometry is compared with a simplified solid representation. The effects of these modelling choices are evaluated using bandwidth, fractional bandwidth, resonance frequency, and transmission coefficient (S21) resonance depth for the fundamental transverse electric (TE) and transverse magnetic (TM) responses. The results demonstrate that modelling sensitivity is strongly technology dependent. For PCBs, the dielectric representation has the strongest influence on the overall resonance pattern. Omitting the solder mask and copper fill has a limited effect on the TE resonance frequency, but produces more noticeable changes in the TM response, demonstrating that the impact of secondary layers depends on the polarisation and the performance metric considered. Screen-printing shows moderate sensitivity, particularly in resonance depth. The largest discrepancies occur for embroidery, where thread-level simplification produces pronounced TE/TM-dependent resonance shifts and additional resonances absent from the solid model. Based on these results, comparative observations are presented regarding the suitability of different modelling representations during numerical design studies.