Dual-Band Frequency Selective Surface With Good Angular Stability Based on Miniaturised Periodic Triangular Structures

A novel dual-band frequency selective surface with good angular stability based on miniaturised periodic triangular structures is proposed. The triangular structure is realised by the top and bottom layers of triangular ring-shaped meander line metal layers, as well as the middle triangular ring-shaped slot metal layer. Characteristics of angular stability are analysed and validated by HFSS simulations and experimental results. To elucidate the operating principle, equivalent circuit models are first constructed for each metal layer and the overall model is derived through a series-parallel connection. The designed FSS provides two passbands, with operating frequencies ranging from 1.66 to 1.79 GHz and from 3.39 to 3.96 GHz. The electrical size has a compact unit size 0.098λ₀ × 0.098λ₀. Compared to the rectangular structure FSS with a similar metal layer, the triangular structure FSS achieves a 11.2% size reduction. The test results are in good agreement with the simulation results and show excellent angular stability at an incidence angle of 55° under different polarisation conditions. Compared to existing research results, this frequency selective surface offers significant advantages in miniaturisation, showing promising prospects for miniaturisation research and applications.