Broadband planar slot antenna using a simple single-layer FSS stopband

In this study, the authors propose a simple structure of a new broadband planar slot antenna using a wide single-layer frequency selective surface (FSS) stopband. The proposed design is realised in two stages. First, the performances of the FSS unit cells are investigated using the finite element method of high-frequency structure simulator. Besides, the FSS structure considered as a stop-band filter in the bandwidth $\lpar 3 - 7\, {\rm GHz}\rpar $(3−7GHz) , is also validated by computer simulation technology microwave studio. Second, this FSS reflector is combined with a miniaturised wideband planar slot antenna $\lpar 29 \times 24 \times 1.57\, \; {\rm m}{\rm m}^3\rpar $(29×24×1.57mm3) . The final proposed combination is also designed, optimised, fabricated and validated by measurements. The obtained results show an operating impedance bandwidth of $86.38\percnt $86.38% $\lpar 2.92 - 7.36\, {\rm GHz}\rpar $(2.92−7.36GHz) including the Worldwide interoperability for Microwave Access band, the C band for satellite applications, and the Wireless Local Area Network band. Furthermore, the antenna provides an $8.87\, {\rm dBi}$8.87dBi measured maximum gain. Compared to the same antenna without FSS, a maximum gain enhancement of $5.53\, {\rm dBi}$5.53dBi is achieved by the proposed structure. In addition, the back lobes are reduced in the proposed structure by $ \gt 15\, {\rm dBi}$>15dBi , compared to a simple antenna. The total size of the proposed antenna, integrating the FSS, is $0.63\lambda _0 \times 0.63\lambda _0 \times 0.12\lambda _0$0.63λ0×0.63λ0×0.12λ0 .