FSS-based planar bandpass filter using strip slotted-lines

In this paper, a planar bandpass filter which is developed based on frequency selective surfaces (FSS) is proposed to be designed numerically and experimentally. Two basic patterns of FSS unit cells are posed to be established by using strip slotted-line which have asymmetric and symmetric structures, namely hexapole and octapole slotted-lines. The geometry parameter of strip slotted line in each unit cell is varied to analyze its impact to the resonant frequency shift and the characteristic response. After obtaining desired performances, the final design is then built up by constructing 10 × 10 unit cells for each structure. From numerical characterization results, it shows that the structure with hexapole slotted-line unit cell has resonant frequency of 2.46GHz with S₁₁ value of -10.76dB and S₁₂ value of -3.92dB, while the structure with octapole slotted-line unit cell has resonant frequency of 2.38GHz with S₁₁ and S₁₂ values of -19.04dB and -3.17dB, respectively. In addition, a hardware realization is also investigated for experimental characterization.