Design of the frequency selective surface of a broadband bandpass with steep dropping

DOI:	10.11809/bqzbgcxb2023.02.038
Keywords:	broadband bandpass; frequency selective surface (FSS); miniaturization; rectangular coefficient; low insertion loss
Abstract:	In this paper, a dual polarized broadband bandpass frequency selective surface (FSS) structure using cascaded structures is designed and analyzed. The structure consists of three metal layers and two dielectric substrates, in which the top and the bottom metal layers are composed of two metal concentric rings and the middle metal layer is composed of a cross shaped metal and a metal square ring. Then, the miniaturization technology is applied to optimize the design of the FSS unit, whose final unit size is 0.165λ× 0.165λ (λ is the wavelength corresponding to the center frequency). Finally, the working mechanism of the FSS structure and the electromagnetic wave transmission characteristics of TM and TE polarization under different incident angles are analyzed by equivalent circuit and the full wave electromagnetic simulation method. The research results show that the FSS structure has a 3 dB transmission power passband width of 3.77~9.46 GHz in the range of 0°~60° incident angles, covering the C band, and the insertion loss is less than 0.5 dB in the passband of 4.8~9.5 GHz. The rectangle parameter of the two dimensional steep dropping FSS is 0.78. This FSS structure has good polarization consistency and angular stability, and good steep dropping characteristics at high frequencies, which can be applied to the design of broadband bandpass curved radomes.
Published:	2023-02-28
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