The Journal of China Universities of Posts and Telecommunications ›› 2024, Vol. 31 ›› Issue (1): 57-63.doi: 10.19682/j.cnki.1005-8885.2024.2006

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Study on high-order frequency selective surface with interdigital capacitance loading

Zheng Guangming, Zhou Tianle, Lu Haiwei, Long Yifei, Bai Jing   

  1. School of Electronics Engineering of Xi'an University of Posts and Telecommunications, Xi'an 710121, China
  • Received:2022-01-11 Revised:2024-01-27 Accepted:2024-02-22 Online:2024-02-29 Published:2024-02-29
  • Contact: Corresponding author: Zheng Guangming, E-mail: gmzheng1224@163.com E-mail:gmzheng1224@163.com
  • Supported by:
    This work was financially supported by the 2023 Shaanxi College Students Innovation and Entrepreneur-Ship Training Program Project (S202311664066), and supported by the Xi'an Science and Technology Association Youth Talent Lifting Program Project (959202313012).

Abstract: The application of frequency selection surfaces (FSSs) is limited by large area, narrow bandwidth, low stopband inhibition and large ripple in the passband. A method for designing high-order wide band miniaturized-element frequency selective surface (MEFSS) with capacitance loading is introduced. The proposed structure is composed of multiply sub-wavelength interdigital capacitance layer, sub-wavelength inductive wire grids separated by dielectric substrates. A simple equivalent circuit model, composed of short transmission lines coupled together with shunt inductors and capacitors, is presented for this structure. Using the equivalent circuit model and electromagnetic (EM) model, an analytical synthesis procedure is developed that can be used to synthesize the MEFSS from its desired system-level performance indicators such as the center frequency of operation, bandwidth and stopband inhibition. Using this synthesis procedure, a prototype of the proposed MEFSS with a third-order bandpass response, center frequency of 2.75 GHz, fractional bandwidth of 8% is designed, fabricated, and measured. The measurement results confirm the theoretical predictions and the design procedure of the structure and demonstrate that the proposed MEFSS has a stable frequency response with respect to the angle of incidence of the EM wave in the ±30° range incidence, and the in-band return loss is greater than 18 dB, and the rejection in the stopband is greater than 25 dB at the frequency of 3.2 GHz.

Key words: frequency selective surface, high-order bandpass filter, periodic structures, interdigital capacitance