A broadband second-order bandpass frequency selective surface for microwave and millimeter wave application

Area of Science:

• Electromagnetics
• Materials Science

Background:

• Frequency Selective Surfaces (FSS) are crucial for controlling electromagnetic wave propagation.
• Achieving wideband, dual-band filtering with sharp roll-offs presents a significant design challenge.

Purpose of the Study:

• To design and validate a novel FSS with a wideband second-order bandpass response in dual microwave and millimeter wave bands.
• To enhance electromagnetic shielding efficacy through rapid transition from passband to stopband.

Main Methods:

• A three-layer metal pattern structure with integrated slot resonators (capacitive patches and inductive grids) on dielectric substrates was designed.
• An equivalent circuit model covering 5-50 GHz was developed for comprehensive frequency response analysis.
• Physical samples were fabricated and measured to validate simulation results.

Main Results:

• The FSS exhibited dual-band second-order bandpass characteristics with center frequencies at 19.42 GHz and 42.78 GHz.
• Measured -3 dB bandwidths were 4.34 GHz (17.25-21.59 GHz) and 8.54 GHz (38.51-47.05 GHz).
• Simulation and experimental results showed excellent agreement, confirming the design's efficacy.

Conclusions:

• The proposed FSS design successfully demonstrates a wideband, dual-band second-order bandpass response.
• The structure's design, incorporating specific slot resonators, enables effective electromagnetic shielding with sharp roll-offs.
• The validated design holds promise for advanced microwave and millimeter wave applications.