Single-layer quad-band FSR with enhanced angular stability for S- and C-band applications

Area of Science:

• Electromagnetic compatibility
• Metamaterials and artificial intelligence

Background:

• Frequency-selective surfaces (FSS) and absorbers are crucial for electromagnetic wave manipulation.
• Developing multifunctional devices with both absorption and transmission capabilities presents a significant challenge.

Purpose of the Study:

• To propose and demonstrate a single-layer, polarization-insensitive frequency-selective rasorber (FSR) with quad-band absorption.
• To achieve a multifunctional device integrating absorption and selective transmission for electromagnetic applications.

Main Methods:

• Integration of a quad-band resonant absorber and a single bandpass FSS on opposite sides of an FR4 substrate.
• Analysis using an equivalent circuit model and effective-medium theory.
• Fabrication and measurement of a prototype.

Main Results:

• Achieved over 90% absorption at 2.14, 2.88, 6.02, and 7.32 GHz.
• Demonstrated a transmission band at 4.54 GHz with low insertion loss.
• Exhibited enhanced angular stability up to 50° for both TE and TM polarizations.

Conclusions:

• The proposed single-layer FSR exhibits effective quad-band absorption and single-band transmission.
• The design shows polarization insensitivity and good angular stability.
• The device is suitable for radar cross-section reduction, EMI mitigation, and multi-functional radome applications.