# A Hexa-Band Metamaterial Absorber for S, C, X, and Ku Band Applications

## TL;DR

A new metamaterial absorber is designed to efficiently absorb electromagnetic waves at six different frequency bands, with potential applications in communication and stealth technologies.

## Contribution

A compact, polarization-insensitive hexa-band metamaterial absorber is introduced with high absorptivity and angular stability.

## Key findings

- The absorber achieves 97-99% absorptivity at six frequencies (2.178 to 18.689 GHz).
- The design is compact (12.5 × 12.5 mm²) and maintains performance under various polarization and incidence angles.
- Strong electromagnetic coupling among resonators enables high absorption efficiency.

## Abstract

A compact and polarization-insensitive hexa-band metamaterial absorber (MMA) is designed, fabricated, and experimentally validated for S, C, X, and Ku band applications. The proposed unit cell consists of two square rings, two hexagonal rings, and two diamond-shaped copper resonators printed on an FR-4 dielectric substrate with a thickness of 1.6 mm. The structure exhibits six distinct absorption peaks at 2.178, 5.484, 8.391, 11.811, 15.858, and 18.689 GHz, with corresponding absorptivities of 99%, 98%, 99%, 99%, 99%, and 97%, respectively. The compact unit cell of 12.5 × 12.5 mm2 achieves high absorption efficiency due to strong electromagnetic coupling among the resonators. Simulated and measured results show strong agreement, confirming the accuracy of the design. Owing to its four-fold symmetric geometry, the absorber maintains stable performance under varying polarization angles and incidence angles up to 60° for both TE and TM polarizations. The electric field, magnetic field, and surface current distributions are analyzed to explain the absorption mechanism at each resonant frequency. The proposed MMA demonstrates multiband functionality, angular stability, and high absorptivity within a simple and low-cost design, making it a promising candidate for stealth, air traffic control, and satellite communication applications.