Metasurface Antenna Design for Focused Beam Applications

Metasurface antennas exploit engineered two-dimensional arrays of subwavelength elements to impose precise amplitude and phase profiles on electromagnetic waves. By tailoring the local response of each meta-atom, these surfaces can convert conventional spherical or planar wavefronts into tightly focused beams, Bessel or Gaussian modes, or multiple simultaneous foci in the near or far field. Such capability underpins advances in high-resolution imaging, wireless power transfer, point-to-point communications and non-destructive sensing. Recent design paradigms combine multi-layer stacking, reconfigurable elements and gradient-index constructs to achieve diffraction-limited spots, self-healing beams and extended focusing ranges. Practical realisations have demonstrated robust performance over wide bandwidths, dual-polarisation operation and high power-transfer efficiency, paving the way for compact, low-profile devices in terahertz, microwave and millimetre-wave regimes.

Research from Nature Portfolio

Recent studies have introduced self-healing Bessel beams at terahertz frequencies by coupling reconfigurable intelligent surfaces to conventional feeds. By synthesising a non-diffracting conical wavefront through tailored surface impedance patterns, these designs maintain beam integrity despite partial blockage and enable near-field communications over extended distances. A quantitative metric for beam quality was proposed, along with experimental validation showing superior resilience compared with Gaussian counterparts. Earlier foundational work established a broadband metamaterial lens based on gradient-index layers. This multi-layered transmitarray converts spherical emissions into quasi-Bessel beams in the near field, achieving stable focusing across a wide frequency span. Full-wave simulations and measurements confirm the ability to maintain a highly collimated beam for distances exceeding many wavelengths, demonstrating the viability of GRIN-based metasurfaces for versatile beam-shaping applications.

Metasurface Antenna Design for Focused Beam Applications publication trend

The graph below shows the total number of articles in metasurface antenna design for focused beam applications across all publications each year (not limited to Nature Index journals).

Technical terms

Metasurface: A planar assembly of subwavelength resonators designed to manipulate electromagnetic wavefronts via spatially varying impedance or phase response.

Bessel beam: A non-diffracting beam whose transverse intensity profile follows a Bessel function, exhibiting self-healing properties after encountering obstacles.

Near-field focusing: The synthesis of energy concentration at distances comparable to the aperture size, where evanescent and reactive fields contribute to focal characteristics.

Transmitarray: A frequency-selective metasurface in transmission mode, often multi-layered, that imparts a prescribed phase delay to an incident wave to achieve focusing or beam steering.

Reconfigurable intelligent surface: A dynamic metasurface whose constituent elements can be electronically tuned to alter phase or amplitude profiles in real time.

References

1. Ultrabroadband terahertz-band communications with self-healing bessel beams. Communications Engineering (2023).
2. A Broadband Bessel Beam Launcher Using Metamaterial Lens. Scientific Reports (2015).
3. Highly efficient generation of Bessel beams with polarization insensitive metasurfaces.. Optics Express (2019).
4. Design, Measurement and Analysis of Near-Field Focusing Reflective Metasurface for Dual-Polarization and Multi-Focus Wireless Power Transfer. IEEE Access (2019).
5. A Near-Field Focused Lens Based on Multilayer Transmitarray. IEEE Access (2025).