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arxiv: 2605.16057 · v1 · pith:FTHHCUHTnew · submitted 2026-05-15 · 📡 eess.SP

Holographic Airy Beamforming: Curved Trajectory Optimization for Blockage-Resilient Terahertz Communications

Xinyuan Hu , Boya Di , Lingyang Song This is my paper

Pith reviewed 2026-05-19 22:02 UTC · model grok-4.3

classification 📡 eess.SP
keywords Airy beamholographic surfaceterahertzblockagebeamformingtrajectory optimizationnear-field
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The pith

Reconfigurable holographic surfaces enable Airy beams with parabolic trajectories to bypass blockages and boost received power by over 10 dB in terahertz links.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

This paper shows how reconfigurable holographic surfaces can engineer wavefronts to create Airy beams that travel along curved parabolic paths in the near field. Conventional beams focus straight ahead and get blocked easily, but the curved path lets the signal go around obstacles. The key is the surface's adjustable effective aperture, which allows the starting point of the parabola to sit inside the array itself. A geometry-based algorithm then tunes the curve to deliver maximum power to a blocked user. This matters for high-frequency wireless systems because it provides a hardware-level way to improve reliability without extra digital processing or more hardware.

Core claim

The paper claims that the proposed holographic Airy beamforming scheme generates a curved beam via amplitude-only control on the RHS. The beam follows a parabolic trajectory whose offset is positioned within the aperture to maximize the received power at the location of a blocked user through geometry-based optimization.

What carries the argument

Holographic Airy beamforming based on amplitude control, which synthesizes the specific wavefront needed for parabolic propagation by adjusting the effective aperture of the RHS.

If this is right

  • The RHS achieves over 10 dB higher received power for the blocked user than traditional phase-controlled arrays.
  • The parabolic offset can be placed inside the antenna aperture to increase freedom in trajectory design.
  • Blockage in near-field terahertz communications is mitigated by choosing the beam curvature that best avoids the obstacle.
  • The compact spacing of radiation elements on the RHS enables the precise control required for Airy beam generation.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • This technique might be combined with user location sensing to dynamically update the beam trajectory as positions change.
  • Similar wavefront engineering could help in other scenarios with partial obstructions, such as indoor environments with furniture.
  • Extending the method to multiple simultaneous users would require designing several independent curved beams from the same surface.

Load-bearing premise

The reconfigurable holographic surface must provide accurate amplitude-only control to create an undistorted Airy beam following the exact desired parabolic trajectory.

What would settle it

If measurements of the generated beam show that it propagates in a straight line or along a different curve than the designed parabola, or if the power improvement is less than the claimed 10 dB in a physical test, the central performance claim would be falsified.

Figures

Figures reproduced from arXiv: 2605.16057 by Boya Di, Lingyang Song, Xinyuan Hu.

Figure 1
Figure 1. Figure 1: RHS-enabled downlink communication system in an obs [PITH_FULL_IMAGE:figures/full_fig_p002_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: Illustration of trajectory design constraints for: [PITH_FULL_IMAGE:figures/full_fig_p003_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: Comparison of normalized power distribution betwee [PITH_FULL_IMAGE:figures/full_fig_p004_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: Comparison between RHS and ULA: (a) Power received at [PITH_FULL_IMAGE:figures/full_fig_p004_4.png] view at source ↗
Figure 5
Figure 5. Figure 5: Schematic of the geometric structure of a parabolic tr [PITH_FULL_IMAGE:figures/full_fig_p005_5.png] view at source ↗
Figure 6
Figure 6. Figure 6: Power distribution of the optimized curved [PITH_FULL_IMAGE:figures/full_fig_p006_6.png] view at source ↗
read the original abstract

Terahertz communication offers vast bandwidth for high-speed transmission in the 6G networks but faces severe blockage challenges in the near-field region due to large antenna arrays. To overcome the limitation that near-field focused beams are susceptible to obstacles, wavefront engineering is leveraged to generate an Airy beam that propagates along a parabolic trajectory to circumvent blockages. In this paper, we consider the reconfigurable holographic surface (RHS) as a potential solution for such precise wavefront engineering owing to its compact radiation element spacing being much smaller than half-wavelength. We reveal that the adjustable effective aperture of the RHS allows the parabolic offset to be located within the antenna aperture, which enhances the freedom in designing Airy beam trajectories. An analog beamforming method, named the holographic Airy beamforming scheme based on amplitude control, is then proposed to generate the curved beam that propagates along the desired trajectory. To maximize the received power of a blocked user, we develop a geometry-based trajectory optimization algorithm. Simulation results validate that, compared to traditional phase-controlled arrays with analog beamforming, the RHS can leverage its adjustable effective aperture to improve the received power of the blocked user by over 10 dB.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

1 major / 2 minor

Summary. The paper proposes a holographic Airy beamforming scheme for reconfigurable holographic surfaces (RHS) in THz communications. It exploits the sub-wavelength element spacing and adjustable effective aperture of RHS to enable amplitude-only analog beamforming that generates beams propagating along parabolic trajectories, circumventing near-field blockages. A geometry-based trajectory optimization algorithm is developed to maximize received power at a blocked user, with simulations claiming over 10 dB improvement relative to traditional phase-controlled arrays with analog beamforming.

Significance. If the amplitude-only control can produce a true Airy wavefront satisfying the required parabolic trajectory and self-healing properties without uncontrolled phase errors, the approach would offer a meaningful advance in blockage-resilient near-field THz beamforming by increasing design freedom through the RHS effective aperture.

major comments (1)
  1. [Abstract and proposed scheme description] Abstract and holographic Airy beamforming scheme: The central claim that amplitude-only control on the RHS generates a true Airy beam with the desired parabolic trajectory (yielding the reported >10 dB gain) rests on an unverified assumption. Standard Airy beam solutions to the paraxial wave equation require both a cubic phase profile and amplitude envelope; restricting to amplitude modulation on sub-λ/2 elements risks introducing phase errors that prevent the beam from following the intended offset trajectory. Explicit verification (e.g., comparison of the generated field against the theoretical Airy solution or near-field propagation simulation confirming the parabolic path) is needed to secure the blockage-resilience result.
minor comments (2)
  1. [Abstract] The abstract states that 'simulation results validate' the >10 dB gain but supplies no information on the underlying channel models, blockage geometry, optimization constraints, or statistical error analysis, which limits assessment of the result's robustness.
  2. [Trajectory optimization section] Notation for the parabolic offset location and effective aperture adjustment should be defined more explicitly when first introduced to avoid ambiguity in the geometry-based optimization.

Simulated Author's Rebuttal

1 responses · 0 unresolved

We thank the referee for the constructive and insightful comments on our manuscript. We have carefully addressed the concern regarding explicit verification of the Airy beam properties and provide a point-by-point response below. The revisions strengthen the validation of the proposed holographic Airy beamforming scheme.

read point-by-point responses

  1. Referee: [Abstract and proposed scheme description] Abstract and holographic Airy beamforming scheme: The central claim that amplitude-only control on the RHS generates a true Airy beam with the desired parabolic trajectory (yielding the reported >10 dB gain) rests on an unverified assumption. Standard Airy beam solutions to the paraxial wave equation require both a cubic phase profile and amplitude envelope; restricting to amplitude modulation on sub-λ/2 elements risks introducing phase errors that prevent the beam from following the intended offset trajectory. Explicit verification (e.g., comparison of the generated field against the theoretical Airy solution or near-field propagation simulation confirming the parabolic path) is needed to secure the blockage-resilience result.

    Authors: We thank the referee for highlighting this key point. In Section III, the holographic Airy beamforming scheme is derived by mapping the required amplitude distribution onto the sub-wavelength elements of the RHS, exploiting the adjustable effective aperture to place the parabolic offset inside the physical aperture. This provides additional design freedom compared to conventional arrays. While the derivation follows from the holographic principle and the paraxial approximation, we acknowledge that explicit numerical verification of the generated field was not sufficiently detailed. In the revised manuscript, we have added near-field propagation simulations that compare the synthesized field against the theoretical Airy beam solution (including both amplitude and phase profiles) and confirm the parabolic trajectory and self-healing behavior. These results show that the dense element spacing minimizes uncontrolled phase errors, supporting the reported >10 dB gain. The new figures and discussion have been incorporated into Sections IV and V. revision: yes

Circularity Check

0 steps flagged

Derivation chain is self-contained with no circular reductions

full rationale

The paper's core derivation uses standard Airy beam propagation properties from wave optics, combined with a geometry-based optimization that places the parabolic offset inside the RHS adjustable aperture to maximize blocked-user power. No equations reduce by construction to fitted parameters renamed as predictions, no self-citations bear the central load, and the amplitude-control scheme is presented as an application of known holographic surface capabilities rather than a self-definitional loop. Simulations provide external validation of the >10 dB gain rather than defining the method itself. The approach remains independent of its own outputs.

Axiom & Free-Parameter Ledger

1 free parameters · 2 axioms · 0 invented entities

The central claim rests on standard electromagnetic assumptions for beam propagation and the ability of RHS to realize continuous amplitude control; no new physical entities are introduced, but the trajectory optimization implicitly assumes ideal near-field conditions and perfect knowledge of blocker geometry.

free parameters (1)
  • parabolic offset location
    Chosen within the antenna aperture to enhance trajectory freedom; its specific value is optimized per scenario and not derived from first principles.
axioms (2)
  • standard math Airy beam propagates along parabolic trajectory in free space under the paraxial approximation
    Invoked to justify the curved path bypassing obstacles; standard in optics but applied here to THz near-field.
  • domain assumption RHS elements can independently control amplitude with spacing much smaller than half-wavelength
    Core to the holographic beamforming scheme; enables the claimed extra design freedom.

pith-pipeline@v0.9.0 · 5742 in / 1406 out tokens · 31440 ms · 2026-05-19T22:02:11.124661+00:00 · methodology

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Reference graph

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