Understanding 6G Near-Field Technologies


In April 2025, the 6G Near-Field Technologies White Paper 2.0 was released by RIS Tech Alliance (RISTA), just ahead of the official start of 3GPP’s 6G studies in June. With those studies now underway, the focus is shifting from early visions to practical development and standardisation. This white paper, running over 250 pages, is one of the most detailed resources available for anyone wanting an in-depth study of near-field technologies and their role in 6G.

From Far-Field to Near-Field

In earlier generations of mobile networks, from 1G through to 5G, most systems were designed based on far-field assumptions. This means signals were treated as plane waves, which works well when the transmitting antenna and the user are relatively far apart. The antennas were smaller and the operating frequencies were often below 6 GHz, so the near-field region extended only a few centimetres or metres.

With 6G, the situation changes. Antennas will become much larger and networks will use higher frequency ranges, including mid-band, millimetre wave (mmWave), and terahertz (THz) bands. These conditions extend the near-field region dramatically, turning it from a rare case into a common operating environment. Instead of thinking in terms of flat plane waves, 6G requires us to think in terms of spherical waves.

Why Near-Field Matters

In a far-field system, spatial separation of signals happens mainly in the angular domain. By moving to near-field operation, 6G systems can also exploit the depth domain. This means that multiple users who are in the same direction but at different distances from the antenna can be distinguished more effectively.

The benefits go beyond capacity. Near-field systems can focus energy more precisely, enabling higher data rates, accurate localisation and sensing, and even efficient wireless power transfer. This is made possible by technologies such as:

  • Reconfigurable Intelligent Surfaces (RIS) – programmable reflective surfaces that shape how signals propagate.
  • Extremely Large Aperture Arrays (ELAA) – antenna arrays so large that they naturally operate in near-field conditions.
  • Movable Antennas (MA) – antennas that can adjust their positions to optimise performance.
  • Cell-free architectures – where many distributed antennas cooperate without relying on traditional cell boundaries.

New Physical Effects

Because 6G deals with spherical rather than plane waves, some electromagnetic effects that were previously ignored now become important. These include:

  • Spatial non-stationarity – the signal environment varies across a large antenna array.
  • Finite-depth focusing – beams can focus energy at specific distances, not just in directions.
  • Tri-polarisation – three polarisation states instead of the conventional two.
  • Evanescent waves – short-range electromagnetic waves that carry additional information.

The white paper also discusses exotic wavefronts such as Bessel beams and Airy beams, which can self-heal or bend during propagation, opening possibilities for more robust communications.

System Design Implications

Traditional communication algorithms designed for far-field conditions may underperform in near-field environments. Equally, generic model-agnostic approaches may not fully exploit the new physics. That is why new approaches are needed in areas such as channel measurement, channel modelling, beamforming, codebook design, and beam training.

The paper explains in detail how to design systems that take advantage of the extra degrees of freedom in near-field channels, which directly influence system capacity and reliability.

Beyond Communication

Near-field effects are not only useful for faster or more reliable connections. They also open up new possibilities in:

  • Integrated Sensing and Communication (ISAC) – combining communication with radar-like sensing.
  • Wireless Power Transfer (WPT) – using focused beams to deliver energy to devices.
  • Physical Layer Security (PLS) – improving security by tightly controlling where signals are delivered.
  • On-chip wireless communications – providing wireless links within or between microchips.

Engineering and Standardisation

The white paper also looks at real-world engineering. It examines spectrum considerations, deployment strategies, prototype testing, and performance measurements. Most importantly, it addresses how near-field concepts will influence 6G standardisation. With 3GPP’s work now in progress, aligning research with global standards is crucial.

A Key Reference for 6G

The 6G Near-Field Technologies White Paper 2.0 is not just another vision document. At over 250 pages, it provides a complete framework linking theory, algorithms, system design, and engineering practice. For anyone studying or working on 6G, especially in areas such as antennas, propagation, and system architecture, it is a valuable reference that bridges academic research with practical implementation.

Near-field communication is set to become a defining feature of 6G. Understanding its principles and challenges will be essential for the next phase of wireless innovation.

There is also a paper release ceremony presentation that is available here.

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