# How 6G Beamforming Can Focus a Signal at a Point *Large antenna arrays can use wavefront curvature to target both direction and distance, but the hardware trade-offs are still unsettled.* By [Tech Tab](https://paragraph.com/@tech-tab) ยท 2026-08-05 wireless, 6g, engineering --- Most cellular antennas aim a radio beam in a direction. A phone somewhere along that path can receive the signal, much as an object in a flashlight beam catches light. A proposed technique for 6G is more selective. It can concentrate radio energy around a particular point, defined by both direction and distance. This is called near-field beamforming, or beam focusing. The name does not mean the phone must be almost touching the antenna. With the very large antenna arrays being studied for 6G, the relevant near field can extend for tens or even hundreds of metres. A paper published in Scientific Reports on August 5 compares several ways to build such a system. Its most useful contribution is not a declaration of one winner. It shows why the best architecture changes with distance, bandwidth and the cost of the radio hardware. When a flat wave is no longer flat ---------------------------------- Radio waves spread outward in curved fronts. Far enough from an antenna array, however, a small section of that curve looks nearly flat. Current beamforming systems usually exploit this approximation. They adjust the phase, or timing position, of the signal at each antenna element so the waves reinforce one another in a chosen direction. The approximation becomes less accurate as the antenna panel grows, the wavelength shrinks or the receiver moves closer. The boundary is commonly described by the Rayleigh distance. It grows with the square of the array's physical aperture and decreases with wavelength. In other words, a larger array or higher radio frequency pushes the boundary farther away. Within that boundary, each part of the array is measurably farther from the receiver than another. The incoming or outgoing wavefront must be treated as spherical rather than planar. Those path-length differences encode two coordinates. The system can infer and control angle, as before, but also distance. To focus a transmission, the array calculates the path from every antenna element to the target point. It then applies a delay or phase adjustment so the many copies of the signal arrive together there. Away from that focal point, they align less neatly. The IEEE Communications Society compares the effect to a controllable convex lens. This extra distance dimension could let a base station serve two devices that sit along nearly the same line but at different ranges. Research published this year on volumetric beam focusing goes further, exploring ways to concentrate energy inside a compact three-dimensional region rather than across an entire direction. Why the array needs two control layers -------------------------------------- The most flexible design would give every antenna element its own complete radio-frequency chain, including conversion and digital processing. That is fully digital beamforming. It offers fine control, but thousands of chains would consume substantial power and add cost. Hybrid beamforming divides the work. An analog layer uses phase shifters or true-time-delay components to coordinate many antenna elements. A smaller number of digital radio chains then separates users and data streams. This retains much of the spatial control without duplicating expensive electronics behind every element. The new Scientific Reports study compares fully digital processing with several hybrid layouts. In a fully connected layout, every radio chain can influence every antenna. A sub-connected design assigns each chain to a smaller group. Delay-phase precoding combines phase shifters with time delays, which matters because a phase setting that focuses one frequency may misalign another across a wide channel. The paper also evaluates reconfigurable intelligent surfaces. These are electronically controlled panels that redirect radio waves rather than generating the main signal themselves. In the study's simulations, the surface-assisted method had the highest modeled energy efficiency. Delay-phase processing was the more consistently adaptable option across the tested distances and bandwidths. Those results describe a model, not a field deployment. The reported rankings depend on the power assumptions, channel conditions and selected configurations. The article does not show a commercial 6G base station serving moving phones. The difficult part is keeping the focus --------------------------------------- A focused link requires an accurate description of the channel between the array and the device. In the far field, a network can search a codebook of directions. Near-field training must search direction and distance, increasing measurement and signaling overhead. Movement makes that harder. A narrow focal region is useful only if the network can estimate position, update the beam and calibrate a large array quickly enough. Reflections and blockage add more paths to the calculation. Wide bandwidth creates another problem called beam split. Different frequencies can focus at different locations when the hardware applies the same phase pattern across the band. True-time-delay components can reduce the effect, but they add complexity and power loss of their own. Standardization is also incomplete. The IEEE overview notes that established 5G channel models largely assume far-field propagation, although 3GPP work is extending models for higher bands and near-field behavior. Real measurements, shared channel data and hardware prototypes are still needed to determine where the theoretical gain survives practical constraints. The important shift is conceptual. A large array is not merely a louder or narrower antenna. Once wavefront curvature becomes useful information, the network can treat depth as a communications resource. The engineering question for 6G is how much hardware and computation that extra dimension is worth. Sources ------- * [Scientific Reports: Reconfigurable hybrid beamforming across near- and quasi-far-field regimes](https://www.nature.com/articles/s41598-026-64983-x) * [IEEE Communications Society: Near-field communications for 6G](https://www.comsoc.org/publications/ctn/near-field-communications-6g-ten-key-issues) * [IEEE Communications Magazine: Near-field MIMO communications for 6G](https://doi.org/10.1109/MCOM.004.2200136) * [npj Wireless Technology: Volumetric beam focusing in extreme MIMO](https://www.nature.com/articles/s44459-026-00026-1) * [Nokia: Communications in the 6G era](https://www.nokia.com/asset/f/207766/) --- *Originally published on [Tech Tab](https://paragraph.com/@tech-tab/how-6g-beamforming-can-focus-a-signal-at-a-point)*