These tiny sliding antennas are hacking the laws of physics to give you a perfect signal where your phone usually dies.
arXiv · March 18, 2026 · 2603.16472
The Takeaway
Normally, adding more antennas only gives a modest boost to signal gain, but by allowing antennas to physically move and interact with each other's fields, researchers achieved 'superdirectivity.' This allows a small array to focus a beam far more intensely than standard physics models previously thought practical.
From the abstract
In conventional antenna arrays, mutual coupling between antenna elements is often regarded as detrimental. However, under specific conditions, it can be harnessed to enhance the far-field directivity (i.e., beamforming gain). Theoretically, the directivity of an N-antenna superdirective array over the endfire direction can reach N^{2}, significantly exceeding the directivity of a traditional uncoupled array which is N over all directions. This paper investigates the potential of mutual coupling