Non-diffractive Bessel beams: novel paradigm for path-loss free near-field wireless links – LinkAll

On a daily basis, we all experience the seamless connectivity of our society. Mobile terminals as laptops, tablets, or smart phones allow us to work and interact with remote peers and machines without bothering in traveling or plugging our terminal. Wireless links are the enabling technology for the high user mobility of our society. Such high mobility results in an ever-growing data traffic reaching already dozens of exabytes per month. Current technology would not stand such pace and novel solutions are required to sustain such massive request of data rate. According to Shannon’s theorem, larger bandwidths are the only solution to boost the channel capacity of current networks. For wireless networks, large bandwidths are available in the millimetre and submillimetre part of the spectrum, justifying the current upgrading of mobile networks in such bands (e.g. xG, WiGig, etc.). Besides, future networks will be heterogeneous handling communications between users and objects located in the far-field and near-field region of the radiating devices.
Unfortunately, higher frequencies result in prohibitive propagation attenuations of the electromagnetic wave carrying the required data even for near-field links. For distances larger than few times the size of the radiating devices, the path loss will be the major cause of attenuation. Current solutions to overcome such losses for near-field links use far-field link approaches consisting in providing higher powers to high gain antennas. Such solutions are inappropriate since they do not consider the physics behind the generated losses. Besides, they do not provide a greener answer to the problem for a more responsible society preserving the environment.
LinkAll disrupts the current technology by providing a novel paradigm for next generation near-field wireless links. Non-diffractive waves and, in particular, Bessel beams will defeat the path loss. Bessel beams are exact solutions of the Helmholtz equation, which do not experience diffraction while propagating, much like propagating modes in wirelines. Near-field links based on Bessel beams will be free of path loss with an immediate impact on the link budget and operating range. Lower input powers will be required to reach remote locations with respect to the current state of the art for greener links.
LinkAll brings this new vision to light by developing a theoretical framework for the generation, propagation and reception of Bessel beams between two radiating apertures. LinkAll will unsettle the state-of-the-art for near-field links with at least three major achievements:
• Definition of the novel paradigm of near-field non-diffractive wireless links. Bessel beams will cancel the path loss faced by current solutions based on highly directive antennas for an efficient and greener link. Besides, the self-healing property of Bessel beams will provide robust wireless links.
• Synthesis of non-diffractive wireless links with space and time-modulated metasurfaces. Space and-time modulated metasurface launchers will provide a dynamic control of the non-diffractive link for moving or non-aligned users within the near field of the radiating device.
• First experimental validation of non-diffractive wireless links. A non-diffractive wireless link will be demonstrated in the 60-GHz band with at least one order of magnitude reduction of the path loss and operating range of 20 m doubling the current state-of-the-art for near-field links. Besides, the dynamic reconfiguration of the radiating device will unleash the operation of non-diffractive links to moving users.
This novel vision will be disruptive in numerous contexts from short range links in wireless personal area networks (WPAN), Kiosk downloading to future data centres and near-field chip-to-chip communications.