A novel method is presented to accurately determine the operational range of an on-body, passive ultra-high-frequency (UHF) radio-frequency identification (RFID) system operating in the radiative near-field, based on its far-field radiation patterns. To this end, an efficient algorithm based on 3-D multipole expansion of the electromagnetic fields is formulated. By combining the new operator with the simulated or measured standalone far-field radiation patterns of the on-body RFID system, a comprehensive and accurate range determination is obtained. Compared with commercial software tools and measurements, we prove the accuracy and improved speed of the novel technique.

For ultra-reliable high-data-rate communication, the beyond fifth generation (B5G) and the sixth generation (6G) wireless networks will heavily rely on beamforming, with mobile users often located in the radiative near-field of large antenna systems. Therefore, a novel approach to shape both the amplitude and phase of the electric near-field of any general antenna array topology is presented. Leveraging on the active element patterns generated by each antenna port, the beam synthesis capabilities of the array are exploited through Fourier analysis and spherical mode expansions. As a proof-of-concept, two different arrays are synthesized from the same active antenna element. These arrays are used to obtain 2D near-field patterns with sharp edges and a 30 dB difference between the fields’ magnitudes inside and outside the target regions. Various validation and application examples demonstrate the full control of the radiation in every direction, yielding optimal performance for the users in the focal zones, while significantly improving the management of the power density outside of them. Moreover, the advocated algorithm is very efficient, allowing for a fast, real-time modification and shaping of the array’s radiative near-field.

A new algorithm is proposed, leveraging a 3D multipole expansions of the electromagnetic fields, to accurately determine the operational range of a radiative near-field on-body radio-frequency identification (RFID) system based on its far field radiation patterns, simulated or measured, under realistic deployment conditions. We illustrate the advocated method by an interrogating 866 MHz standard gain horn (SGH) and a passive eighth-mode substrate integrated waveguide (SIW) textile antenna deployed on an arm. The resulting algorithm is order 10 7 times faster than full-wave software, largely outperforms the range calculation via the traditional far field link method and it is capable of very accurately predicting the exchanged power.