An orientation-independent UHF battery-less Tag for extended-range Applications

This paper describes the architecture and design criteria of a double monopole, battery-less, individually addressable RF tag for all those applications where long working distances are required (objects localization, environmental sensing, etc.). The prototype is built with off-the-shelf components in a 92x95 mm
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PCB design through low losses Rogers 4350 substrate. The proposed circuit implements two rectennas orthogonally oriented combined with matching and decoupling networks which guarantee a low-directive behavior for an orientation-independent usage of the tag. A micro-power management unit supplies the on-board ultra-low power circuitry. The node can power-up from a fully-discharge state with a 2W ERP source in the UHF 865-868 MHz band at 12 m of distance and operates at a maximum distance of 21.9 m with a sensitivity of -21 dBm.