Sub-terahertz metamaterial stickers for non-invasive fruit ripeness sensing.

Fruits and vegetables account for around a third of all food loss and waste. Post-harvest, retail and consumer losses and waste could be reduced with better ripeness assessment methods. Here we develop a sub-terahertz metamaterial sticker (called Meta-Sticker) that can be attached to a fruit to provide insights into the edible mesocarp's ripeness without cutting into the produce.

A frequency-agile retrodirective tag for large-scale sub-terahertz data backscattering.

Backscattering is a promising power-efficient communication technique providing sustainable wireless links with a low carbon footprint. This approach is a critical enabler for dense IoT networks, which are forecast to grow to 41 billion by 2025. However, existing backscatter designs are limited to the sub-6 GHz bands or narrowband operation in the millimeter-wave regime; therefore, they fail to concurrently support many interference-free low-power users.

Single-shot link discovery for terahertz wireless networks.

Of the many challenges in building a wireless network at terahertz frequencies, link discovery remains one of the most critical and least explored. In a network of mobile receivers using narrow directional beams, how do the nodes rapidly locate each other? This direction information is crucial for beam forming and steering, which are fundamental operations for maintaining link quality. As the carrier frequency increases into the terahertz range, the conventional methods used by existing networks become prohibitively time-consuming, so an alternative strategy is required.