Via: Study Finds:

Results show people are actually the best medium for amplifying the coil’s ability to collect leaked RF energy. Attaching the coil to a person collected up to 10 times more energy than just using a bare coil.

Based on these results, the researchers created an inexpensive, wearable device called the “Bracelet+ ,” which people can wear on their upper forearm. Study authors note they can even modify it to work as a ring, belt, anklet, or necklace — although a bracelet seemed to work best for harvesting power.