Abstract: An RF power harvesting insert (100) for a wrist-watch, the insert comprising a dielectric substrate (102) and an antenna (104) tuned to harvest power from RF electromagnetic fields to provide a radio frequency electrical signal and comprising a track of electrically conductive material on the substrate, wherein the antenna is carried by an annular region of a first surface of the substrate.

Abstract: An RF power harvester comprising a dielectric substrate, having a first major surface and a second major surface, opposite to the first major surface; a connection for a rectifier on the first major surface; an antenna carried on the substrate for harvesting electrical power from a radio frequency electromagnetic field. The antenna comprising a first track of conductive material, carried on the first major surface and comprising a first end adjacent an edge of the substrate, a second end for connection to the rectifier, a first series of line sections between the first end and the second end and a first plurality of meanders, wherein a first line section of the series provides the first end and each subsequent line section is connected to its preceding line section by a meander and is of greater length than its preceding line section.

Abstract: An RF power harvester comprising a dielectric substrate, an antenna carried on the substrate for coupling with an RF electromagnetic field, the antenna comprising at least one track of conductive material arranged to provide at least one loop around an annular region at the edge of a first face of the substrate, wherein a signal collection gap in the loop provides an electrical connection for obtaining an RF signal from the antenna; and two signal links coupled to the gap and arranged to carry an electrical signal into a region on the substrate surrounded by the annular region.