Efficient Wireless Power Transfer to an Ultra-Miniaturized Antenna for Future Cardiac Leadless Pacemaker

An ultra-wideband antenna with an ultra-miniaturized size of only 10.66 mm3 is proposed for a leadless pacemaker. The antenna was integrated with the dummy electronics of an LP to consider the components effects. The specific absorption rates were found in the safety limits. The antenna is tested by experiments in minced pork and the measured results are found in close agreement with simulation results. To convert the received radio frequency (RF) energy into direct current (DC), a multi-section rectifier with a wideband functionality was integrated with the proposed antenna. To improve the RF-dc conversion efficiency of the rectifier, spatial power combining techniques have been employed. In these techniques, two signals (1.5 GHz and 1.52 GHz) components have been generated separately and transmitted through an ultra-wideband horn antenna. It is observed that transferring two signals improved the received dc voltage by 28.2% compared to using a single frequency.