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Pyroelectric conversion can be used for thermal energy harvesting in lieu of thermoelectric conversion. In the case of human body energy harvesting, the general pyroelectric energy harvester (PEH) cannot be applied because the weak body heat can hardly penetrate the protecting layer to reach the pyroelectric material. This paper presents the realization of a honeycomb-shaped PEH (H-PEH) and a modeling method of the electrode and hole areas. The fabricated H-PEH successfully generated electrical energy using human body heat. The H-PEH with a 1:1.5 electrode-and-hole area ratio showed the best performance. To verify the human energy harvesting, we evaluated the characteristics of conventional PEH and H-PEH when body heat was used as a heat source. The maximum power of the H-PEH was 0.06 and 0.16 μW at wind velocities of 2 and 4 m s −1 , respectively. These output power values of the H-PEH were 200 and 224% larger than those of the PEH, respectively, according to the wind velocity.

A secondary coil design is reported for the stable transmission of wireless power in a misalignment situation. A coil array is applied to a secondary coil instead of typical single coil. When a misalignment occurs, the misalignment distance between an individual coil in the array and the primary coil is decreased relatively. Therefore, the sudden reduction in the inductive wireless power transmission (WPT) efficiency is mitigated. When the fabricated coil array transmits power, the maximum WPT efficiency improves by 56.45% compared with the typical single coil. The frequency band of the proposed array is wider, and this system can stably transmit power.

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