A Smart RF Harvesting Energy Absorber Applied for Low Electrical Power Charging Unit

The high potential of various harvesting energy such as light/solar energy, heat energy, RF energy, pressure energy and mechanical vibration energy to be optimally extracted into electrical power has been considered as one best option to provide the sufficient low power charging for large varieties of electronic appliances and IoT devices. Those type of energy are available everywhere in the vicinity and of large amount quantity existed. This paper presents the numerical computation and optimization of a typical smart printed RF antenna to absorb the transmitted microwave energy from the particular vicinity places. The printed Yagi-Uda antenna structure was theoretically designed in such manner using the complementary split ring resonator (CSRR) metamaterial structure. It was examined to properly operate at around 2.4 GHz band applications. The YagiUda absorber patch structure was constructed on top of both dielectric and grounding materials of 40 mm x 90 mm x 1.6 mm physical dimension. In practice, the printed Yagi-Uda has very unique structure where the center rectangular active element placed in between two wings consisted of three parallel rectangular small patches and connected each other using RF-PIN diode. Using CST microwave studio software, each patch element of each wing could be manually set-up to operate in two conditions ON and OFF, respectively. These resemble whether the patch is connected or unconnected one to another. In the practical implementation, the electronical steering of RF-PIN diodes status will be performed by a certain controller unit placed beneath the ground plane. The main purpose of the patch steering technique is to allow the absorber device to flexibly searching the maximum RF power from the two main possible directions, arbitrarily. Various numbers of excellent numerical computing results to justify the potential properties of the smart RF-harvesting energy absorber, while it is successfully manufactured, are described in this paper. These include the matching impedance, gain and the resonance frequency variations as the impact of RF-PIN diode status alterations.