A compact tilted split ring multiband metamaterial absorber for energy harvesting applications

Unlike conventional power sources, green energy harvesting provides an economical way to power electronic systems for a long time. Compared to the other ambient energy sources such as solar, tidal, thermal, etc., RF energy remains unaffected by bad weather conditions or uninterrupted during night time. RF Energy Harvesting technology can absorb/convert the ambient energy into DC power with the help of an absorber/antenna and rectifying circuit called a rectenna. To improve the absorption characteristics, a metamaterial-based split ring technique is preferred. In this paper, a compact tilted split ring multiband metamaterial-based absorber is designed to resonate in the frequency bands such as LTE2350, WiFi2450, and LTE2600. The proposed absorber is presented with six split rings where the inner two rings are tilted at an angle of 45⁰. The Split rings are placed on an FR4 substrate with 1.57 mm thickness and a thin metal stripped ground plane is placed at the bottom. The simulations are conducted using High-Frequency Structure Simulator software and the parameters considered for analysis are reflection coefficient and absorption. The observed results show that the antenna resonates at frequencies 2.35 GHz, 2.45 GHz, and 2.6 GHz with a return loss of −15 dB, −28 dB, and −27 dB respectively. The radiation pattern in the E plane and H plane are also observed. Besides the multiband characteristics, the compact structure with an overall dimension of 35 mm × 35 mm × 1.67 mm signifies that the proposed Split Ring resonator metamaterial absorber is a good candidate for energy harvesting applications.