Research Projects

Energy harvesting has gained significant attention due to its potential to improve the mobility and reliability of low-power wireless devices. Electromagnetic (EM) energy harvesting in the radio frequency (RF) and microwave regimes has several advantages, including low cost, long-range power transmission capabilities, and small size. A rectifying antenna (rectanna) can be used in RF and microwave harvesting systems to convert EM waves to DC. Metasurfaces, or arrays of electrically small resonators, have proven to be potential alternatives to conventional antennas due to increased efficiency. Metamaterial resonance allows electromagnetic energy to be absorbed at specific frequencies in the electromagnetic spectrum. Metamaterial arrays outperform traditional antenna array systems due to their compact geometry and absence of destructive coupling between mutual elements. They also provide wider bandwidths due to constructive interaction between different parts. Optimal RF energy harvesting occurs when the metamaterial has a high Q-factor resonance at the same frequency as the external radiation source. Low-power energy harvesting in the RF regime is of great interest for situations where wires and batteries are impractical, such as expansive sensor networks and structural health monitoring. The recent proliferation of RF signals due to cell phones, Wi-Fi networks, and GPS has produced readily available ambient power sources for scavenging energy. To improve the performance of meta-surface EM energy harvesters, the project will focus on increasing the harvesting bandwidth, improving efficiency to close unity, using multi-polarization structures to obtain EM power regardless of wave polarization, and using multi-band geometries for collecting various frequencies from diverse radiation sources.