Design and performance of radio frequency micro energy harvesting MEMS antenna for low power electronic devices

Abstract

Radio Frequency (RF) ambient energy has become the choice as a source of green energy for energy harvesting systems due to the existence of electromagnetic wave signals that are always present in the environment without incurring cost. This RF energy is very low usually less than 190 µW. However, the antenna needs to supply sufficient power to the RF energy harvesting system to power low-power electronic devices. Therefore, the antenna needs to be designed to capture and transfer energy to the RF micro energy harvesting circuit to supply optimal power to the electronic device. The micro-strip antenna design using Micro Electro Mechanical (MEMS) fabrication technology process is the most suitable choice because of its small size, light weight and high performance. This MEMS antenna design uses Computer Simulation TechnologyMicrowave-Studio software(CST-MWS). Comparisons were made for four types of antennas namely silicon surface micromachine, silicon bulk micro-machine with air cavity, glass surface micro-machine and RT/Duroid 5880 as reference. The simulation results show that the glass surface micro-machine antenna is the smallest in size compared to the other three antennas. The return loss of this antenna is also better which is increased by 55.1% and 5.6% compared to silicon surface micro-machine antennas and conventional RT/Duroid antennas respectively. The antenna also has a large bandwidth of 117 MHz, a gain of more than 5 dB and a direction of more than 5 dBi. The glass surface micro-machine antenna has been successfully fabricated using MEMS technology which produces a transparent antenna measuring (L/W) 19 mm x 19 mm. This small sized MEMS antenna is highly sensitive and highly effective for capturing ambient RF signals and is capable of supplying sufficient power to the RF energy harvester system.