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Energy harvesting (EH) or scavenging is recognized as harvesting energy from ambient energy sources in the surrounding environment. This paper reports a literature review on radio frequency (RF) EH using different metasurface/metamaterial structures based on split-ring resonators (SRRs), electric inductive-capacitive (ELC) resonators, square-patch unit cells, square-ring unit cells, etc. The essential parameters in rectifying antenna (rectenna) design are included, such as receiving antenna efficiency, conversion efficiency, dimensions, supporting substrate properties, frequency band, and overall performance, etc. It is noted that rectenna design using conventional antennas such as microstrip antennas, monopole antennas, slot antennas, dielectric resonator antennas, etc. suffers from low power conversion efficiency with larger size. To overcome the above-mentioned constraints and enhance the conversion efficiency with smaller size, metasurface/metamaterial structures are used as EH collectors. An introduction to EH is discussed, followed by an overview of energy sources in the ambient environment. Several hypothetical and experimental studies on metasurface-based EH systems are summarized. Published version

A wide-angle and polarization-insensitive metasurface instead of traditional antenna is built as the primary ambient energy harvester. Proposed metasurface harvester can receive electromagnetic (EM) energy from wide angles and received rectified power can be combined by DC combining for EM harvesting system. The reflection coefficient, power distribution, EM harvesting efficiency, and absorption efficiency on the normal and oblique incidences are studied and presented. For a single unit cell with periodic boundary condition, simulation results exhibit that the absorption and harvesting efficiencies are more than 98 and 96%, respectively, under normal incidence at an operating frequency of 2.4 GHz. The results also show that on the oblique incidence of 0°, the maximum absorption efficiency is more than 98% and it can achieve more than 80% reception efficiency at the incidence angle of ±60°.

Electromagnetic Compatibility (EMC) engineers should self-check the antenna’s condition and parameters, including Antenna Factor (AF) and Gain, continuously, by calibrating the antenna. Therefore, several analyses have been done to compare between SAM and SSM in EMC testing lab. Based on the analysis, the antenna to be used inside a 3 m semi-anechoic chamber need to be positioned 1.5 m above the ground plane to avoid the reflection. The Antenna Factor (AF) results show a good agreement with manufacturer data. SAM is recommended as a calibration method in the semi-anechoic chamber because the percentage error is 5% which is lower compared with SSM (18%). This is due to the site imperfection in the EMC lab. The uncertainty for the EMC lab is up to ±4 dB, compared to the calibration test site where allowed uncertainty is ±1 dB. Therefore, an absorber needs to be placed between two antennas. In addition, the phase center of the reference antenna needs to take into consideration for highly accurate AF.

This experiment is about fabrication of n-type Cu2O thin film on fluorine doped thin oxide (FTO) glass by using copper acetate based solution through potentiostaticelectrodeposition. A range of deposition time was carried out from 20 to 40 minutes and the results were obtained. The other parameters such as potential deposition, bath temperature and pH value of solution were kept constant for-0.125Vvs Ag/AgCl, 60 °C and pH 6.3, respectively. It was found that the optimum deposition time for growth mechanism of n-type Cu2O thin film was 30 minutes. Structural, morphologicaland optical properties were characterized by using X-ray diffraction (XRD), Field Emission Scanning Electron Microscope (FE-SEM), and Ultraviolet and visible Absorption Spectroscopy (UV-Vis), respectively. The successfully fabrication of n-Cu2O was confirmed using PEC measurement result.

Cuprous oxide (Cu2O) is a promising material for solar cell application. Due to its various advantages over silicon material, it has been exploited extensively to be use in photovoltaic cell. Cu2O thin films were electrodeposited in sulfate-based solution. Cyclic voltammorgram (CV) measurement was used to investigate the reduction process under controlled parameters. Deposition potential of-0.1V vs. Ag/AgCl was used for the fabrication of Cu2O thin film based on the CV measurement. CV also revealed that the deposition speed was dependent on the bath pH and the temperature. X-ray diffraction (XRD) measurement, Field Emission Scanning-Electron Microscopy (FE-SEM) and Ultraviolet-visible spectroscopy (UV-Vis) were performed to characterize the deposited thin films. The n-Cu2O was successfully fabricated on FTO glass substrate with (111)-prefered orientation. Surface morphology of the thin films were observed to be in flower-like shape combination with pyramidal and triangular shape.

The performance of the PIN diode is very much depends on the chip geometry and the semiconductor material used, especially in the intrinsic region. The biasing voltage applied to the PIN diode determines the amount of holes and electrons injected into the intrinsic region and the values of its resistivity. This will give effect to the I-V performance of the PIN diode. This research studied the effects of width (and subsequently area) variations of intrinsic region of Silicon PIN diode on its I-V performance. The two dimensional structures and recipes of PIN diode are designed and simulated using Sentaurus TCAD tools. The thickness of PIN diode is kept at 40 µm while only the width is varied accordingly. Three variations of width have been chosen which are 90 µm, 80 µm, and 70 µm in order to study the impacts of width variation has on the I-V performance. Based on the simulation results, it is found that the current level is proportional to the PIN structure width.