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This paper deals with glass surface micromachined antenna of RF energy harvesting for wireless sensor node applications. The research aims to provide a system based on a new integrated RF energy harvester circuitry using a transparent receiving antenna by micromachining process. The energy harvester system is studied using CST-MWS software by Pyrex glass as the antenna substrate having dielectric constant ɛr = 4.6. Besides, PSpice and Cadence analyze the DC output solutions. The fabrication of the micromachined antenna based on metal patterning of the radiator patch and metal sputtering on the top and bottom of the glass surface, respectively. The analysis of the wave propagation of the antenna shows good agreement between the simulation solutions and experimental validations. It is present that the antenna achieved a maximum gain of > 4 dB, reflection coefficient (S11) 100 MHz, omnidirectional radiation pattern and VSWR ratio

This paper describes the design and fabrication of MEMS patch antenna fabricated on glass substrate for RF energy harvester system. The idea was derived from the great property of glass, such as transparency, high mechanical surface strength and good dielectric property that is predicted to replace the conventional and silicon semiconductor material as the substrate for an RF energy capture. Aim of the study is to develop MEMS patch antenna that should be compatible with 180 nm CMOS process. The antenna device consists of a substrate, slotted petal conductor, ground plane and impedance matched output slot. The substrate is made of pyrex glass and fabricated using a surface micromachine process technique. The fabricated device is then measured in an anechoic chamber and compared with other antenna made of silicon and standard conventional antenna substrate. The results show that the patch antenna on glass performs similar to the conventional antenna fabricated on RT/Duroid that show very promising alternative substrate material for an energy harvester system where size, weight, cost, performance, ease of installation and fabrication are constrains.

The paper deals with the growing interest of energy harvesting systems due to great development in many new emerging technologies in electronics and telecommunication. The research focuses particularly about rectenna element comprises of antenna, impedance matching and rectifier. The rectenna is applied under Micro-Electromechanical-System (MEMS) technology design use in Radio Frequency (RF) energy harvester. MEMS is a technology of miniaturization that has been mostly adopted from integrated circuit industry together on a chip that are made using micro fabrication technique and applied for not only electrical systems. RF ambient source is considered over other ambient sources because RF can be broadcasted by various wireless systems in unlicensed frequency bands. However, the amount of energy captured from the ambient RF is extremely low which need improvements and more Direct Current (DC) voltage generated from RF energy harvester. For this motivation, a dual band MEMS rectenna is proposed for maximizing the efficiency. Power Management Unit (PMU) is interposed between MEMS rectenna and a load. The system is equipped with temporary energy storage and voltage regulator to produce optimum output voltage. The paper proposes a system that is designed and simulated using PSpice software and modeled in Mentor Graphic. The stated result from RF MEMS energy harvester is to provide functional conversion efficiency and reliable energy harvesting system to reach 1.5-3.0 V output voltage for operating frequency at 1.9 and 2.45 GHz from RF input power at -20 dBm with reveal approximately 100% improvement over other existing designs. The conceptual design can be the platform for innovative developments in recent technologies to achieve wireless transmission powered only by RF MEMS energy harvester.

This paper presents a comparative study of Si based micromachined and Si based regular rectangular microstrip patch antenna operating at 5 GHz (unlicensed Industrial, Scientific and Medical (ISM) band) frequency for radio frequency (RF) energy harvester. The work is aimed to find alternative substrate modes for integrating the antenna with the harvester circuitry design. The micromachined antenna is based on a modification of silicon (Si) wafer using micromachining technology. In this design, the Si material is etched horizontally underneath the printed patch to produce a cavity consisting of an air-filled and the Si structure in a defined thickness ratio. The air cavity synthesizes a low effective dielectric constant around the radiating patch and improving the radiation gain. The design has been simulated and analysis in CST Microwave Studio software (CST MWS). The results validate superior parameter of the micromachined over regular antenna where the gain has increased by 166.2% while the −10 dB bandwidth performed. Thus the idea of micromachining is relatively useful for designing an efficient radiator and broad bandwidth antenna for integrated RF energy harvester applications.

The growth innovation and versatility in wireless energy harvester have attracted an attention on the development of antennas. This paper presents microstrip patch antenna design of a dual-band radio frequency (RF) energy harvester system for self-powered devices. The antenna is designed using a slot-coupled structure to realize for dual microwave bands operation. By using an optimization parameter of 50Ω feed point on microstrip line, the proposed patch antenna has achieved good impedance matching. Parameter design of the feed point with the optimal extension length, ΔL improves the performance at targeted resonating frequencies. COMSOL Multiphysics 5.1 electromagnetic package is utilized for the simulation and analysis process. The proposed antenna provides good performance parameter in terms of radiation pattern and return loss. The simulated results indicate satisfactory return loss performance of −31.867 dB and −24.437 dB in the dual narrowband resonance frequencies at 1.9GHz and 2.45GHz respectively. This property of results can be employed in rectifier of RF energy harvester system.

This paper presents a highly efficient rectenna of RF energy harvesting systems operating at 1.8 GHz and 2.5 GHz bands for battery-less sensor application. The antenna is design by CST-MWS. The Schottky diode used for rectifying circuit is HSMS 286B in which designed by Agilent ADS. The key finding of the paper is that the simulated DC output voltage of the rectenna is 1.35 V for low input power of -25 dBm at a high resistance load of 1M Ω. Correspondingly, the RF-DC conversion efficiency of the rectification process is 59.51% and 45.75% at 1.8 GHz and 2.5 GHz, which are high efficiency and much better compared to literature respectively. The rectenna is capable to produce 1.8 V from an input power of -20 dBm. Thus, the proposed RF energy harvesting system offers a promising solution designed for efficient functionality at a low power level of RF energy in the dual band.

This paper presents a comparative performance of the antennas fabricated using bulk micromachining and surface micromachining process. The dielectric permittivity of crystal silicon (Si) and glass are ɛr = 11.9 and ɛr = 4.7, respectively are considered in the substrates comparison studied. The research aims to discover the best antenna performance by alternative micromachining modes for integrating with the RF harvester printed circuit design. Here, the study on micromachining process method involves the simulation study of three different structures and materials, such as Si with air gap, Si surface and glass surface based antenna. These antennas have been modelled using CST-MWS software. The micromachined antennas have been optimized operating at 5 GHz band. The parameters such as S-parameter, -10 dB bandwidth, radiation pattern, gain, directivity and VSWR are evaluated. The outcomes validate good characteristic of glass based surface micromachined antenna over the Si based for both bulk micromachined and surface micromachined antenna. The results show that the Si surface micromachined antenna is not able to reach the requirement for RF antenna specification, however, it is improved by creating the air cavity. Furthermore, the use of glass substrate has increased the antenna gain by 5.34% and the -10 dB bandwidth increased by 72.86% compared to the Si with air cavity. The glass based antenna dimension is reduced by 9.09% and 44.93% compared to Si bulk micromachined and Si surface micromachined antenna, respectively. Thus, the characteristics of the glass surface micromachined antenna are relatively appropriate for highly efficient RF energy harvester application

Selection of energy source depends on several factors, including energy availability, economic and power requirements. Hydro power is more cost effective than any other form of renewable power. This paper studies the performance of various stator designs in a micro hydro generator. The generator generates energy using rainwater that falls from the roof drainage system. The rainwater flows through the drainage hits the turbine and generates output power less than 500 W. This entire system consists of two main parts; mechanical and electrical. This paper focuses on the factors of designing micro hydro generator; the rotor and stator which the performance of each design of the stator is tested. The design factors to be considered in the stator are the copper wire size and number of turns of copper wire with 8 poles of magnet placed at the rotor. The designed generator produces output power in AC, then it is converted into DC using rectifier. The output power of this generator must be able to withstand over 2.5 W with 8 V DC voltage and 250 mA DC current at the highest rotation speed; 900 rpm. However, the power produced depending on capacity of rainwater as well as the pressure of the rainwater that runs from the roof drainage system that hits the turbine.