Renewable energy sources from the earth constitute another option apart from the available ones for wellspring of energy for economizing on cost of power supply. The energy obtained from ambient sources is called energy harvesting. Energy-harvesting low-power systems have acquired a remarkable consideration as a viable hotspot for expanding both energy efficiency and spectral efficiency. Radio frequency (RF) energy harvesting from ambient source is a promising technique for fulfilling the irreplaceable power prerequisites for powering the low-power devices. Hence, it requires the development of an antenna for harvesting RF energy. In this paper, a coplanar waveguide (CPW) antenna has been designed and fabricated using FR4 lossy substrate. This CPW antenna covers frequency bands from the most important RF patrons (GSM 900, GSM 1800, 3G, and Wi-Fi) within the frequency range from (0.58 to 3 GHz) with a percentage fractional bandwidth of 116% with the center frequency of 1.65 GHz. The fabricated antenna then has been experimentally validated at SSN College of Engineering campus. The effects on the RF power density level for CPW antenna are examined by statistical approach known as Taguchi method. The L9 and L8 orthogonal arrays and analysis of variance are implemented to analyze the execution qualities. The CPW antenna control factors are distance, time, and number of receivers. Then, statistical test (P) are used to determine the significant factors on RF power density. KEYWORDSANOVA, CPW antenna, RF energy harvesting, spectral survey, Taguchi orthogonal array | INTRODUCTIONThe enormous growth in communication networks has triggered persistent expansion of the need for energy supply, leading to a battery exhaustion issue for wireless communication devices. 1 Research work has been conducted recently to increase energy from ambient sources, which is an alternate option for maintaining a sustainable energy supply instead of rechargeable or replaceable batteries. 2 Energy harvesting has been proposed for accomplishing this and ensuring unlimited energy supply to electronic systems and saving energy consumption. 3,4 Hence, energy harvesting grasps energy from the ambient environment and stores them for future use. There are different types of energy harvesting such as thermal, solar, and radio frequency (RF). Energy harvesting from electromagnetic (EM) radiation has huge consideration because of wireless communications networks. 5 Electromagnetic radiations from the far-field applications have emerged in the form of radio frequency and can be collected by aerial, which converts the radio waves into electric power using rectifier circuits. 6 This paper envisages the usage of harvesting arising from the availability of frequency bands such as Wi-Fi routers, cell phones, and laptops. Cognitive radio can be powered from RF ambient sources, which improve the spectrum efficiency and energy efficiency. 6 Use of the RF signal and the distance between an RF energy source can help harvesting RF energy. First, the purpose of the ...

Nowadays, radiofrequency (RF) is a vital component of harvesting RF energy from the ambient environment to power ultra‐low‐power applications in wireless communication. This article presents an RF energy harvesting system for a frequency range of (0.58–3 GHz) to harvest RF energy from the ambient source. The system's design consists of four major modules: a coplanar waveguide antenna (CPW), a bandpass filter (BF), an L‐type impedance matching network, and a four‐stage Villard voltage multiplier (VM) circuit. First, A CPW antenna is designed suitably to harvest RF energy from GSM 900/1800, 3G, and Wi‐Fi frequency bands. Next, a BF is designed and simulated in Agilent advanced design system software for the same frequency range to attenuate the RF signals that are not in this specific frequency range. Then, an RF power conditioning circuit prototype comprising an L‐type impedance matching network and a four‐stage Villard VM circuit was integrated and fabricated on an FR4 substrate. The four‐stage rectifier circuit is designed to convert the RF signal into DC output voltage and maximize the output voltage. The performance of the RF energy harvesting system is validated through simulation and measured results. All the RF energy harvesting system elements have been connected, and the prototype is tested at various indoor and outdoor locations of Sri Sivasubramaniya College of Engineering, Chennai, India. It is observed that the prototype system can harvest energy from input power levels as low as −30 dBm. The simulated results of the RF energy harvesting system achieve an output voltage of 2.5 V with a maximum efficiency of 62.5%. The harvested output voltage at a distance of 100 m from the RF cell tower at the indoor location is 59.5 mV and at the outdoor location 271.6 mV. The harvested output voltage is used to energies the ultra‐low‐power applications. Finally, the performance of the RF energy harvesting system is analyzed by statistical techniques. The two types of analysis are Taguchi's method and analysis of variance. The RF energy harvester impact factors are VM and BF. A statistical test (P) is used to determine the significant factors on the RF output voltage.

Radio Frequency (RF) plays a vital role nowadays in harvesting RF Energy from the ambient source. An antenna is required to harvest RF energy and solve the spectrum underutilization problem for the Cognitive Radio (CR) system. This paper presents an optimization of a reconfigurable Coplanar Waveguide Antenna (CPW), which harvests RF energy and is also used for sensing and communication purposes. The performance metrics of the proposed antenna are gain, radiation efficiency, front-back ratio (FBR) and group delay. First, the optimized CPW antenna (sensing antenna) is designed and fabricated in the FR4 substrate for the wideband frequency range of (0.25–3 GHz) with the fractional bandwidth percentage of 175%. The gain of the proposed optimized CPW antenna for different frequency band is: DTV band (UHF-0.47 GHz)-3.327 dBi, GSM 900-2.39 dBi, GSM 1800-3.42 dBi, 3G-3.227 dBi, and Wi-Fi-3.21 dBi. The average gain of the optimized CPW antenna for the frequency range of (0.25–3 GHz) is 3.11 dBi, and the maximum radiation efficiency of the antenna is 91.05%. Next, the optimized CPW antenna is reconfigurable, and it can be reconfigured for a specific frequency band using a PIN diode switch. When the PIN diode switch is in ON state, the antenna acts as a reconfigurable antenna (communicating antenna), and it is operated for the specific frequency band of (0.47 GHz-DTV [UHF] band), (0.9, 1.8, and 2.1 GHz-mobile bands), and (2.4 GHz-Wi-Fi bands). The maximum gain of the optimized frequency reconfigurable CPW antenna is 3.61 dBi, and the radiation efficiency is 92.5%. In the OFF state, the antenna acts as a sensing antenna, and it operates at a wideband frequency range of (0.25–3 GHz). Finally, the prototype of a four-stage Villard voltage multiplier RF-dc conversion circuit using an adjustable impedance matching network is proposed for powering the cognitive radio applications.