A dual band inset fed microstrip patch antenna designed for 2.35 GHz and 3.7 GHz Wi-Fi band applications is presented. The designed antenna has a rectangular patch with inset feed which is mounted on a FR4 substrate. The patch dimension, positioning and dimensions of the feed are determined by standard formulae. The antenna proposed performs well both in Return loss and VSWR. Return loss of -23.23 dB and -21.16 dB, VSWR of 1.20 and 1.56 were achieved for 2.35GHz and 3.7 GHz respectively. Simulation based techniques of HFSS were used to optimize the results. The simplicity in the geometry of the designed receiver antenna is attractive for its use in Radio Frequency Energy harvesting(RFEH) System. Keywords—Dual band antenna, inset fed, RF Energy Harvesting, WiFi band, WiMAX band, HFSS.

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A Dual Band Microstrip Patch Antenna for RF Energy Harvesting

This paper presents multi-band and multi-location radio frequency (RF) survey for ambient energy harvesting As an alternative to costly spectrum analyzers, the survey was conducted using software defined radio for FM (88–108 MHz), cellular band (880 MHz) and Wi-Fi band (24 GHz) The power levels at three different locations in a tier-II smart city were recorded and plotted to get information on the available ambient RF power levels A full wave voltage quadrupler circuit (2-stage Dickson rectifier) was implemented to act as a rectifier and a voltage booster Two different types of antennae were used for capturing the ambient RF signals – wire antenna and capacitive loop antenna No impedance matching circuitry was employed and the ambient RF signals were used to charge up a capacitor connected to the rectifier output Capacitive loop antenna helped in achieving a peak capacitor voltage of 16 V and outperformed the simple wire antenna which provided a peak capacitor voltage of 13 V The charged capacitor was also used to drive an LED

Multi-band multi-location RF power survey and ambient RF energy harvesting circuit

The central idea of this paper is to show the prospect of RF energy harvesting and converting the energy into DC, utilizing the reasonable power obtained, for low power device applications. The system harvests energy from various frequencies available in the spectrum band. The first part introduces some of the disadvantages of larger antenna height in KHz and higher path loss in GHz band of frequencies compared to MHz band of frequencies. Power used for the experiments is from FM band station of 90.8MHz. The second part of this paper is a voltage multiplier with a conversion ratio of four and the antenna used which is a wide band VHF antenna in order to cover frequency range from 80 to 110 MHz with a gain of 2.14dBi. Then a matching circuit to match the antenna impedance with the input impedance of the voltage multiplier is built in the third part of this paper. At the end, comparison of several power devices for load is made in this paper.

A. Devi RangaLakshmi

Papers

RF energy harvester for FM frequency band