Kavuri Kasi Annapurna Devi

Design of RF Energy Harvesting System for Energizing Low Power Devices

Electromagnetic energy harvesting holds a promising future for energizing low power electronic devices in wireless communication circuits. This article presents an RF energy harvesting system that can harvest energy from the ambient surroundings at the downlink radio frequency range of GSM-900 band. The harvesting system is aimed to provide an alternative source of energy for energizing low power devices. The system design consists of three modules: a single wideband 377› E-shaped patch antenna, a pi matching network and a 7-stage voltage doubler circuit. These three modules were fabricated on a single printed circuit board. The antenna and Pi matching network have been optimized through electromagnetic simulation software, Agilent ADS 2009 environment. The uniqueness of the system lies in the partial ground plane and the alignment of induced electric fleld for maximum current ∞ow in the antenna that maximizes the captured RF energy. The design and simulation of the voltage doubler circuit were performed using Multisim software. All the three modules were integrated and fabricated on a double sided FR 4 printed circuit board. The DC voltage obtained from the harvester system in the fleld test at an approximate distance of 50m from GSM cell tower was 2.9V. This voltage was enough to power the STLM20 temperature sensor.

Design of an RF-DC conversion circuit for energy harvesting

The design of voltage multiplier module used for energy harvesting system from ambient at downlink radio frequency range (935.2 MHz-959.8 MHz) of GSM-900 is presented. The function of this voltage multiplier circuit is to convert the RF energy signal into DC voltage that can be used to energize the low power electronic devices. The design was based on the Villard voltage multiplier circuit. A 4-stage Schottky diode voltage multiplier circuit was designed, modeled, simulated, fabricated and tested for its performance. Multisim was used for the modeling and simulation work. Simulation and practical tests were carried out for various input power levels at the specified frequency band. The RF input power levels verses the output voltages at the nodes of the Villard network were recorded. The input for the voltage multiplier module was fed through an efficient matching network from an RF energy harvesting antenna which is designed at 377 Ω impedance. For a received signal of -27dBm (1.99) μW at the antenna modules produce a DC output voltage of 2.1 V across 100 kΩ load.

Design of a 377 Ω patch antenna for ambient RF energy harvesting at downlink frequency of GSM 900

A novel 377 Ω patch antenna operating at GSM 900 downlink band for RF energy harvesting is proposed and analyzed in this paper. The designed antenna consists of a normal patch with two steps incorporated at the appropriate position to enhance its bandwidth. The antenna is designed and tested in Agilent advance design systems ADS environment and constructed on a FR4 substrate. The antenna yields an impedance bandwidth of 34.35% (325 MHz) at 946 MHz centre frequency with a return loss S11 of •29.22dB and gain of 5.2 dBi. The proposed patch antenna is suitable for ambient RF energy harvesting at downlink frequency band of GSM 900 as demonstrated by simulation and experimental results. The measured results closely agree with the simulated results.

Rectangular Stepped Patch Antenna at GSM 900 for Energy Scavenging

This paper presents a novel 377› rectangular stepped patch antenna with partial ground plane at downlink radio frequency range of GSM-900 band. Two steps are incorporated into the patch antenna, and bandwidth expansion was investigated by the currents ∞owing through the patch antenna. The antenna simulation was carried out in the ADS 2009 environment. The fabricated antenna on FR4 substrate indicates an impedance bandwidth of 32.7% (310MHz) at 947MHz centre frequency with return loss of i28:12dB. The simulated, test and fleld results of the antenna design are discussed.

A compact substrate integrated waveguide CRLH leaky-wave antenna for S-band applications

A compact beam scanning substrate integrated waveguide (SIW) composite right/left-handed (CRLH) leaky wave antenna (LWA) is presented in this paper. The dispersive behavior of the unit cell is discussed and compared with its equivalent circuit model. A SIW CRLH LWA that composed of 15-unit cells is designed and its transient e-field distribution for the left-handed, right-handed and transition frequencies are demonstrated by performing a full-wave simulation using CST microwave studio. The proposed antenna is designed to operate within the S-band frequency range exhibiting a continuous backfire to endfire beam scanning of 133 degrees from -68 degree at 2.05GHz up to +65 degree at 3.25GHz for the backward and forward wave radiations, respectively. The numerical results show a relatively high gain with a maximum gain of 8.6dBi at 2.55GHz and low cross-polarization for the entire band.