Broadband Planar Log-Periodic Dipole Array Antenna Based RF-Energy Harvesting System

What is it about?

In this paper, a low cost planar log periodic dipole array antenna has been described using triangular dipole elements for broadband RF energy harvesting applications. The antenna measured bandwidth for VSWR ≤ 2 is from 570 to 2750 MHz (1:4.8), which covers all the cellular bands. The radiation pattern is uniform over the entire frequency range. The measured gain is 7.2dBi with less than ±0.5 dB variation over the entire bandwidth. A Schottky diode based voltage doubler rectifier is used to convert RF energy to DC voltage. A broadband impedance matching network using an exponentially tapered microstrip line between log periodic antenna and rectifier has been designed. At a distance of 25m from the cell tower, a voltage of 1.7 V was obtained using the developed broadband RF energy harvesting system across a load of 4.7 kΩ. A voltage of 3V was obtained across the same load while initiating a call from a cell phone.

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Why is it important?

The antenna finds application for RF energy harvesting, portable direction finding and monitoring the radiations from cell towers using a spectrum analyzer.