Presentation By,

C. Renald,Einstein College of Engineering,

Tirunelveli,Tamilnadu, India

e-mail: shinushanu@yahoo.co.in

S. Sheik Mohammed, C. Renald, K. Ramasamy, and T. Shanmuganantham

The main objective of the work is to design Fractal antenna to use it as a receiving antenna in Wireless Power Transmission (WPT) system to reduce its size.

A Sierpinski carpet edge-fed microstrip patch antenna is proposed for size reduction of rectenna of WPT System.

Electric power transmission is the process in the transfer of electrical power to consumers and refers to the 'bulk' transfer of electrical power from one location to another.

A power transmission system is sometimes referred to as a "grid", which is a fully connected network of transmission lines.

Electric Power is transmitted using cable and wires

Overhead transmissionUnderground transmission

Is it possible to transmit power without wires?

YES!!!!It is possible to transmit power without cables or

wires.

Wireless Power Transmission (WPT) is the process that takes place in any system where electrical energy is transmitted from a power source to an electrical load without interconnecting wires[1].

Electric Power to

Microwave

Microwave to Electric

Power

Transmitter Receiver

Microwave in free space (air)

1964: William C. Brown demonstrated a microwave-powered model helicopter that received all the power needed for flight from a microwave beam at 2.45 GHz [2]

Intel demonstrated experiment for wirelessly powering a light bulb with 75% efficiency at a shorter distance in 2008 [3] based on inductive coupling.

Video

MicrowavePower Source

Coax-Waveguide

Adaptor

WaveguideCirculator

Tuner & Directional

Coupler

DC Bypass filter

Impedance Matching & Filter Ckt.

Microwave on free space

Receiving Antenna

Schottky Barrier Diode

Load

Transmitting Antenna

Microwave Power Source – Generates microwave power.

Coax waveguide Adaptor – Interconnects the Power source and waveguide circulator.

Waveguide circulator - Protects the microwave source from reflected power

Tuner - Matches the impedance between the transmitting antenna and the microwave source.

Directional Coupler - Separates the attenuated signals based on the direction of signal propagation.

Transmitting antenna - radiates the power uniformly through free space to the rectenna.

Rectenna is the power conversion element converting microwave incident power into DC power.

The rectenna, i.e., rectifying antenna, is one of the most important components in the application of Space solar Power Transmission and Wireless Power Transmission.

Rectenna consists of four stages such as receiving antenna, pre-rectification filter, rectifying circuit and post rectification filter.

Continued…

• Antenna - Receives the transmitted power and converts the microwave power into DC power.

• Filter circuit - Set the output impedance of a signal source equal to the rectifying circuit.

• Rectifier circuit - Consists of Schottky barrier diodes converts the received microwave power into DC power.

• Bypass Filter – Removes ripple content from the rectified DC and the smooth voltage will be provided to the load.

• Microstrip patch and dipole antennas have been used greatly in Rectenna for Wireless Power Transmission.

• Microstrip patch and dipole antennas are easy to manufacture, has a high efficiency, and easy to construct array circuit rather than any other antenna.

• Fractal antennas have become a hot topic of interest for the antenna designers because of their unique features like compact size, multiband operation etc [5].

• The size of edge fed microstrip patch antenna can be reduced for the same resonant frequency without affecting the performances, such as the return loss and radiation pattern by etching the rectangular microstrip patch as Sierpinski carpet of different iteration orders [6].

• A Sierpinski carpet edge-fed microstrip patch fractal antenna is proposed to reduce the size of antenna in the rectenna of WPT system.

• The conventional edge-fed microstrip rectangular patch antenna is designed for the center operating frequency (f0)of 2.45 GHz) and the substrate parameters (er = 4.4 and h = 1.5 mm) by following the standard procedures given in [7].

• Simulation of the whole system was accomplished with the use of commercial Method of Moments (MoM) code such as Zeland IE3DTM [8].

The return loss of –21.7954 dB at 2.45 GHz is achieved from the edge-fed microstrip patch antenna (generator) for the physical parameters L=37.525mm, W=28.525mm, Wa=22.8mm, Lp=10mm and Wp=1mm.

• The return loss of simulated antenna for first and second iteration is -25.6397dB and -18.0002dB respectively at 2.45 GHz.

Geometry of Iteration 1 Geometry of Iteration 2

Return Loss

Generator Iteration 1 Iteration 2

Smith Chart

Radiation pattern

Generator Iteration 1 Iteration 2

Elevation pattern gain display

The results shows that the antenna is resonated at the same frequency and the size of antenna is 77.81% of the generator, thus the size of antenna is reduced to 22.19% after first iteration.

Similarly, the size of antenna is 72.31% of generator with second iteration and therefore, the size reduction of 27.68% is achieved from the normal size of the generator.

The Sierpinski carpet edge fed microstrip patch fractal antenna is proposed for size reduction of rectenna of the WPT system. The antenna is designed and iterated up to second iteration by the iteration faction factor of 1/3.

The size reduction of 27.68% is achieved at second iteration without affecting other performances such as return loss and radiation pattern.

[1] www.wikipedia.com[2] W.C. Brown, J.R. Mims and N.I. Heenan, “An Experimental Microwave- Powered Helicopter”, 965 IEEE International Convention Record, Vol. 13, Part 5, pp.225-235.[3] www.tgdaily.com[4] S. Sheik Mohammed, K. Ramasamy and T. Shanmuganantham, “Wireless Power Transmission – A next generation power transmission system” 2010 International Journal of Computer Applications (0975 – 8887) Volume 1 – No. 13.[5] Werner, D. H. and S. Ganguly, “An overview of fractal antenna engineering research," IEEE Antennas and Propagation Magazine, Vol. 45, No. 1, 38{56, February 2003.[6] W.L. Chen and G.M. Wang, Small size edge-fed Sierpinski carpet microstrip patch antenna, PIERS C, Vol.3, 195-202, 2008.[7] Constantine A Balanis, “Antenna Theory, Analysis and Design” 2nd edition, John Wiley, New York, 1998.[8] www.zeland.com

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