Experimental investigation on slotted Koch snowflake fractal patch rectenna

Area of Science:

• Electrical Engineering
• Antenna Design
• Energy Harvesting

Background:

• Radio frequency (RF) energy harvesting offers a sustainable power source for Internet of Things (IoT) devices but is limited by low power density.
• Existing slotted fractal antennas lack systematic optimization and focus on the critical 2 GHz band for urban RF energy harvesting.

Purpose of the Study:

• To propose and optimize a rectenna design using a Koch snowflake fractal patch antenna with rectangular slots for enhanced performance at 2 GHz.
• To investigate the impact of single versus double slot configurations on antenna performance.
• To develop and improve a rectifier circuit for efficient RF-DC power conversion.

Main Methods:

• A multivariate parametric modeling approach combined with particle swarm optimization was used to tune the fractal antenna for the 2 GHz band.
• Comparative analysis of single-slot and double-slot fractal patch antennas.
• Fabrication and experimental validation of the antenna and a half-wave rectifier circuit with impedance matching modifications.

Main Results:

• The optimized double-slot Koch snowflake fractal antenna exhibited a return loss of -26.8 dB at 2.07 GHz.
• The improved fabricated rectifier achieved over 20% RF-DC efficiency for input power ranging from -16 to 16 dBm at 1.88 GHz.
• Incorporating rectangular slots onto the fractal patch and optimizing the rectifier circuit enhanced RF power transfer.

Conclusions:

• The proposed Koch snowflake fractal antenna with optimized rectangular slots is effective for 2 GHz RF energy harvesting.
• The modified rectifier circuit demonstrates improved RF-DC conversion efficiency, making the rectenna system feasible for practical applications.
• Further optimization of antenna size and rectifier circuit simulations are needed for a fully functional rectenna system.