Compact Antenna in 3D Configuration for Rectenna Wireless Power Transmission Applications

Area of Science:

• Electrical Engineering
• Antenna Theory and Design
• Wireless Power Transmission

Background:

• Miniaturization of antennas is crucial for integrating wireless power transmission into small Internet of Things (IoT) devices.
• Existing antenna designs often face challenges in achieving reduced physical dimensions while maintaining performance.

Purpose of the Study:

• To design and characterize miniaturized antennas for wireless power transmission systems compatible with IoT devices.
• To evaluate different feeding techniques for optimal antenna performance.
• To assess the energy harvesting capabilities of the designed antennas for powering Bluetooth Low Energy sensors.

Main Methods:

• A folded short-circuited dipole antenna (T-match antenna) was modified using a 3D configuration with vertical metallic arms to reduce its size.
• Three feeding techniques were evaluated: U.FL connector, tapered balun, and microstrip transition.
• The antennas were characterized for gain and then integrated with a rectifier for RF-DC conversion efficiency measurements.

Main Results:

• A 3D T-match antenna design achieved dimensions of 56 mm × 32 mm × 10 mm at 868 MHz with a maximum gain of +1.54 dBi.
• A more compact design (40 mm × 30 mm × 10 mm) achieved a maximum gain of +1.1 dBi.
• RF-DC conversion efficiencies of 73.88% and 60.21% were measured for the two antenna designs, respectively, under specific power density and load conditions.

Conclusions:

• The proposed 3D antenna designs are suitable for miniaturized wireless power transmission systems in IoT applications.
• The T-match antenna configuration, with modifications, enables efficient energy harvesting for low-power wireless sensors.
• The study demonstrates a viable approach for developing compact antennas for powering Bluetooth Low Energy devices wirelessly.