5.8 GHz High-Efficiency RF-DC Converter Based on Common-Ground Multiple-Stack Structure

Area of Science:

• Electrical Engineering
• Radio Frequency Engineering
• Power Electronics

Background:

• Efficient conversion of radio frequency (RF) energy to direct current (DC) is crucial for wireless power transfer and energy harvesting.
• Existing RF-DC converters often face challenges in achieving high efficiency and output voltage simultaneously, especially in multi-stack configurations.
• Integrating multiple RF-DC converter stacks while maintaining RF and DC ground isolation is a significant design hurdle.

Purpose of the Study:

• To propose and validate a novel RF isolation network (RFIN) for a common-ground, multiple-stack RF-DC converter.
• To enhance conversion efficiency and output voltage in RF-DC conversion systems.
• To demonstrate the feasibility of a compact, single-layer PCB implementation for high-performance RF-DC converters.

Main Methods:

• Design and implementation of a 5.8 GHz, 4-stack RF-DC converter utilizing a class-F voltage doubler for each stack.
• Development of a unique RF isolation network (RFIN) enabling combined DC output from multiple stacks without compromising RF ground integrity.
• Fabrication on a single-layer printed circuit board (PCB) with a common ground plane.
• Performance evaluation through comparison with a single-stack converter under identical input conditions.

Main Results:

• The implemented 4-stack RF-DC converter achieved a high conversion efficiency of 73.1%.
• A high DC output voltage of 34.2 V was obtained with an input power of 21 dBm per stack and a 4 kΩ load resistance.
• The proposed RFIN effectively combined the DC output of individual stacks while maintaining common-ground integrity.
• The compact size of the 4-stack converter was 24 mm × 123 mm.

Conclusions:

• The proposed common-ground, multiple-stack structure with the novel RFIN is effective for high-efficiency, high-output voltage RF-DC conversion.
• This design offers a viable solution for advanced energy harvesting and wireless power transfer applications.
• The single-layer PCB implementation demonstrates the practical scalability and integration potential of the proposed architecture.