A Planar Rectenna at 2.45 GHz With Circular Polarization for Wireless Power Transmission

This study presents the design and analysis of a compact circularly polarized rectenna operating at 2.45 GHz, intended for wireless power transmission (WPT) applications. The proposed structure includes a 2x2 patch array antenna and a voltage doubler rectifier circuit, both optimized to maximize RF-DC conversion efficiency. Simulations, carried out using ADS and another electromagnetic solver show excellent performance with a reflection coefficient (S₁₁) below -10 dB, an axial ratio below 3 dB in the ISM band, and a maximum gain of 11.14 dB for the antenna array. The RT5880 substrate (εᵣ = 2.2, tanδ = 0.0009) and 35 μm metal thickness were chosen to balance performance and simplicity of design. The results show an RF-DC conversion efficiency of up to 73.69% at 27 dBm, confirming the potential of this design for mobile WPT applications such as powering drones.