Abstract:

Space-Based Solar Power (SBSP) presents a promising solution for achieving carbon neutrality and Renewable Electricity 100%(RE100) goals by offering a stable and continuous energy supply.However,its commercialization faces significant obstacles due to the technical challenges of long-distance microwave Wireless Power Transmission(WPT) from geostationary orbit.Even ground-based kilometer-scale WPT experiments remain difficult because of limited testing infrastructure,high costs,and strict electromagnetic wave regulations.Since the 1975 NASA-Raytheon experiment,which successfully recovered 30kW of power over 1.55km,there has been little progress in extending the transmission distance or increasing the retrieved power.This study proposes a cost-effective methodology for conducting long-range WPT experiments in constrained environments by utilizing existing infrastructure. A deep space antenna operating at 2.08GHz with an output power of 2.3kW and a gain of 55.3dBi was used as the transmitter.Two test configurations were implemented:a 1.81km ground-to-air test using an aerostat to elevate the receiver and a 1.82km ground-to-ground test using a ladder truck positioned on a plateau.The rectenna consists of a lightweight 3×3 patch antenna array(0.9m×0.9m),accompanied by a steering device and LED indicators to verify power reception.The aerostat-based test achieved a power density of 154.6mW/m ,which corresponds to approximately 6.2% of the theoretical maximum.The performance gap is primarily attributed to near-field interference,detuning of the patch antenna,rectifier mismatch,and alignment issues.These limitations are expected to be mitigated through improved patch antenna fabrication,a transition from GaN to GaAs rectifiers optimized for lower input power,and the implementation of an automated alignment system. With these enhancements,the recovered power is expected to improve by approximately four to five times.The results demonstrate a practical and scalable framework for long-range WPT experiments under constrained conditions and provide key insights for advancing SBSP technology.

Key words:

wireless power transmission, space-based solar power, deep space antenna, DSP, KDSA, KARI, rectenna, aerostat