Abstract: Space-to-ground microwave wireless power transmission is a critical enabling technology for space solar power satellites (SSPS). The microwave power transmitting array on the satellite converts DC power to microwave power, transmits the power toward the ground, and steers the beam with high precision. As critical onboard payloads for SSPS, these arrays demand strict lightweight design and high integration. A lightweight prototype using electromechanical-thermal co-optimization was designed and fabricated. The antenna structure, thermal control subsystem, integrated circuits, and cabling, were co-designed integrated into one unified structural system. This system delivers structural support, thermal management, electromagnetic radiation, and power distribution. A prototype with dimensions of 1m × 1m was developed and comprehensive experimental validation was conducted. Measured results show 19.9kg/m² areal density, 874.9W/m² power density, and 0.102° precise beam pointing accuracy. These results demonstrate that the co-optimization approach significantly improves array integration and reduces areal density while maintaining reliable and stable beam performance. The prototype advances the technology readiness level of microwave power transmitting arrays and provides solid and practical technical support for real future in-orbit demonstrations and SSPS construction.

Key words: space solar power satellite（SSPS）, microwave power transmission, transmitting array, highly integration, integrated design