Predictions of the power needed in 50 years or so imply commercial power levels usages 3 to 5 times greater than today's. Meanwhile, power generation cost per kWh need be about 10 times less. Further, considering the necessity for clean, non-polluting alternative sources of energy, and a trend to abandon nuclear power generation makes solar power sources, increasingly more attractive. However, earth-based solar cell power generation at the predicted level by 2050 implies an unrealistically large earth surface area (about 1/5 of the entire United States). Thus, alternative means must be employed to harness solar power, and space-based solar arrays offer this possibility. This proposal addresses wireless power transmission (WPT) by means of spatial power-combining oscillator arrays that employ high power widebandgap semiconductor devices.
The PIs will address the theoretical and practical aspects of designing very large, low profile, printed, active and self-oscillating injection locked antenna arrays consisting of thousands of A1GaN/GaN Heterostructure Field Effect Transistors (HFETs) to generate a powerful coherent microwave beam. GaN HFETs and their high-frequency, non-linear and noise characteristics will be optimized for DC to RF conversion in WPTs. The proposed studies address widebandgap solid-state device issues central to transmission by microwaves and their implementation in spatial power combining arrays.
The PIs goal are to design a highly stable, efficient and multimode-free oscillator array that is tolerant to multiple device failures. Low cost and self-assembly are other attributes. Their design approach is to start with a fundamental study and analysis of multiple device injection locked oscillators in close proximity with radiating elements and devise techniques to design, optimize and construct large, stable and efficient injection locked spatially combined oscillator arrays. The innovative approaches proposed under this program will lead in understanding of GaN-based device, oscillator and spatial power combination in conjunction with power generated by solar cells. This will open new possibilities in RF power transmission for satisfying projected needs of 2kW per person in 2050, translating to 20 tera Watts.
