Experimental study on sensors in a car engine compartment driven by microwave power transfer

In this study, we examined the microwave power transfer to sensors in a car engine compartment. First, we calculated the transmission efficiency in free space. We changed the transmission distance, and confirmed a theoretical limit value of the transmission efficiency in free space. Second, we simulated the transmission efficiency using the engine compartment model. We changed the direction of the antennas, and obtained 2.8% as the highest transmission efficiency in the required antenna position. Third, we conducted a microwave power transfer experiment in the engine compartment. Then, we changed the direction of the antennas and obtained 1.2% as the highest transmission efficiency. Finally, we changed the position of the antennas to improve the transmission efficiency and simulated the transmission efficiency. As a result, we obtained 8.4% as the highest transmission efficiency.