Japanese researchers are using microwaves to power drones, and this project may pave the way for a new type of drones. rocket…
Currently, most rockets generate thrust using controlled explosions of solid or liquid propellants, which can account for 90% of their total weight. However, a new study published in Spacecraft and Rockets Journal demonstrates the potential of using an alternative fuel source: microwaves.
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Microwaves are a type of electromagnetic radiation. Thus, they are packed with energy that can be converted to electricity, just as sunlight can be converted to energy using solar panels. In a new study, researchers generated electricity to power free-flying drones by emitting microwaves directly at them.
“In unmanned aerial vehicle experiments, microwave energy is transmitted from an antenna on the ground to an antenna on an unmanned aerial vehicle. A rectifier is used to convert RF radiation. [radio frequency] to DC [direct current]and DC power is used to drive the drone motors. We call it ‘rectenna’ (rectifier + antenna), ”one of the authors of the new study, Kohei Shimamura of the University of Tsukuba, told Space.com in an email.
Previous studies of microwave energy movement have used low frequency waves, but it has been found that as the frequency is increased, the energy transfer efficiency also increases. Taking this into account, the research team used high frequencies (28 gigahertz) to lift a 0.4 kg drone off the ground.
Positioned directly over the microwave beam source, the transmitted power allowed the drone to reach an altitude of about 2.6 feet (0.8 meters) in 30 seconds. “We used a sophisticated beam tracking system to ensure that the drone received as much microwave power as possible,” Shimamura said in a statement. statement…
During the experiment, 30% of the emitted microwaves were captured by the drone, and 40% of these microwaves were converted into electricity to provide propulsion.
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“These results indicate that more work is needed to improve transmission efficiency and to carefully assess the feasibility of this approach to propulsion for aircraft, spacecraft and rockets,” Shimamura said. “Further research should also focus on improving the beam tracking system and increasing the transmission range power beyond what has been demonstrated in our experiment.”
While new research demonstrates the potential of a microwave-powered propulsion system, the technology remains largely in its infancy, especially given its potential use for rocket flight.
“The big challenge is to trace the microwave oven to the rocket until it reaches an altitude of 100 km. [approximately 62 miles]… To do this, it is necessary to accurately control the phase of the thruster and microwaves. In addition, phase matching of multiple high power microwave sources is a challenge for the future, Shimamura told Space.com in an email. – Cost is a major issue as well as a technical issue. Construction of a powerful source of several MW. [megawatts] is equivalent to building a fusion power plant, and the cost of launching a rocket is currently very high. ”
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