Scientists in China have demonstrated a wireless power transmission system that uses a ground-based microwave emitter to beam energy to an antenna array mounted on the aircraft’s underside. Importantly, they were able to do this while both the drone and charging system were in motion.
In tests, the car-mounted system kept fixed-wing drones in the air for up to 3.1 hours at an altitude of 15 metres (49 feet). The key challenge that the team overcame was maintaining alignment between the emitter and the drone during flight, wrote Song Liwei, the project’s leader.
Many comments are about how impractical/useless is this technology TODAY considering easier alternatives… but I see research exploring recharging electric flight devices in flight, which sounds as cool as powerful to have flight devices with larger services and ranges
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I think the biggest problem is that this way you have a beacon to your flying device and your recharging station, it would not be that difficult to build a bomb/missile that follow the trace to the ground station
I think that the “recharging” will always be a vulnerable stage and that the objective is to do that puntually and not a continuous dependence on power supply, but still seems safer and easier to abort than the one done currently with non electric planes, and for defense patrolling you will have more important infrastructures that would be targeted first, I still see only advantages if mature enough
I think that the “recharging” will always be a vulnerable stage and that the objective is to do that puntually and not a continuous dependence on power supply,
For an electric recharge I think you need a decent size infrastucture that you cannot move that much or easily. I don’t think that you can do with a enourmous power bank mounted on a truck.
but still seems safer and easier to abort than the one done currently with non electric planes,
Except that you can refuel a normal plane with just a couple of trucks and a strip of road long enough (Sweden built the Viggen around this principle and even the US has the highway designed to work as temporary airfield by some old law).
While it is easy to hit an airport, it became a lot harder to take out all the roads (in part because you will later need them)and for defense patrolling you will have more important infrastructures that would be targeted first, I still see only advantages if mature enough
Yes, the charging station. Once I take out it, you electric planes are out of order. No more patrolling.
I asume this technology when mature enough will not be surrounded by a single point failure. Allowing electric recharge of flying devices, that already have some battery autonomy, without having to land and take off, is clearly more efficient and less vulnerable. Plus mobile electric rechargers, battery deposits and infrastructure will have the same weaknesses than fuel ones (except electric ones would may blow up a bit less under fire)
I asume this technology when mature enough will not be surrounded by a single point failure.
Up to a point, probably yes.
Allowing electric recharge of flying devices, that already have some battery autonomy, without having to land and take off, is clearly more efficient and less vulnerable.
Maybe is more efficient, but not less vulnerable. To recharge a flying device this way you basically mark the charging station even if you try to hide it, an attack could be carried against the station. Additionally having the drone or plane flying near it give away your position even if you come up with a mobile charging station (you cannot recharge too much far away, physic still stand). Then there is the problem of how much time you need to recharge it to a decent level, I am afraid that it would be in the hours range, and the necessity to keep the alignement, they had this problem also during the test, I suppose in a combat situation it would be way harder and this specific problem will not go away as the tech mature.
On the other hand, to keep the J37 Viggen example, it can be rearmed and refueled in 10 minutes and just need about 500 meters to take off. In this case if you don’t see where the plane land, you also need the time to find it, it not give away its position during the operation with a microwave beacon.
Plus mobile electric rechargers, battery deposits and infrastructure will have the same weaknesses than fuel ones (except electric ones would may blow up a bit less under fire)
Once a battery is damaged, it make no difference that it blow up or not, it is useless. And generally a battery fire is harder to put out.
But it would be interesting to see how it eveolve and if it became mature enough to be used in a real combat situation.
I have the feeling that current refueling in flight procedures are clearly more vulnerable than this approach that do not require physical coupling, for whatever these are useful (increasing operation autonomy, etc) the same for having to land in air carriers to extend patrolling times, this electric alternative seem safer in both scenarios, and at least with no more weak points than the fuel alternatives.
If is necessary to reload ammo no refueling-in-flight technology applies of course.
And if something blow up the damage radio clearly propagate immediately further than a battery fire, though regaring the situation a persistent fire can become also problematic, but these battery issues are still experiencing improvements, same happened with fuel counterparts (self sealing deposits, etc).
If this technology matures also recharging times will drop, we are seeing huge advances in plugged batteries.
I still see many advantages to the concept.
I have the feeling that current refueling in flight procedures are clearly more vulnerable than this approach that do not require physical coupling, for whatever these are useful (increasing operation autonomy, etc) the same for having to land in air carriers to extend patrolling times, this electric alternative seem safer in both scenarios, and at least with no more weak points than the fuel alternatives.
I think they are equally vulnerable, only in different ways.
And if something blow up the damage radio clearly propagate immediately further than a battery fire, though regaring the situation a persistent fire can become also problematic, but these battery issues are still experiencing improvements, same happened with fuel counterparts (self sealing deposits, etc).
My point earlier: while it is true that fuel explode and the damage propagate faster, it is easier to replace a tank (trucks) than a battery that can be made useless just damaging it, no need to destroy it.
If this technology matures also recharging times will drop, we are seeing huge advances in plugged batteries.
Up to a point yes, but it has physical limits (not unlike fuel refuelling, only diverse)
I still see many advantages to the concept.
It can. It need to be seen if it is scale well enough to be used on more than a test in a real life situation.
I mean this is really cool but at the same time doesnt seem usefull? Apparently the peak of modern combat is chinese drones with small bombs and a plastic fiber-optic cable attached to them lol.
There are a lot of different drones being used. For example you can’t use fiber-optic for drones that target something 100km afar. Either way the problem with this device is probably the same as with other anti-air systems - it costs, takes time to produce and to train the operator much much much more than to make a drone.
totaly agree with your firs two points…
re: training and operators - my take on it is this has all the hallmarks of a swarm setup constantly recharging a portion of it’s numbers… Ukraine has illustrated that AI shit’s coming quickly, even if llm’s and jensen huang are wildly out of touch.
I’ve lost count of technologies during my lifetime that had initial skeptics of ‘seems cool, but who would use this?,’ and then that tech became ubiquitous or essential within a decade.
Room-sized computers that required punch cards also seemed cool but mostly useless once.
I have no knowledge in this and it’s early, but what happens to birds in the medium in between the receiver and emitter?
This can’t be good for them.
Nothing. It’s non-ionizing radiation.
Microwaves ovens work by using extreme amounts of energy concentrated into a very small area.
Microwave beams for energy transmission are different.
We’ve known this since at least 1996 when the first paper talking about it was published.
https://www.sciencedirect.com/science/article/abs/pii/0038092X95000834
The biggest obstacle for it is actually RFI.
Edit to add, and here’s a NASA paper from the 1980s talking about it
I think it’s worth saying that while not ionizing, high power high gain RF can cause damage via burns. Not sure how much power/gain is used in this situation though. Staying away from unfamiliar transmitting antennas is in general a good thing.
Holy shit.
Getting the ability to remote charge things via microwave… that are moving?
That’s been basically sci fi nonsense, at a practical level, for a long time.
Anybody remember the Microwave Power stations in SimCity 2000?
If you could actually get this tech working, it has an incredible number of potential applications.
Uh…they actually got this tech working.
Will the US get this tech working? Can’t get anything working after slashing all research and kicking 10,000 phds out of the country.
Cletus and his Ram 1500 is not going to figure this out.
We’ve known about the possibility of doing this for decades.
The NRL did a practical test of it in 2022 iirc.
Neat but 3 hours of loitering is nothing for a fixed wing drone. We have drones that stay in flight for a month or more.
The difference is likely size and expense.
Now you don’t need a 100 million dollar Boeing 737 sized drone to loiter for 3 hours.
Previously small and cheap drones could loiter for 40 mins on an internal battery. Now they can stay up for 3 hours. That can be useful.
Of course these mobile wireless recharging stations will become military targets for the opposition. So the overall combat math isn’t obvious to me, but it’s not a tech I see as obviously useless.
This could be much more straightforwardly a win for civilian applications.
I have a 6 year old electric car that takes 40ish minutes to charge, now BYD has batteries that will go from 10% to 70% in 5-10 mins.
In a few years time these drones will be getting charged from a microwave stream of power from a solar array floating in the upper atmosphere.
But the Trump Navy will use cannons to fire coal up to drones and Tesla sexbots will shovel the coal.
The decreased chargng time comes with a massive increase in charging power. The equivalent in ths scenario is to massvely increase the microwave power - which would likely cook the drone.
I prefer my drones cooked in an old fashioned oven, microwaves leave the middle too cold and the outside too hot.
Yes but you are charging through a conductive cable. It’s not even remotely the same as charging something with microwaves.
The power delivered decreases exponentially with distance. I’m sure you’ve heard the phrase “inverse square law”.
Because you divide the effect and gain by 4pi(r^2) meaning your output is decreased by 75% every time you double the distance.
You’re going to need ridiculously powerful hardware and an enormous amount of electricity to run it on any meaningful distance.
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A concentrated, collimated beam doesn’t act like a point source. There’s of course some amount of scattering and absorption loss due to atmospheric particles, but other than that a fully collimated wireless energy transmission doesn’t lose intensity over distance. Kind of obvious, really, because “where would the energy go?”.
We already have concentrated microwave beams. And they do suffer immense energy loss on longer distances.
If you want to transfer energy via microwaves, your efficency will reach single digits real fast on any meaningful distance.
You are right that the inverse square law doesn’t realistically apply with concentrated beams. But you still have energy loss. Lots of it.
But don’t take my word for it. https://www.nature.com/articles/s41598-022-25251-w
Quickly glancing through the paper it doesn’t really seem to support your claim. They attribute their major losses to the parabolic reflector (meaning they don’t have very well concentrated microwave beams?), and say that developing higher efficiency focusing components is important work for the future. I’m kind of guessing that’s one thing the Chinese are doing.
Still, I’m sure there are relevant losses even in properly focused microwave beams. How much that is, I have no clue, and didn’t see it addressed in the paper. Might have missed it - it was a very quick glance. :)
I’ll be honest, I didn’t exactly proof read every word either.
I think what they meant with parabolic reflector is the reciever. They mentioned they 3d printed a reciever to achieve recors breaking efficency (short range). It’s not so easy to gather and convert the microwaves into electric energy. And it’s probably not very easy to create a concentrated beam either.
But that was my interpretation. I’m not going to pretend I understand everything about this. I could be wrong.
I think the technology to have satellites charge drones in the sky is at least 50 years away.
Exactly, proof of concept was all the scientists needed to see.
Solar power is still more practical
not nearly enough surface area to power a drone.
Has already been done
https://www.geeky-gadgets.com/solar-powered-drone-design-2025/
That thing is just a dollar panel with the bare minimum amount of motors to hold up the solar panel. That not practical at all for someone that also needs to move quickly and fire munitions
If you think that’s not practical, wait until you see something microwave powered trying to make quick moves. I want to see what you think it will do when it suddenly has to pass through an urban environment with a ton of obstacles. Are you gonna MIMO the damned microwave beam!?!?!? With millisecond trajectory updates!?!?!?
Not mention that a microwave power transmitter in war will die faster than any mobile radar station because it’s so god damned trivial to detect and lock onto, you’re losing that bullshit in seconds of turning it on
The only scenario where this wouldn’t be total bullshit is perimeter monitoring drones flying a fixed path, where you for some reason really don’t want to have to have multiple drones in rotation (which honestly doesn’t make much sense either but at least that’s just 80% BS instead of 100% BS)
That drone has no mass and uses all its energy to hold up the solar array. Good luck in winds.
Considering everybody talking about using these things in war it has the benefit of not being a suicide beacon visible to instruments for many many miles, unlike the microwave transmitters everybody else here want to carry with them
Also see;
https://www.pv-magazine.com/2024/05/09/powering-drones-with-ultra-thin-flexible-perovskite-pv-cells/
If you actually want to extend the lifetime of high performance autonomous drones in the field then it’s more practical to do battery swaps
try that with the drone in the article. ain’t gonna work buddy.
You can have solar panels and batteries on the ground, and use them to charge the microwave emitter, which can then charge the aircraft, which now does not need to carry solar panels and as much batteries, and thus has increased payload / range.
This would require two football fields of panels.
The microwave receiver will not be small or efficient
Oh, ok.
Even though this entire post is… about how it is small enough to fit on a drone, and efficient enough to power it for 3 hours.
Ok.
Gotcha.
I’m not sure if you’re aware of this, but densely packed explosive bombs and missiles and warheads tend to be pretty heavy.
… the entire problem with purely onboard solar powered vehicles of any kind is that they have to be absurdly lightweight, flimsy.
That isn’t practical.
It might be purely efficient, in a sense, but it isn’t very useful.
Being able to actually move stuff, that is practical.
Most transportation modes involve the ability to haul stuff.
You know, do work, aka the capacity to make stuff move.
You picking a fight that makes no sense to pick.
You can have solar and batteries be more stationary, and use microwaves to power things that are more mobile, this post is literally the proof of that concept… you can charge a battery with a any kind of power source.
Look heres another massive potential application of this, if you science fiction extend the accuracy/capability of this:
Plop a bunch of solar panels/batteries in the L1 point between the Earth and the sun.
Now, via a set of satellites in something like concentric orbits, you can get absurd amounts of power, beam it back along chains of satellites, snd then beam it to recieving stations on Earth. Or the Moon. Or orbital infrastructure.
Microwave transmission power loss will be waaaay less in space, because there’s no atmosphere.
Same with solar panel efficiency!
Solar Power + Microwave Transmission = Very Good, Actually.
The only two metrics that matter here are W/m^2 and weight.
You can’t make a reasonable microwave receiver lighter than solar film and efficiency peaks around 50% in FIXED installations and you can easily assume less than a quarter (under 10%) when the target isn’t just moving, but is also changing angles and distance (you’d have to put the receiver on a gimbal like for cameras) and now it’s also interfering with flight (propeller airflow, unless you do weird propeller geometries or tilted body flight
Tldr DUMB
Microwave power transfer only make sense between distant fixed line of sight locations with minimal infrastructure available. On earth that’s literally just island mountain tops. Even then it’s easier and cheaper to still just install solar
On the moon, it would basically just mean you have one big generator and everything gets powered by the sun when in sunlight and switch to microwave from the generator when in shadow, which is pretty much the only configuration that even make sense
You can’t make a reasonable microwave receiver lighter than solar film and efficiency peaks around 50% in FIXED installations
https://www.sciencedirect.com/topics/engineering/microwave-power-transmission
In JPL 30 kW power was transmitted for 1.54 km with reception conversion array having an efficiency of 80%
That was 8 years ago.
What I’m describing are… currently extremely active areas of research.
Microwave power transfer has been used for many applications since its inception by Maxwell. Wireless charging of EVs and UAV using microwave power are some of the widely researched examples.
you can easily assume less than a quarter (under 10%) when the target isn’t just moving, but is also changing angles and distance (you’d have to put the receiver on a gimbal like for cameras)
You should maybe look into the level of precision that things like Phalanx CIWS systems have at tracking a moving target, with the ability to throw bullets at it, and hit it.
Or basically any SPAAG type platform that throws rounds down range.
Or I dunno, MASERs used in deep space transmission.
Or all the research that has gone into developing tracking gimbal systems that do intentionally use lasers or some kind of DEW to shoot down small drones, or damage aircraft in flight, or burn out incoming missiles.
Hell of a lot easier to track a friendly aircraft.
and now it’s also interfering with flight (propeller airflow, unless you do weird propeller geometries or tilted body flight
Genuinely no clue what you are talking about.
Are you assuming only like, quadcopters here?
We’ve had RQ 4 drone aircraft the size of WW2 medium bomber planes, with jet engines, for 20 years now.
I’m fairly sure that a jet engine produces a considerable amount of consistent heat.
Do… you think aircraft engineers… do not know… how to handle… heat?
Shall I describe a ramjet to you?
Or maybe we could go with something like the Space Shuttle’s reentry tiles?
In conclusion, you are vastly uniformed as to the state of… not even state of the art technology, that would be incredibly relevant to this discussion.
Those efficiencies are for large senders and receivers. When you have to make it small for a drone the numbers gets worse.
None of those make continous evasive maneuvers. All the things you mention works because the flight path is fully known in advance and you have full synchronization and ability to lock orientation. None of this works on a drone in urban environments where you’ll constantly lose line of sight.
Dude I’m not talking about heat I’m talking about literal about the literal MW receiver’s physical LOCATION on the drone body AND THE ACTUAL PROPULSION IN FORM OF MOVING AIR, because the receiver has to be large, and oriented to the sender at all times, which means there are orientations in which it will block at least some propellers from pushing air physically downwards, unless those also are built to extend far out AND CAN TWIST THEIR ORIENTATION TOO
(remember that propeller flight obeys the laws of Newton, pushing air down keeps you up and if you tilt your drone to align with the microwave center then you must tilt your propellers or you’ll be flying sideways, unless you put receiver on a gimbal in which case it’s stupidly complex and you now have to adjust airflow across non-blocked propellers when the receiver is below some of them)
You can not win an argument by misunderstanding the counterarguments. You lose by not even being able to imagine how a drone actually flies physically in the air, not to mention your lack of ability to just read
Not to mention that you didn’t even ask yourself what happens to a microwaved power transmitter in war. Guess what? It gets targeted and destroyed in seconds. You’re dead now. Bye.
And you can’t even make a drone swarm work. Either you have a dozen transmitters (lol good luck) or a phased antenna array in which lol fucking lmao that thing will spew out heat losses and get banned from operating near any remotely populated area due to radio interference
Getting some Ace Combat vibes
1/r2
Sounds:
- Pretty advanced
- Pretty expensive
- Quite useless (I mean it definitely has its uses, but I think you could find much cheaper and simpler solutions)
“… you could find much cheaper and simpler solutions…”
Heat feelt thanks for your bold show of confidence in my technical capacities. Yet I have to disclose that I’m not exactly sure to be able to compete with a first world power like China.
No, not you! I meant that guy!
Wow that looks a lot like the UKs Taranis bomber drone.
Swapping out batteries in flight would probably be more efficient.
We don’t even have automated battery replacement working on the ground, while stationary.
Building aircraft with a whole bunch of their body and mass that significantly changes, in flight, is extremely expensive and difficult.
Its why the V22 Osprey is widely regarded as a death trap, why we stopped building swing wing F-14s.
… Have you ever tried to uh, remove your car’s rear seats, while on the highway, at 60 mph, and then also installed new seats, from a neaby car travelling alongside you?
Ok now do that with aircraft, at 15k feet, going 600 mph.
Yeah I’m sure that’ll be about as efficient as Elon Musk’s approach to designing the Starship+HeavyBooster.
Yeah I’m sure that’ll be about as efficient as Elon Musk’s approach to designing the Starship+HeavyBooster.
Compared to microwave energy transmission which has even worse efficiency.
Ok now do that with aircraft, at 15k feet, going 600 mph.
This is about drones. At 5 km distance and close to mach 1 you can absolutely forget any microwave based charging systems.
You are aware that we’ve been shooting drones out the sky with lasers for about a decade now, right?
Not too long ago DHS/CBP freaked out over some balloons in Texas, thought they were cartel drones, shut down the airspace, burned them outta the sky with truck mounted lasers.
JPL got 80% microwave power transmission efficiency at ~1.5 km, 8 years ago.
Granted, that was a fixed land point to fixed land point test, but also, it was 8 years ago.
I’ll take 50% efficiency loss over 10% chance of ‘everything explodes and crashes’ any day.
Sounds cool. And also like an attack vector.
