Faraday cages don't block DC, so use that to provide power.

Then run a simple optical fiber cable for communication to an antenna that lies outside the cage.

If you are really good you have multiple antennas that are kept off (with the circuit physically disconnected from the antenna). If you get hit with a pulse activate the next antenna.

It's possible to make simple electronics that can survive such a pulse, with auto-reset fusible links, and you use those for activating the antenna.

Or even a small door and "push" the antenna out of the Faraday cage when needed.

> Faraday cages don't block DC, so use that to provide power.

Drones carry their own power source - usually a LiPo battery.

What you're proposing would not work if the phaser could just keep firing (which seems likely). Onboard AI seems the solution (assuming the Faraday cage is effective enough, which remains to be seen).

> Drones carry their own power source - usually a LiPo battery.

You misunderstood me. Use that to provide power to the antenna which is outside the Faraday cage, and the battery is inside.

> What you're proposing would not work if the phaser could just keep firing

The phaser has a range though. So program the drone to fly up and away if it gets hit (no need for AI to do that). Then reactivate communication and stay away from the phaser area.

I think this is an expensive solution, which would increase radar cross signature almost certainly. Also, it would protect against a weapon that isn't fielded while doing nothing for any conventional weapons.

Source: I flew UAVs "drones" for the US Army for 482 combat flight hours in Iraq. Lookup the wikipedia for "Ground Control Station" for an old pic of an 18 year old me @ the UAV training center "black tower" in Ft Huachuca, AZ.

Yeah. The solution is likely more along the lines of making the drones cheap and disposable, and fighting these systems with traditional air defense suppression.

Very much agreed. I see this "phaser" system as a neat tool that could work along side conventional anti-air such as Patriot batteries to make it pretty difficult to gain air superiority.

One thing about the Faraday cage is that is has a maximum frequency - when the wavelength becomes comparable to the cell size in the wire frame. Any higher frequency will just go through.

This is a problem as microwaves are in the centimeter range. The mesh then would have to be dense. That would raise aerodynamic issues.

I'm not saying it's not doable. I'm just raising the obvious concerns about basic challenges from the laws of physics.

Wouldn't a large amount of targeted RF incident upon an ungrounded faraday cage induce a large enough charge accumulation to also pose a threat to the drone (and anything around it)?

It's not ionizing radiation. Even if it did that, with a metallic shield on the outside, any amount of static charge on its surface generates zero field inside - this is a perk of metallic shielding.

Two real issues with massive RF energy density:

1. Penetration depth. Even if you have a continuous metallic bubble with no holes, some RF radiation still leaks inside, depending on material nature, thickness, frequency, etc. The amount is small, but it's not zero.

2. If energy density in the RF beam is huge enough, the shield / cage starts heating up. You could conceivably melt it if you take this game far enough, or poke holes in it.

There is a net zero electric field inside, true, but isn't that because a charge accumulates on the inside surface of the cage that is equal and opposite to that induced on the outside surface?

With regard to #1, I agree, but the degree of RF leakage is not universally small - it depends on the frequencies you encounter and the properties of your cage (material, mesh thickness and "pore" size, etc). As frequency increases (and wavelength decreases), your pore size must decrease to effectively block it, eventually becoming a solid shell (through which propellers will, of course, generate no thrust). I agree with #2.

> There is a net zero electric field inside, true, but isn't that because a charge accumulates on the inside surface of the cage that is equal and opposite to that induced on the outside surface?

No. In a conductor, all free charges migrate to the outside surface.

You could put your propellers outside and away from the cage, with their motors inside the cage. This would also greatly reduce the size and weight of the cage.

That might work. The "cage" would be more like a sleeve in the region of the arm - just creeping out on the arm like a mesh tube (or even continuous foil tube) to protect the wires, electronics, and motors. A small hole would allow the motor hub to stick out of the cage, and the prop would be on top of that, outside the cage.

Heck, all the wires, electronics, and motors could be inside the "arm". Then coat that with some EM shield material (like a metal foil).

I like it.

Of course, from "like it" to "it's actually effective" there's still the nagging little field test to perform. It's the old shell-vs-armor game, since EM radiation has a penetration depth - Faraday cages are not magically 100% effective, make a thin enough one, and a powerful EMP would still do some damage inside. So now you need to carry thicker, heavier EMP armor.

I think they are magically 100% effective. Unless the cage is breached, nothing will get through. However, an EMP pulse could melt holes in the foil.

However it also means the drone has no GPS; no wireless signaling; no sensors outside the foil at all. It becomes a dumbfire dead-reckoning device.

> I think they are magically 100% effective.

No, they are not. Even a continuous, zero-hole metallic bubble will leak some radiation inside, depending on frequency, nature of material, wall thickness, etc.

Start here:

https://en.wikipedia.org/wiki/Penetration_depth

then continue reading about absorbance, skin effect, etc.

I see. Only for zero-resistance metal would skin depth be zero.

At microwave frequencies, skin depth is essentially zero (microns anyway) for most metals. So until the bag is melted, nothing will get through.

You don't need a full cage. As the beam can only originate from the ground you can just shield the vulnerable bottom half. Don't see how this weapon can work against sophisticated adversaries.

Ground based targets is part of the scope for the weapon - just mount it on a plane (maybe a large drone!)

Good luck with getting GPS then.

Place the receptor outside of the cage, put a resistor and a biggish capacitor, a varistor and a fuse on the communication line, and it's good enough for any disposable machine.

With a good enough AI and a detailed aerial map onboard, you may not need it.

Line of sight lasers are one possibility, but those are vulnerable to dazzlers.