If you folded it down (disconntected the rods, from the unit and coils, so it fits into a carry-on), then I don't know why they'd have any problem with it. I mean, no-more-so than any other type of electronic device which is frequently and always carried as "carry on". You know, like people who bring a lap-top computer, for instance, is another type electronic device. Why would the airline have some special policies for a metal detector, verses some other type appliance? Provided it's not explosive, or could be used as a weapon that is, then I don't know why a detector would be singled out, over another device, provided it's broken down into your allowed size-carry-on. When they scan, I suppose the metal pole-rod would be a "shape" that they'd see in their inspection/x-ray, eh? But no-more-so than a lady's curling iron? etc... which ..... once they see it's not a weapon or banned substance, then .... I don't see why not.
And for sure if you put it as checked luggage, then for sure there would be no problems. It would be no different than any other checked baggage that is routinely done: musical sound equipment, medical devices, and so forth can all have electronics of various shapes and sizes.
