can a bare ended coax cable be called an applicator?
can a bare ended coax cable be called an applicator?
(OP)
If you take a short length of coax cable on a waveguide to coax adapter (large size coax, tbd), fed by a 1.2 kW 2.45 GHz magnetron and isolator, and trim the end to expose the correct length of center conductor, and then inserted that end into a volume of dielectric material; would the wave propegate roughly as a spherical front to uniformly heat the block of material?
Example would be killing termites in a tree by drilling to the core and zapping. Actually, I need to deliver microwave heat to the interior of a block of material inside a vacuum chamber. It would be easier for me to use coax than a circular waveguide due to less complex feedthoughs and drilling a smaller hole. Uniformity is not a serious issue either.
Example would be killing termites in a tree by drilling to the core and zapping. Actually, I need to deliver microwave heat to the interior of a block of material inside a vacuum chamber. It would be easier for me to use coax than a circular waveguide due to less complex feedthoughs and drilling a smaller hole. Uniformity is not a serious issue either.





RE: can a bare ended coax cable be called an applicator?
RE: can a bare ended coax cable be called an applicator?
Since there is not adequate ground plane, the shield on the coax will have significant current flowing on the outside of it. It might leak out of the tree, or whatever, and cause some health risk as the long coax line's outer shield becomes a second antenna.
In order to pass a coax through to a vacuum chamber, you will either need a big vacuum pump that can pump down despite the atmosphere leakage, or you will need to use a glass to metal seal in the wall of the coax chamber.
Probably the biggest thing that you will have trouble with is the Efield arcing over. There is an effect called multipactor that you should study, where at an atmosphere equivalent to around 90,000 feet altitude, the rarified air will cause a cascade effect where the signal arcs over between the center conductor and the ground shield. If it does not actually arc over, it will at least glow a funny purple color! You might have to seal the end of the coax line with something that has a very high dielectric breakdown strength to get away with it. I think Dow Corning makes some dielectric pasts that you could load the hole in your plastic block with so there is no rarified air in the hole.
RE: can a bare ended coax cable be called an applicator?
can I expect useful heating energy to radiate from the coax outer conductor in vicinity of radiating terminus? in other words, can I take advantage of the 'loss' to heat with? would a ball on core end help?
RE: can a bare ended coax cable be called an applicator?