convert launcher to cable-to-waveguide adapater??

[ProfDrK]

I have 2 identical launchers and need 2 identical waveguide to coax adapters (all W340) I need 2 adapters to make dielectric measurements using a network analyser at 2.4 GHz. The retailer claims 10 weeks lead time for the adapters, so I thought I'd make them IF you guys say there wasn't anything wrong with that. [I still don't know the best radiator (dipole) to employ in the adapater.] .... Now you say why 10 weeks? Because these were high power waveguide to coax adapters and I was going to use them for double duty (measuring at low power and heating with high power).
I was going to put an N fitting on an aluminum plate and bolt it where the magnetron goes. Bad idea?

 

[Higgler]

Probably bad idea unless you have a drawing of one of them to copy.

I'd find as many photo's of adapters on the web and duplicate them. Or buy a low power one from Pasternack to see how it's constructed.

High power is a specialized area and if you're trying to just attach one to your rf source probe in a microwave oven, that might not work too well. Likely to get arcing on the top and bottom if you don't use a conductive seal between the oven and your adapter. You need excellent contact around the perimeter of an adapter that you'd connect to your oven source probe.


I suggest some on-site consultant help.

kch

 

[ProfDrK]

Pasternack doesn't have them this big (WR340). Web is woeful poor with pictures. Intent for short term is to make measurements at low power, so arcing issues or mating an oven are not an issue. I plan to have the high power units for high power use. Right now, I need measurements and the coax to waveguide adapter at 2.45 GHz just needs to be a clean source.
I am just trying to take advantage of the geometrical similarities between the adapter and the launcher.

 

[Higgler]

The pasternack PE9824 adapter (5 in stock @$492.15 each) is WG284 (0.284" inside width dimension) and has a low frequency performance spec'd at 2.60 Ghz, this frequency has VSWR spec. of about 1.15, this will easily work fine as an antenna placed near your microwave oven probe. TE10 cutoff for this waveguide size is 2.078 Ghz, your oven frequency is 2.45 Ghz. Hence, you really don't need the next larger size WG340 in a microwave oven, although that larger WG340 may attach to your oven probe aperture better.

I've used the same WG284 adapter many years ago. I coupled about 100 watts from a microwave oven into this adapter by placing the adapter atop a water filled tupperware container and locating it a few inches from the microwave source. Orient the polarizations properly of course. You'll may need a swept right angle adapter to get out of the oven with a cable due to height limitations.

You could purchase this adapter and make your own sheetmetal adapter from it to your microwave oven output. If this microwave oven output isn't exactly 0.340" wide to fit your WG340 waveguide, you'll may need some form of adapter anyhow.

good luck,

kch