mounting rf diodes in cavities etc?

[coppercone2]

If you have those really low capacitance diodes (old) how do you go about mounting it in a cavity?


Are these parts designed to be soldered in place with a oven with pastes and preforms, or do they require conductive epoxy? Or is it meant for spring contacts? perhaps a spring copper baffle that deforms with a screw?

Like those high GHz diodes you can buy, look like MELF packages. Its tiny. its fast. Its possibly soviet and has no name or documentation.

[CaptDon]

My only experience is with the old 1N23E / 1N23ER and the similar 1N21 S band and X band mixers which use a mount with a form of spring finger contacts. Some of the diodes have a removable cap that fits over the nubs so you can reverse a 1N23 to replace a 1N23R. I have also used the little tiny X band Gunn diodes that look like a saccarin tablet. they fit into a sort of machined pit in the waveguide with a quarter wave resonator post that screws down against the diode to make D.C. and R.F. connection. I suspect you may be looking at something similar to the X and Ku Gunnplexer styles of mounting. Don't know if that helps?

[coppercone2]

hmm I think these are like 100GHz + though. I forgot but it was very high for spring fingers I think



I thought of this.

1) big shallow counterbore
2) less shallow less wide counterbore
3) threaded hole

1) solder thin plate across big shallow counterbore, make flush
2) insert screw into threaded hole. The screw should be able to deform the thin plate slightly so it squeezes the diode in place

like a burst disk almost. then its all smooth

so it works like arteries

[joeqsmith]

Shown is an old mount built into a horn.   Maybe try Google images. 

https://www.eevblog.com/forum/rf-microwave/how-to-mount-microwave-slug-diodes/

[mr ed]

You can solder a modern SMD diode  on to the end of some hard coax and place it in the cavity. Something like a BAT24 which are current parts and under 2 bucks. Some are good to over 60GHz.