coaxial_to_coplanar__qfn_to_coplanar

Hallo,

within our module, there are quite long cascades of packaged subdevices and coaxial connectors.

f=5GHz
coaxial-SMA/K - QFN package1 - QFN package 2 - etc. - coaxial-K

f=20GHz
coaxial-SMA/K - QFN package1 - QFN package 2 - etc. - coaxial-K

Is there any rule of thumb how tight i can place these subdevices.
lambda/10 coplanar lines between two devices would be possible. For the lower frequency pathes I would prefer to use lambda/50.

Thanks.
elektr0

Hallo,

really, nobody has a suggestion.
To make it more simple, let us just think of a mixer (RF/LO=16-32GHz) in a plastic surface mount housing (QFN). How tight can we place the coaxial connector.
Evaluation Board designs from the supplier show 10mm distance between 2.92mm coaxial connector and the mixer.

What do you think ?

Thank you for your help.

elektr0