foam substrate

it is attractive to use foam as a substrate
for mpa and their feeding networks when considering cost and low loss
however a downfall is the size of the radiating element and qwt's

i have an application where the foam is desired for COST purposes
however i need a dielectric constant on the order of teflon-glass
approx. 2.2 - 2.5 due to size constraints

is anyone aware of such a foam?
or something quite similar

remember COST is the driving factor

thanx

gb :sm21:

I think you are not going to find any. Foam of any type is what it is because of the large proportion of gas. This cuts down the overall average dielectric constant.

i should reiterate and note that whether the material is foam or not is not as relevant as price and dK

i have found an Arlon product FoamClad which is a copper clad foam with a dK of approx 1.35 at 40 mils (no plated thru holes in processing however)

this material is around 50 US dollars for an order under 1000 square feet in sheet sizes of 24" x 36"

which is magnitudes cheaper than teflon glass
this price difference is what i am looking for however a slightly higher dK
would be more attractive

gb