Using conformal coat on a microwave board

Any one have a recommendation for a conformal coat to use on a microwave board? There are no printed line filters to worry about, only surface mount chip circuitry, up to 1 GHz. I can handle a little extra insersion loss after coating in this application.

These guys make good absorbers (dielectric or elastomeric).
http://www.lairdtech.com/pages/products/index.asp#