Large deployable reflectors usually are composed of (metallic) meshes as reflecting surfaces being tensioned via a stiffening structure. In order to overcome the inherent deviation of their shape from the ideal one, a new type of reflecting surface is investigated together with a stiffening structure composed by tensioned membranes. It is made of carbon fibre reinforced silicone generating a double curved non-tensioned shell-membrane. Relevant RF and thermo-mechanical characteristics are presented. The overall reflector concept is also discussed together with first results obtained from scaled laboratory models.