New Low Cost Substrate (Duroid) for Hybrid Microwave Integrated Circuits (MICs) in Wide Band

Because of its lower dielectric constant and loss tangent, and its greater surface smoothness, fused silica is very suitable for use in the KU band and above, but its cost is very high. The purpose of this paper is therefore to select a new substrate which competes with fused silica on the grounds of lower cost; to adapt the hybrid technology to this new substrate; to show ,comparing the measured performances of a filter realised on fused silica and on this new substrate, that the latter is suitable for MICs in the wide band, but not in the narrow band; and to describe an application of this substrate in the 22–24 GHz band. Thus, after an investigation of the electrical parameters and of the costs of different substrates, Duroid was selected and compared with silica. This substrate is composed of a non‐woven glass microfibre reinforced by polytetrafluorethylene; its microwave quality is theoretically almost similar to that of the fused silica one but its cost is much lower. The adaptation of hybrid techno...