Fabrication of low cost microwave circuits and structures using an advanced thick film technology

The explosive growth in applications for microwave circuits and systems is demanding new approaches to circuit technology to satisfy system demands. With applications such as phased array antennas, satellite communications and car collision avoidance radar, there is a high volume demand for microwave circuits. Established circuit technologies, primarily thin film, are too high in cost to meet these demands. What is needed is a lower cost technology which still offers high performance. Such a technology is described here. Advanced thick film materials are combined with photoprocessing techniques to provide outstanding circuit performance. Line resolutions of 12 μm are available, together with via dimensions of 50 μm. The electrical performance of the materials is also excellent, with very high conductivity lines and low loss, low dielectric constant dielectric materials. The paper briefly reviews this technology. The majority of the paper concentrates on describing examples of microwave components and their performance when fabricated using this technology. It is shown that it is possible to equal or even exceed thin film performance at frequencies up to at least 80 GHz using the conductor material on ceramic substrates. Particular attention is paid to novel microwave structures using this technology. A structure referred to as “microstrip on dielectric” is illustrated and performance figures are given. Due to the compact form of this structure, small size circuits with low material costs and hence low overall cost result. Test results on components fabricated using this approach are also given