Photo patterned thick-film resonators

Microwave circuit demands for high resolution patterning, rectangular cross-sections, sharp edges and smooth surfaces are met by the photo-imageable thick-film technology, successfully competing with traditional screen printing. This paper presents parameters of photosensitive pastes, describes the exposure and development units necessary for carrying out the photoimaging process, depicts manufacturing steps that lead to forming microwave structures with parameters comparable to thin film ones. Edge-coupled filters of centre frequency 6, 12 and 14 GHz, built with microstrip resonators, are the test samples. The transmission and reflection characteristics of filters are measured using a vector network analyser and compared to the simulated characteristics.