Design Methodology and Technological Flow of Screen-Printed Thick-Film Sensors

In this paper, the design considerations and basic equations related to thick-film screen-printed sensing devices are included. The geometry of the device and the patterns of the functional sensing film, or of the electrodes are taken into account for the determination of the operational frequency, noise voltage, quality factor and other key parameters, related to the proper work of the resistive, capacitive and surface acoustic wave based sensors. The determination of some parasitic components and possible errors is also provided. The focus is put on the most widely spread coating patterns related to this technology – meander and comb-shaped. The technology flow chart of the screen-printing technology is given and the approaches for fine-tuning the resistance at the thick-film resistive sensors are discussed. Comparison of the typically used materials for substrates, resistive, conductive, and dielectric coatings is made. Criteria for the selection of the different pastes or inks for specific applications are mentioned.