Characterisation of TFMS lines fabricated using photoimageable thick-film technology

This paper describes the performance of thin-film microstrip (TFMS) transmission lines and passive components fabricated using photoimageable thick-film technology. The fabrication of narrow conductors (down to 15 μm) and small feature size via holes is made possible by adding a photoimaging process into the conventional thick-film screen-printing process. With this, thin-film microstrip (TFMS) structures can be implemented, whereas traditional thick-film technology cannot produce such narrow linewidths. TFMS is extremely attractive for the high levels of circuit integration desired in multichip modules (MCMs). Wideband characterisation of these TFMS lines has been performed over the frequency range 1-110 GHz using the TRL calibration technique. The effects of coupling between line segments and discontinuities at bends in meandered lines have also been studied. Miniaturised hybrid couplers are then demonstrated using the photoimageable technology.