Influence of the fabrication errors on multilayer thick film circuits

The effects of fabrication errors in multilayer millimetre-wave components have been investigated, both through simulations and measurements on practical circuits. This paper provides useful guidelines to the circuit designers on the magnitude of fabrication errors that are acceptable, and presents data not previously reported in the literature. A particularly significant error that was quantified was that of skew between conductors on different layers, where it was found that a skew angle of only 0.1deg resulted in very significant changes in bandwidth and insertion loss. The work was supported by a detailed investigation on a 35GHz, multilayer edge-coupled band-pass filter, which was fabricated on alumina substrates using photoimageable thick film process.