The performance over the frequency range 140GHz–220GHz of thick-film CPW lines fabricated from nano-particle silver

Coplanar waveguide lines fabricated using thick-films of pure silver paste (Ag) and also pastes containing silver nano-particles (nAg) were measured in the high frequency range 110GHz–220GHz. Suitable feed lines and pads were designed and fabricated using photoimageable silver ink, to allow measurements to be performed using a wafer-probing station with 75μm pitch CPW probes. Silver nano-particle materials have a particular benefit in the higher frequency ranges due to the high bulk conductivity, resulting in lower bulk loss. Different lengths of CPW lines were fabricated, to allow subtraction of the mismatches between the feeding pads and the coplanar lines under test. The CPW lines were fabricated on various alumina substrates, with purities of 96%. The pastes were prepared at Warsaw University of Technology (Poland), and tested at the University of Surrey (UK).