Printed Electronics Fabrication of Laminated Conductors for Loss Reduction in RF Circuits

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Printed electronics (PE) differs from conventional subtractive (eg. etching) fabrication methods and is insteadone of a number of methods to fabricate circuits/devices by additively depositing conducting or dielectric(insulating) material. These include traditional printing methods like flexography, and more recently developedtechniques like aerosol-jet printing. PE methods offer lower fabrication costs and are suited to flexiblesubstrates. They have not yet found widespread use at high wireless communications (RF) frequencies. Thereason is this : RF circuits are usually comprised of conducting metallic patterns printed on dielectricsubstrates. Subtractive fabrication methods are suited to produce conducting tracks as single thick (relativelyspeaking) conducting layers. But no matter how thick the conductor is, the so-called electromagnetic skin effectresults in the current flowing within a thin layer of the conductor. Thus the effective resistance (and henceunwanted power losses) is larger than it could be if the current could be made to spread over a larger crosssection of the conducting track. How this can be achieved was in fact shown in 1951, namely that instead of asingle conducting layer one should use laminated conductors comprised of very thin conducting layersseparated by extremely thin dielectric material, of just the correct thicknesses. Electromagnetic fieldpenetration of this laminated conductor can then be many skin depths thick and the currents will as a resultflow over larger portions of the available conductor cross-sections. This results in greatly decreased powerlosses. But subtractive fabrication methods are not suited to making laminated conductor circuits. This researchwill use computational electromagnetics analysis to design laminated conductor circuits, and PE flexography tofabricate them in an effort to start making PE fabrication methods available for RF circuits. One possibleapplication is by a Canadian company developing one of the world's first fully integrated advanced headprotection solutions for security and military personnel.