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February 2015 • The PCB Design Magazine 47 lightning speed laminates about 0.010 or less. These materials will likely cause too much insertion loss for 10 Gbps digi- tal rates and circuit materials with lower loss are necessary. The low-loss material used for 10 GBps ap- plications usually has a dissipation factor of 0.005 or less. The next generation high-speed digital designs will probably be in the range of 25 to 28 Gbps and then another shift for low- loss material will be necessary and these mate- rials will be considered very low-loss materials with dissipation factor in the range of 0.003 or less. Finally, some early work with 56 Gbps has shown that extremely low-loss or ultra-low loss materials with a dissipation factor of 0.0015 or less are necessary. PCBDESIgn InSERTIOn LOSS: A BIggER COnCERn In HIgH-SPEED DIgITAL? continues John Coonrod is a market de- velopment engineer for rog- ers Corporation, Advanced Circuit Materials Division. To read past columns, or to reach Coonrod, click here. Multitasking circuits capable of reconfiguring themselves in real time and switching functions as the need arises—this is the promising applica- tion stemming from a discovery made at ePFl and published in Nature Nanotechnology. Oth- er potential uses: miniaturising our electronic devices and developing resilient circuits. Adaptable electronics is generating signifi- cant interest in the scientific community be- cause of the many applications. Imagine for a moment that one single microchip was capable of accomplishing the tasks of several different circuits. underlying this promising technology are so-called "ferroelectric" materials in which it is possible to create flexible conductive pathways. These pathways are generated by applying an electric field to the material. More specifically, when the elec - tric current is applied, certain atoms moves either "up" or "down," which is known as po - larisation. In re- cent years, the academic world has observed that conductive pathways several atoms wide—called 'walls' – form between these polarized zones. The only problem is that, until now, it was impossible to control how these pathways form. At ePFl, the researchers demonstrated that it was possible to control the formation of walls on a film of ferroelectric material, and thus to cre - ate pathways where they wanted at given sites. The trick lies in producing a sandwich-like struc- ture with platinum components on the outside and a ferroelectric material on the inside. At this point, the researchers have tested their research on isolated materials. The next step consists in developing a prototype of a recon - figurable circuit. leo McGilly would go even fur- ther. "The fact that we can generate pathways wherever we want could allow us to imitate in the future phenomena that take place inside the brain, with the regular creation of new synaps- es. This could prove useful in reproducing the phenomenon of learning in an artificial brain." Electronic Circuits with Reconfigurable Pathways