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Partnership Strengthens Ties between Western PA Materials and Circuit Communities

Article Posted On 3/10/2011

The field of high-frequency circuit design is receiving much attention recently as improved semiconductor devices allow for the potential of a range of high-speed digital and analog systems. With ever increasing demand for more data, the available frequency spectrum becomes more and more crowded. One of the few ways forward is to use what we have more efficiently. In communication, this means the ability to use the frequency that momentarily becomes available, hence the need for tunability.

With the help of PITA funding, Carnegie Mellon University professors James Bain, Paul Salvador, and Marek Skowronski are exploring new ways to tune the frequency of RF circuits and at the same time, are developing an important partnership between the work being done in the materials and in the RF circuit communities. This project is a joint effort between CMU and Nokomis, Inc. which develops and markets RF systems for the defense industry.

"The defense market has shifted dramatically towards those who can exploit the electromagnetic spectrum and Nokomis is positioned favorably on this expanding landscape," explains Nokomis Scientist Patrick Fisher. "One important area within this expanding landscape involves frequency agile and multifunctional electromagnetic elements/systems."

In 2000, the discovery (or rediscovery) of resistive switching based on heterostructures of oxide semiconductors set off a flurry of research activity centered on memory and reconfigurable electronics applications. However, the fundamental properties of switching devices and materials still need to be quantitatively established. In addition to providing such fundamental insights, Bain, Salvador, Skowronski and their partners at Nokomis aim to broaden the functionality of such devices from switching between different resistances to tuning the capacitances. Both properties are controlled by the ability to change the distribution of electrically active donors in the layer of the functional oxide by the application of the electric field.

The effect was demonstrated in a model system of single crystal strontium titanate and is being investigated in technologically relevant structures containing thin films of titanium oxide. The tunable capacitor project funded by PITA complements federally funded work on memristors as reconfigurable switches in frequency agile RF systems within CMU's MISCIC Center (MEMS Instrumented Self-Configuring Integrated Circuits), led by Professor. T.E. (Ed) Schlesinger.

In a more general way, this research partnership is developing strong ties in Western Pennsylvania between the materials and circuit development communities at Carnegie Mellon University and the producers of electromagnetic devices and systems at Nokomis, Inc., ultimately strengthening Pennsylvania's competitiveness in the RF circuits and reconfigurable electronics community.