NIST Researcher Highlights Challenges of Talking Ceramics
Terrell A. Vanderah
In the last three decades, communications technologieshave been completely transformed by the wirelessrevolution. Devices such as cell phones are now socommon that many consumers are forgoing the hardwiredversions altogether. This remarkable technologicalexplosion could not have taken place withoutseveral key historical events, such as Marconi s firstwireless transmission across the Atlantic Ocean in1901, and the discovery of the transistor almost50 years later.Critical to the proliferation of microwave communicationswas the discovery of a small number of ceramicmaterials with special properties permitting them tobe used as dielectric resonators and filters, therebyenabling them to function as talking ceramics. Although the theoretical possibilities and potentialapplications of dielectric resonators were recognized in1939, it was not until the 1970s that ceramics with therequired dielectric properties were discovered byresearchers at NIST and a private company. Theconstruction of commercially viable cellular basestations resulted directly from that work. In the ensuingtwo decades, wireless applications proliferated whilethe size and weight of user devices plummeted.Today, dielectric ceramics are critical ingredients ofresonators, filters, and other key components supportingthe $40 billion wireless communication industry.The success of this technology has created an unendingdemand for better materials, as described by NIST staffin Talking Ceramics, an invited article published inthe Nov. 8, 2002, issue of Science. New microwaveceramics, the article explains, are needed to accommodatean increasingly crowded communicationsspectrum and improve device and base station capabilities,while limiting or reducing manufacturing costs.This situation presents a considerable challenge tomaterials scientists because designing materials withthe desired properties requires an understanding that isnot yet currently available.NIST is responding to this challenge by its aggressivepursuit of research on the phase equilibria anddielectric properties of these important ceramics. TheScience article describes several recent accomplishmentsby NIST materials scientists and others that arehelping to place the search for new dielectric ceramicson a more solid theoretical foundation. In addition,promising, but still exploratory approaches to designingand fabricating new types of dielectric materialsare noted.
Journal of Research of the National Institute of Standards and Technology