Tunable antenna could end dropped cell phone calls

Why do cell phones drop calls? Like a radio dial tuned to different frequencies (stations), cell phone antennas have tuning circuits that quickly switch frequencies when controlled by a voltage applied to a tunable capacitor. Cell phone companies want to improve these circuits to pack more discrete signals into a finite allocation of spectrum and minimize those pesky dropped calls. A five-year, multidisciplinary collaborative research effort based at Cornell has resulted in the world's best material for tunable capacitors - broadly called a tunable dielectric, a special insulator whose ability to store electrical charge changes when a voltage is applied. The research was published online Oct. 16 . "This is a radically different material compared to what people have been using for decades," said Darrell Schlom, the Herbert Fisk Johnson Professor of Industrial Chemistry at Cornell, who led the international team. "What we have discovered is the world's lowest-loss tunable dielectric." ("Loss" refers to wasted energy, which drains cell phone batteries.