Transmission Gain While Retaining Negative Refraction Property

"Our simulation and experimental results show that the addition of the battery powered semiconductor diodes not only provided gain, but also maintained the negative index of this kind of metamaterial," said Doctor Hao Xin of the Department of Electrical and Computer Engineering at the University of Arizona. "It is demonstrated, to our knowledge for the first time, that negative index can be obtained with net gain."

Xin says this type of active metamaterial will be very useful not only in designing and achieving new and high performance microwave circuits and antennas, but can also shed light on metamaterial applications at other spectra including optical frequencies.

Metamaterials are engineered composite materials designed to provide unique properties that do not exist naturally in materials, such as negative index of refraction, or the ability to bend and redirect light rather than reflect it. Studies of the engineering and processes of these materials may lead to many new phenomena and exciting applications, including advancing the development of near unlimited or "perfect" lenses and new improved types of microwave antennas and circuits for next level wireless communication and sensing.

Dissipated loss has been a major limitation to these applications becoming reality. Xin notes that the results of this research demonstrate that loss in metamaterial can be compensated, an important step towards practical experimental metamaterial with gain in the microwave domain. These data may also shed light on optical gain systems, Xin said.; Source: University of Arizona College of Engineering