Metamaterial Advances for Radar and Communications.

Metamaterial antennas have progressed considerably in the last few years. Kymeta demonstrated transmission to satellites and back using 20 and 30 GHz antennas about the size of a laptop, which use metamaterial resonators for phase shifting. Echoclyne and Xerox PARC have developed metamaterial arrays for radar. The Army Research Laboratory funded the development of a metamaterial 250 to 505 MHz antenna with a λ/20 thickness. Complementing this, a conventional tightly coupled dipole antenna (TCDA) has been developed which provides a 20:1 bandwidth with a λ/40 thickness. Target cloaking has been demonstrated at microwaves using metamaterials. Stealthing, by absorption using a thin flexible and stretchable metamaterial sheet, has been shown to provide 6 dE absorption over an 8 to 10 GHz band, with greater absorption over a narrower range. Metamaterial has been used in cell phones to provide antennas that are 5× smaller (1/10th λ) having 700 MHz to 2.7 GHz bandwidth. It has also provided isolation equivalent to 1 m separation in antennas with 2.5 cm separation and is used for phased array wide angle impedance matching (WAIM). [ABSTRACT FROM AUTHOR]