1. a Howard University, Electrical Engineering Department , 2300 Sixth Street NW, Washington, DC , 20059 , USA
2. f E-mail:
3. b Microelectronics Research Center, University of Illinois , 208 N. Wright Street, Urbana, Illinois , 61801 , USA
4. c Chemical Engineering Bioengineering and Materials Engineering Department , Arizona State University , Tempe, Arizona , 85284 , USA
5. d Electrical Engineering Department , Virginia Commonwealth University , Richmond, Virginia , 23284 , USA
6. e Army Research Laboratory , 2800 Powder Mili Road, Adelphi, Maryland , 20783 , USA