MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, vol. 50, no. 3, page. 701 - 705, 2008-03
IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS, vol. 18, no. 1, page. 55 - 57, 2008-01
ETRI JOURNAL, vol. 26, no. 6, page. 669 - 672, 2004-12