IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, vol. 56, no. 3, page. 626 - 631, 2008-03
SOLID-STATE ELECTRONICS, vol. 49, no. 8, page. 1335 - 1340, 2005-08
IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, vol. 46, no. 11, page. 1604 - 1613, 1998-11