IEEE Antennas and Wireless Propagation Letters, vol. 10, page. 738 - 741, 2011-07
IEEE Transactions on Antennas and Propagation, vol. 61, no. 4, page. 1573 - 1580, 2013-04
IEEE Transactions on Antennas and Propagation, vol. 60, no. 12, page. 5932 - 5938, 2012-12