K. Pirapaharan, H. Kunsei, K. Senthilkumar, P. R. P. Hoole, and S. R. H. Hoole, “A Robust, 3-Element Triangular, Reflector-less, Single Beam Adaptive Array Antenna for Cognitive Radio Network: Inter-element Distance Dependent Beam”, JTEC, vol. 8, no. 12, pp. 79–82, Dec. 2016.