N. . Md Jizat, Y. . Yamada, and Z. . Yusoff, “Multibeam Array Antenna with Compact Size Butler Matrix for Millimeter-Wave Application”, IJIE, vol. 15, no. 3, pp. 140–152, Aug. 2023, Accessed: Aug. 07, 2026. [Online]. Available: https://journal.uthm.edu.my/index.php/ijie/article/view/12883