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: May 20, 2024. [Online]. Available: https://penerbit.uthm.edu.my/ojs/index.php/ijie/article/view/12883