Ma, Li, Lei Wang, and Xiaodong Chen. “Design of 4×4 Multi-Layer Butler-Like Matrix With Flexible Phase Differences and Filtering Integration for 5G Applications”. Applied Computational Electromagnetics Society Journal (ACES) 40, no. 02 (February 28, 2025): 130–137. Accessed June 2, 2026. https://journals.riverpublishers.com/index.php/ACES/article/view/24787.