Directional Couplers Explained (English & Tamil) 🔥 | Working, S-Matrix & Types

📡 Directional Couplers – Microwave Engineering | Dr. S. Janani Welcome to this lecture on Directional Couplers, an important topic in Microwave Engineering for Electronics and Communication Engineering (ECE) students. In this lecture, you will learn the working principles, construction, characteristics, mathematical expressions, and practical applications of directional couplers. 📚 Topics Covered: Definition and working principle of directional couplers Four-port directional coupler and power flow Coupling, directivity, isolation, and insertion loss Types of directional couplers: Branch-Line Coupler Coupled-Line Coupler Rat-Race Coupler Bethe-Hole Coupler Lange Coupler Even-mode and odd-mode analysis Construction and working of coupled-line, branch-line, and rat-race couplers S-matrix derivation of a 90° directional coupler Practical design considerations and measurement Applications in antennas, cellular base stations, and microwave systems 🎯 Useful for: ECE students, engineering examinations, university preparation, and Microwave Engineering revision. 👩‍🏫 Presented by: Dr. S. Janani