Three-Port Devices: Lossless, Matched, and Reciprocal

This lecture covers the fundamental properties of three-port devices, explaining why a three-port cannot be lossless, matched, and reciprocal simultaneously. It delves into the conditions for lossless, matched, and reciprocal three-port circuits, as well as the implications of nearly matched ports. The lecture also explores the concept of circulators and Y-junctions, discussing the design and characteristics of these components. Additionally, it examines the behavior of lossy three-port circuits, such as resistive dividers and Wilkinson dividers, highlighting the matching conditions and network equivalences. The lecture concludes with a study of symmetric and asymmetric excitations in three-port devices, analyzing the reflection coefficients and impedance matching at different ports.