Reflection coefficient and reflected power on a lossy transmission line

It is shown that the magnitude of voltage reflection coefficient |ρ| occurring in transmission line theory can exceed unity even for a passive load, and the necessary and sufficient conditions for such an occurrence are investigated. Expressions for the maximum values of |ρ| obtainable for a line of a given characteristic impedance, and the load impedance necessary to produce this value of |ρ|, are given. It is shown that the separation of the time-averaged power into the sum of the so-called incident and reflected powers has a limited range of validity and that when such a separation is physically meaningful, the fact that the magnitude of the reflected power is less than the incident is quite evident, as is to be expected for a passive load.