Sinusoidal Waves in a Lossy Medium

Lossy Medium

A medium in which a traveling wave’s amplitude decreases as the wave travels.

Attenuation Factor

The factor e^(-αx) that causes wave amplitude to decrease with distance

Attenuation Constant

• α

• The constant that determines how rapidly a wave decays in a lossy medium.

Neper per meter (Np/m)

Unit of Attenuation Constant

dimensionless

Actual Dimension of is 1/m; “Np” is ____________

y(x, t) = A(e^(-αx))cos(ωt - βx + Φ_0)

Lossy Wave Form

A(e^(-αx))

Wave Amplitude in a Lossy Medium

Wave Envelope in a Lossy Medium

The envelope is bounded by +A(e^(-αx)) and -A(e^(-αx))

constant

Wave Envelope in a Lossless; The envelope remains _______ with distance

decreases exponentially

Wave Envelope in a Lossy Medium; The envelope _______________________ with distance

amplitude decay

A larger α means faster _______________

phase constant

Meaning of β is that it is the ______________ usually measured in rad/m