Phase Factor in wave propagation (lossy medium): does the distance matters?

In summary, the phase factor in electromagnetism theory, usually denoted as BETA, is a constant that represents the amount of phase shift that occurs as a wave travels one meter in a lossy medium. Unlike the attenuation factor (ALFA), there are no examples that directly relate the phase factor to distance. However, the phase factor does play a role in the total attenuation of a plane wave propagating in a lossy medium, along with the frequency, distance, and ALFA. The phase factor has units of rad/m and is multiplied by the distance to give the phase shift in radians. The attenuation in dB can be calculated using the formula 8.686·ALFA·d.
  • #1
Ionito
14
0
In the electromagnetism theory, the phase factor or constant (usually BETA) in wave propagation for lossy medium has the unit rad/m.

I understood that it must be interpreted as the amount of phase shift that occurs as the wave travels one meter.

However, differently of the attenuation factor (usually ALFA), I cannot see examples relating the phase factor to the distance. In other words, we can see the signal attenuation as the form of 8.69*ALFA*d, where d is the distance between the sender and the receiver. However, this distance "d" is not used in conjunction with the phase factor BETA. Is it right?

Can anyone provide me a complete example of the total attenuation (in dBs), given ALFA, BETA, frequency, and distance d, for a plane wave propagating in a lossy medium?

Thanks
 
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  • #2
Yes, the phase factor appears in the wave equation as beta(phase shift) multiplied with the distance in the direction of wave propagation.i.e if wave is traveling along z direction then phase factor = beta(z)
along with the time dependence wt.

beta is radians per meter,this multiplied with distance gives the phase shift in radians.
 
  • #3
See the Definitions section of

http://en.wikipedia.org/wiki/Phase_constant#Phase_constant

The propagator in transmission lines is complex; γ = α +iβ. Alpha (α) has dimensions of nepers per meter. Beta (β) has dimensions of radians per meter. The attenuation in dB is 8.686·α·d.

Bob S
 

1. What is the phase factor in wave propagation?

The phase factor in wave propagation refers to the change in phase of a wave as it travels through a medium. It is affected by the properties of the medium, such as its conductivity and permittivity, and can impact the intensity and direction of the wave.

2. How does a lossy medium affect the phase factor?

A lossy medium, which has a non-zero conductivity, can cause the phase factor to decrease as the wave travels through it. This is due to the absorption of energy by the medium, resulting in a loss of amplitude and a change in the phase of the wave.

3. Does the distance traveled through a lossy medium impact the phase factor?

Yes, the distance traveled through a lossy medium can impact the phase factor. As the wave travels further through the medium, the phase factor will decrease, resulting in a change in the wave's direction and intensity.

4. How does the phase factor relate to signal attenuation?

The phase factor is directly related to signal attenuation in a lossy medium. As the phase factor decreases, the signal will experience more attenuation, or decrease in amplitude, due to the absorption of energy by the medium. This can result in a weaker or distorted signal.

5. Can the phase factor be manipulated in a lossy medium?

Yes, the phase factor can be manipulated in a lossy medium through the use of materials with different conductivity and permittivity properties. By altering the properties of the medium, the phase factor can be controlled to some extent, allowing for manipulation of the wave's direction and intensity.

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