EM wave with circular polarization interferes with conductor

In summary, the conversation discusses the interference of an electromagnetic wave with circular polarization traveling in the z direction with a perfect conducting surface in the xy plane. The first point is to find the reflected wave, which involves applying boundary conditions at z=0 and solving for the parallel electric and magnetic field components. For the second point, the goal is to calculate the induced charge density and surface current on the conducting surface, which may be caused by the wave. However, the method for calculating this is not clear.
  • #1
adremja
1
0

Homework Statement


EM wave with circular polarization travels in directon z interferes with perfect conducting surface xy.

1. find reflected wave
2. calculate induced charge density and surface current induced on conducting surface

Can you verify if I started point 1. correctly, and give some idea how to calculate point 2. Because in Griffiths I can only find info that there are volume currents which in limit of perfect coonductor become true surface current.

2. The attempt at a solution

I started the first point

$$
E_I(z,t) = E_{0I}(\hat{x}+i\hat{y})e^{i(k_1z-\omega t)}
$$
$$
B_I(z,t) = \frac{1}{v_1}E_{0I}(-i\hat{x}+\hat{y})e^{i(k_1z-\omega t)}
$$

$$
E_R(z,t) = E_{0R}(\hat{x}-i\hat{y})e^{i(-k_1z-\omega t)}
$$
$$
B_R(z,t) = -\frac{1}{v_1}E_{0R}(i\hat{x}+\hat{y})e^{i(-k_1z-\omega t)}
$$

$$
E_T(z,t) = E_{0T}(\hat{x}+i\hat{y})e^{i(k_2z-\omega t)}
$$
$$
B_T(z,t) = \frac{k_2}{\omega}E_{0T}(-i\hat{x}+\hat{y})e^{i(k_2z-\omega t)}
$$

Then I apply boundary conditions in [itex]z=0[/itex].
[itex]B^\perp = 0[/itex] and [itex]E^\perp = 0[/itex] so I only parallel conditions left
$$
E^\parallel_1 - E^\parallel_2 = 0
$$
and
$$
\frac{1}{\mu_1}B^\parallel_1 - \frac{1}{\mu_2}B^\parallel_2 = K_{free} \times \hat{n}
$$

Griffiths in 9.4.2 says that [itex]K_{free} = 0[/itex], but I'm not sure if its still true with perfect conductor. For [itex]E[/itex] I have
$$
(\hat{x}+i\hat{y})E_{0T} + (\hat{x}-i\hat{y})E_{0R} = (\hat{x}+i\hat{y})E_{0T}
$$
and for [itex]B[/itex]
$$
(-i\hat{x}+\hat{y})\frac{1}{\mu_1v_1}E_{0T} + (-i\hat{x}-\hat{y})\frac{1}{\mu_1v_1}E_{0R} = (-i\hat{x}+\hat{y})\frac{k_2}{\mu_2\omega}E_{0T}
$$

which need to be solved, but I'm not sure if I treated polarization right …
 
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  • #2
For point 2 I can only think of that the charge density and surface current will appear on the conductor due to the wave, but I'm not sure how to calculate it.
 

Related to EM wave with circular polarization interferes with conductor

1. What is circular polarization?

Circular polarization is a type of electromagnetic wave in which the electric field vector rotates in a circular motion as the wave propagates through space. It is characterized by both an amplitude and phase component.

2. How does an EM wave with circular polarization interfere with a conductor?

When an EM wave with circular polarization encounters a conductor, the changing electric field induces a current in the conductor. This current, in turn, generates its own electromagnetic field that interferes with the incident wave, resulting in changes to the polarization and amplitude of the wave.

3. What is the effect of circular polarization on conductors?

The interference of an EM wave with circular polarization on a conductor can cause changes in the conductivity and surface currents of the material. This can lead to energy losses and affect the overall performance of the conductor.

4. Can circularly polarized EM waves be used in communication systems?

Yes, circular polarization is commonly used in communication systems such as satellite transmissions and wireless networks. It allows for better signal reception and reduces the impact of interference from other sources.

5. How is circular polarization different from linear polarization?

The main difference between circular and linear polarization is the orientation of the electric field. In circular polarization, the electric field rotates in a circular motion, while in linear polarization, the electric field is confined to a single plane. Additionally, circular polarization has a more complex polarization state compared to the simpler linear polarization state.

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