Math Problem Statement

describe the polarization of a wave with phasor electric field given by Eˉ=2(a^y​−ja^z​)e−jk0​x( V/m)

Solution

The given phasor electric field is:

E=2(a^yja^z)ejk0xV/m\mathbf{E} = 2 (\hat{a}_y - j \hat{a}_z) e^{-jk_0 x} \, \text{V/m}

where:

  • a^y\hat{a}_y and a^z\hat{a}_z are the unit vectors in the yy- and zz-directions, respectively.
  • jj is the imaginary unit (i.e., j2=1j^2 = -1).
  • k0k_0 is the wavenumber, related to the wavelength λ\lambda by k0=2πλk_0 = \frac{2\pi}{\lambda}.
  • The time dependence is implicit (assuming a harmonic time dependence ejωte^{j\omega t}).

Step-by-step breakdown:

  1. Electric Field Components: The electric field has two components:

    • 2a^yejk0x2\hat{a}_y e^{-jk_0 x} in the yy-direction (real component),
    • j2a^zejk0x-j2\hat{a}_z e^{-jk_0 x} in the zz-direction (imaginary component).
  2. Interpretation of Components: The yy-component is real, and the zz-component is imaginary, implying a phase difference of π2\frac{\pi}{2} between the two components. Since the zz-component is multiplied by jj, it lags the yy-component by 9090^\circ.

  3. Polarization: Since the electric field has non-zero components in both the yy- and zz-directions and the two components have a phase difference of 9090^\circ, the wave is circularly polarized.

    Specifically, the wave is left-hand circularly polarized (LHCP) because the zz-component lags behind the yy-component by 9090^\circ. For a left-hand circularly polarized wave, the electric field vector rotates counterclockwise in the plane of the wave's propagation (if viewed from the direction of propagation).

Summary:

The wave represented by the given electric field is a left-hand circularly polarized wave, propagating in the xx-direction. The electric field vector rotates in the yy-zz plane as the wave moves forward.

Do you want further details or have any questions?

Here are 5 related questions you might find useful:

  1. What is the difference between left-hand and right-hand circular polarization?
  2. How is circular polarization different from linear polarization?
  3. What is the significance of the wavenumber k0k_0 in wave propagation?
  4. How does the phase difference between components affect wave polarization?
  5. What is the general form of the electric field for an elliptically polarized wave?

Tip: Circular polarization occurs when two perpendicular components of the electric field have the same magnitude and a phase difference of ±90\pm 90^\circ.

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Math Problem Analysis

Mathematical Concepts

Electromagnetism
Phasor Representation
Wave Polarization

Formulas

E = 2 (a_y - j a_z) e^{-jk_0 x}
Phase difference = π/2

Theorems

Circular Polarization
Wavenumber Relation k0 = 2π/λ

Suitable Grade Level

Undergraduate Physics