Dipole moment of small circular antenna - only magnetic?

In summary, when extending from linear dipole antennas to small circular antennas, the expression for the magnetic dipole moment (M1) is often mentioned, but not the electric dipole moment (E1). This is because the current in a circular antenna is azimuthally symmetric, meaning that the effect of the electric dipole moment is cancelled out, leaving only the magnetic dipole moment.
  • #1
fhc6791
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When making an extension from linear dipole antennas to small circular antennas, I am only coming across expressions for a magnetic dipole moment (as opposed to having just an electric dipole moment for a linear dipole antenna). The expression being:
m = πr2I at its peak

The above expression makes perfect sense and is not the problem, rather why only mention a magnetic dipole moment (M1) and no electric dipole moment (E1). Shouldn't it have one also? Or does its azimuthal symmetry (φ dependence) cancel out the effect, leaving only a magnetic dipole moment?

Thanks in advance. I would appreciate any insights!
 
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  • #2
Okay, the more I am really looking at this, I realize that yes, the current is azimuthally symmetric. Sorry to answer my own question!
 

Related to Dipole moment of small circular antenna - only magnetic?

1. What is a dipole moment of a small circular antenna?

The dipole moment of a small circular antenna is a measure of its strength and direction of the magnetic field. It is defined as the product of the current flowing through the antenna and the area of the loop that the current flows through.

2. How is the dipole moment of a small circular antenna calculated?

The dipole moment of a small circular antenna can be calculated using the formula μ = Iπr2, where μ is the dipole moment, I is the current flowing through the antenna, and r is the radius of the loop.

3. What factors affect the dipole moment of a small circular antenna?

The dipole moment of a small circular antenna is affected by the current flowing through the antenna, the radius of the loop, and the material of the antenna. The orientation and position of the antenna in relation to the magnetic field can also affect the dipole moment.

4. How does the dipole moment of a small circular antenna affect its performance?

The dipole moment of a small circular antenna is directly proportional to its radiation efficiency, which is a measure of how much of the radiated energy is converted into electromagnetic waves. A higher dipole moment results in a stronger and more efficient antenna.

5. Can the dipole moment of a small circular antenna be changed?

Yes, the dipole moment of a small circular antenna can be changed by adjusting the current, loop radius, or material of the antenna. The orientation and position of the antenna can also be altered to change its dipole moment and performance.

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