- #1

TheArun

- 25

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I have a few doubts regarding antenna radiation and propogation. Kindly look into it and clarify.

Consider a Hertzian dipole antenna,

DOUBT # 1. Generally, when the power is mentioned for an antenna elements such as the power dissipated across radiation resistance(R

P radiated = (1/2)I

Doubt:

1. Generally, Power equation is P = I

2. Does the half term come from the equation of power across load allowing ac power i.e.,

P = V

By taking the peak value of V and I and denoting V in terms of I it changes to, P = (1/2)I

a) Current, without mentioning explicitly is always considered to be an 'ac current peak value which is in phase with voltage'

and

b) If that is the case, does that also mean that Hertzian dipole or a current element that radiates as an antenna can only be made using a ac current and not dc current?

DOUBT#2: Consider a electric field having θ and φ component i.e.,

E = E

where,

E - electric field vector

Eθ - electric field component in θ direction and Eφ - Electric field compo in φ direction

So my doubt is what actually is this Eθ(or Eφ) which is a scalor along θ direction:

Is it a angle in θ direction ie say 30 deg in θ direction OR is it a distance?

Consider a Hertzian dipole antenna,

DOUBT # 1. Generally, when the power is mentioned for an antenna elements such as the power dissipated across radiation resistance(R

_{rad})P radiated = (1/2)I

^{2}R_{rad}Doubt:

1. Generally, Power equation is P = I

^{2}Resistance, but according to the above equation only 1/2 of the power across the radiation resistance is actually radiated. Is it a case of power lost and where?2. Does the half term come from the equation of power across load allowing ac power i.e.,

P = V

_{rms}* I_{rms}cos@By taking the peak value of V and I and denoting V in terms of I it changes to, P = (1/2)I

^{2}R. If that is the case does that mean that,a) Current, without mentioning explicitly is always considered to be an 'ac current peak value which is in phase with voltage'

and

b) If that is the case, does that also mean that Hertzian dipole or a current element that radiates as an antenna can only be made using a ac current and not dc current?

DOUBT#2: Consider a electric field having θ and φ component i.e.,

E = E

_{θ }a_{θ}+ E_{φ}a_{φ}where,

E - electric field vector

Eθ - electric field component in θ direction and Eφ - Electric field compo in φ direction

So my doubt is what actually is this Eθ(or Eφ) which is a scalor along θ direction:

Is it a angle in θ direction ie say 30 deg in θ direction OR is it a distance?

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