Two infinitesimal dipoles of equal length are equidistant from the origin with their centers lying on the z-axis and oriented parallel to the y-axis- Both are kept apart by a distance of -4- They are excited with currents of equal magnitude but current in dipole 1 at Z -d2 lags the current in dipole 2at Z -d2by 90o in phase- The radiation pattern in yz plane is Diagram

Array factor =cos[12(β dcos θ=ϕ)] here, nbsp; nbsp;β=2πλ,d=λ4,ϕ= π2 Array factor = cos[π4cos θ π4] The normalized field is given by E_n=cosθ cos[π4(co ...

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Antenna Characteristics Parameters (Part 2)

Two infinites...

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Two infinitesimal dipoles of equal length are equidistant from the origin with their centers lying on the z-axis and oriented parallel to the y-axis. Both are kept apart by a distance of $\frac{λ}{4.}$ They are excited with currents of equal magnitude but current in dipole 1 $a t Z = + \frac{d}{2}$ lags the current in dipole 2 $(a t Z = - \frac{d}{2}) b y 90^{o}$ in phase. The radiation pattern in yz plane is

Diagram

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Solution

Array factor $= c o s [\frac{1}{2} (β d c o s θ = ϕ)]$

here, $β = \frac{2 π}{λ}, d = \frac{λ}{4}, ϕ = - \frac{π}{2}$

Array factor = $c o s [\frac{π}{4} c o s θ - \frac{π}{4}]$

The normalized field is given by

$E_{n} = c o s θ c o s [\frac{π}{4} (c o s θ - 1)]$

and the nulls by

$E_{i n} = 0$

$\Rightarrow θ_{n} = 90^{o} a n d 180^{o}$

Option (d) pattern is satisfied.

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Array factor =cos[12(βdcos θ=ϕ)] here, β=2πλ,d=λ4,ϕ=−π2 Array factor = cos[π4cos θ−π4] The normalized field is given by En=cosθ cos[π4(cosθ−1)] and the nulls by Ein=0 ⇒ θn=90o and 180o Option (d) pattern is satisfied.