Arrays of point sources

n Elements Uniform Linear Arrays of point sources

Geometric series

CASE 1:- n Elements Uniform Linear Arrays of point sources – BROADSIDE ARRARY

For example Let /2 ;

= 60 or 120

(𝝓𝒎𝒂𝒙 )𝒎𝒊𝒏𝒐𝒓=𝐜𝐨𝐬−𝟏{± 𝝀(𝟐𝒎+𝟏)𝟐𝒏𝒅 }

For example Let /2 ;

Then

if m=1

Thus +41.4 , -41.4 are the 4 minor lobe maxima of the array of 4 Isotropic sources, in phase, spaced /2 apart.

CASE 2:- n Elements Uniform Linear Arrays of point sources – END-FIRE ARRAY

Same Equation of Normalize resultant Field Pattern

For an array to be end fire, the phase angles is such that makes the maximumradiation in the of array i.e. Thus for an array to be and or 180

Thus +75.5 & -75.5 are the 4 minor lobe maxima of the array of 4 Isotropic sources, 180 deg out of phase, spaced /2 apart.

For example if n=4, d= /2,

NOTE:- Here the complementary angle , as has been used in broadside case, is not required. Because the beam width of a end fire array is larger than broadside.

Broadside array antenna

Endfire array antenna

Parasitic array antenna

Collinear array antenna