The document discusses different types of antenna arrays, including broadside arrays, end-fire arrays, and binomial arrays. A broadside array consists of half-wave dipoles spaced by half wavelengths that produces a highly directional radiation pattern perpendicular to the array. An end-fire array uses two half-wave dipoles spaced by half a wavelength and radiates in the plane of the dipoles. A binomial array arranges radiating sources according to binomial coefficients to reduce side lobes and optimize directivity.

1. Broadside, End Fire &
binomial array antennas
by
Sushant Burde (B-48)
Vaibhav Deshmukh(B-52)
Rohit Dhongde(B-41)
Pratik Suryavanshi(B-40)

2. Driven Arrays: Broadside
Antenna
 A broadside array is a stacked collinear antenna
consisting of half-wave dipoles spaced from one another
by one-half wavelengths.
 This antenna produces a highly directional radiation
pattern that is broadside or perpendicular to the plane of
the array.
 The broadside antenna is bidirectional in radiation, but
the radiation pattern has a very narrow beam width and
high gain.

3. Broadside Array
 Bidirectional Array
 Uses Dipoles fed in phase and separated by 1/2
wavelength
 Broadside arrays may also b e formed from other types
of elements, such as horns, slots, helixes and polyrods

4. O. Kilic EE 542
4
Radiation Pattern for Arrays
Depends on:
 The type of the individual elements
 Their orientation
 Their position in space
 The amplitude and phase of the current feeding them
 The total number of elements

5. Broadside Arrays
Beam steering by phase variation is possible.

7. broadside array antenna
Figure 14-30: A broadside array.

8. Driven Arrays: End-Fire
Antenna
 The end-fire array uses two half-wave dipoles spaced
one-half wavelength apart.
 The end-fire array has a bidirectional radiation pattern,
but with narrower beam widths and lower gain.
 The radiation is in the plane of the driven elements.
 A highly unidirectional antenna can be created by careful
selection of the optimal number of elements with the
appropriately related spacing.

9. End-Fire Array
 Similar to broadside array except dipoles are fed 180
degrees out of phase
 Radiation max. off the ends

10. End-fire Arrays
 Higher directivity.
 Provide increased directivity in elevation and azimuth
planes.
 Generally used for reception.
 Impedance match difficulty in high power transmissions.
 Variants are:
 Horizontal Array of Dipoles
 RCA Fishborne Antenna
 Series Phase Array

12. End fire arrays
F: End-fire antennas. (a) Bidirectional. (b) Unidirectional.

13. Binomial array antenna
 Binomial array is an array of non-uniform amplitudes
and the amplitude of the radiating sources are
arranged according to the co-efficient of successive
term of the following binomial series and hence the
name

14. Advantages
 To reduce secondary lobes
 2. to optimize them.
 As we increase the array length the directivity
increases and side lobes appear.

15. Pattern multiplication
 Multiplication pattern is the total field pattern of an array
of non-isotropic but similar source
 It is the multiplication of the individual source pattern
and the pattern of an array of isotropic point source
each located at the phase centre of individual sources
having the relative amplitude and phase T
 The total phase pattern is the addition of the phase
pattern of ‘the individual source and that of the array of
isotropic point sources.

16. Principle
 The total field pattern of an array of non-isotropic but
similar sources is the product of the individual source
&The array pattern of isotropic point sources each
located at the phase centre of the individual source and
the array pattern of isotropic point sources each located
at the phase centre of the individual sources having the
same amplitude and phase.