JECRC UDML COLLEGE OF ENGINEERING
PRACTICAL TRAINING PRESENTATION
ANTENNA AND RADIATION PATTERN
(ALL INDIA RADIO, JAIPUR)
Submitted to :
Presented By :
Kailash Chandra Yadav
Introduction To A.I.R.
Type of Antennas
Pattern Lobe and Beam Width
Key Learning's At Training
INTRODUCTION TO A.I.R.
All India Radio(AIR) is one of the largest radio
networks in the world.
The Bombay station was inaugurated on July
23, 1927, the Kolkata station followed on
August 26, 1927.
AIR was established in 1930 and All India
Radio,Jaipur was established at 9th April
The Satellite Earth station was established at
Around 2,75,000 receiving sets were at the time of
Independence, now there are about 132 million estimated radio
sets in the country.
AIR today having a network of 237 broadcasting centres with 149
medium frequency (MW), 54 high frequency (SW) and 177 FM
The coverage is 91.85% of the area, serving 99.18% of the
people in the largest democracy of the world.
AIR covers 24 Languages and 146 dialects in home services.
SERVING FREQUENCIES IN JAIPUR
Introduction Of Antenna
Antenna is usually a metallic device (as a rod or a
wire) used for radiating or receiving
Transmission - radiates electromagnetic energy into
Reception - collects electromagnetic energy from space
In two-way communication, the same antenna can
be used for transmission and reception
½ Wave Dipole
¼ Wave Monopole
The radiation pattern of antenna is a representation
of the distribution of the power radiated from the
antenna or received to the antenna as a function of
direction angles from the antenna.
It is independent on the power flow direction.
It is usually different for different frequencies and
different polarizations of radio wave radiated /
There are two types of pattern :
Power pattern vs. Field pattern
The power pattern is the calculated and plotted
received power |P(θ, ϕ)| at a constant (large)
distance from the antenna.
The amplitude field pattern is the calculated and
plotted electric (magnetic) field intensity, |E(θ, ϕ)|
or |H(θ, ϕ)| at a constant (large) distance from the
The power pattern and the field patterns are inter-related:
P(θ, ϕ) = (1/η)*|E(θ, ϕ)|2 = η*|H(θ, ϕ)|2
P = power
E = electrical field component vector
H = magnetic field component vector
η = 377 ohm (free-space, plane wave impedance)
Antenna radiation pattern
The 3-D plot of antenna
pattern assumes both
angles θ and ϕ varying,
which is difficult to produce
and to interpret
Usually the antenna pattern is
presented as a 2-D plot, with
only one of the direction angles,
θ or ϕ varies.
It is an intersection of the
3-D one with a given plane
usually it is a θ = const. plane or a
ϕ= const. plane that contains the
Two 2-D patterns
Pattern lobe is a portion
of the radiation pattern
with a local maximum.
Lobes are classified as: 1)
2) Minor lobes
3) Side lobes
4) Back lobes
Half-power beam width (HPBW) is the
angle between two vectors from the pattern’s
origin to the points of the major lobe where
the radiation intensity is half its maximum
First-null beam width (FNBW) is the angle
between two vectors, originating at the
pattern’s origin and tangent to the main beam
at its base.
• A measure of the directionality of an antenna.
• Power output, in a particular direction, compared
to that produced in any direction by a perfect
omnidirectional antenna (isotropic antenna).
• Related to physical size and shape of antenna.
Relationship between antenna gain and effective
4πAe 4πf 2 Ae
G= 2 =
G = antenna gain
Ae = effective area
f = carrier frequency
c = speed of light ( 3X108 m/sec.)
λ = carrier wavelength
The radiation efficiency e indicates how efficiently
the antenna uses the RF power.
It is the ratio of the power radiated by the antenna
and the total power delivered to the antenna
terminals. In terms of equivalent circuit parameters:
Rr + Rl
Antenna array consists of multiple antennas
collaborating to synthesize radiation characteristics
not available with a single antenna. They are able
To match the radiation pattern to the desired coverage
To change the radiation pattern electronically through
the control of the phase and the amplitude of the signal
fed to each element.
To adapt to changing signal conditions.
To increase transmission capacity by better use of the
radio resources and by reducing interference.
Advantages of Antenna Array
Possibilities to control electronically
Direction of maximum radiation
Directions (positions) of nulls
Levels of side lobes
Using standard antennas (or antenna
collections) independently of their radiation
Antenna elements can be distributed along
straight lines, arcs, squares, circles, etc.
A View of Antenna Array
27 antennas along 3 railroad tracks provide baselines
up to 35 km. Radio images are formed by correlating
the signals garnered by each antenna.
KEY LEARNING’S AT TRAINING
Important concepts of communication.
Development of a practical point of view towards
It was a wonderful experience while training in A.I.R.
There is great scope for engineers in the field of
Exposure to practical working conditions will be beneficial
for our career.