TYPES OF ANTENNA

Jun 17 • Notes • 24064 Views • 3 Comments on TYPES OF ANTENNA

TYPES OF ANTENNA :

BABINET’S PRINCIPLES OF COMPLEMENTARY ANTENNA :

The complementary impedance can be found by using  Babinet’s Principles . It states when a screen has a opening that is added to complementary structure and a field lies behind it , then the additional value equals to a field  where  screen is absent . The main problem with this equation is that the screen must be thin to wavelength given . Or modes begin from fields fringing and are no longer negligible if the screen is not thin in the type of antenna .

HORN ANTENNA :

In this type of antenna consists of a flaring metal like a horn to help the radio waves to travel in a beam . In this type the horns are used as antennas and they mostly behave like feed horns for larger structures like for example  parabolic antenna . The main advantage is that they can operate over a wide range because of absence of no resonant elements . It is mostly used because of its simple  construction .

                                                                  Figure of horn antenna

PARABOLIC REFLECTOR ANTENNA :

It is a type of antenna a parabolic reflector and a curved surface of sectional shape to direct radio waves . The most common form is shaped similar to a dish antenna or parabolic disc . Its operation is similar to flash light reflector and helps in direct radiation in narrow beam . The main advantage is that they can create narrowest bandwidths . It is mostly used in radar antennas .

                                                      Figure Parabolic Reflector antenna

SLOT ANTENNA :

The main advantage of slot antenna is its design , robust nature , its size and simple to use .  It uses PC board technology . It has a metal surface usually like a flat plate with a slot or hole . Radio magnetic waves are radiated in similar way like dipole antenna . This type of antennas are mostly used in UHF and Microwave .They are also preffered in radar  antennas .

                                                                          Figure of slot antenna

FOLDED DIPOLE ANTENNA :

In radio telecommunication , it is the most simple and very widely used antenna class . It consists of the metal wires and rods which are conductive . Either the transmitter or the receiver is connected to each side of feedline .It follows the monopole antenna and the Rabbit Ears is a good example of this type of antenna . It is the simplest type of antenna from theory point of view.

YAGI UDA ARRAY :

It is also called as Yagi Antenna . The Yagi Antenna is a directional antenna mostly consisting of a dipole ana a folded dipole . This is mostly reffered to as beam antenna which have very high gains . This type of antenna uses narrow bandwidth , very useful for various communication bands . The operation depends on electromagnetic interaction between parasitic elements .

                                                             Figure Yagi uda antena

LENS ANTENNA :

The Lens antenna are mostly used in metering and radar equipments and it works in centimeter wavelength range consisting of a proper lens and a feed .  There are two types of lens antenna

  1.  ACCELERATING LENS :  it is made up of shaped metal sheets .
  2. DECELERATING LENS : low quality homogenous dielectrics are used in its construction .

The surface of the lens is zoned , and hence the weight and dimension reduces .

TURNSTILE ANTENNA :

It is a set of two dipole antennas . It looks very similar to a turnstile when placed horizontally and the antenna acts directionaly in right angle to its plane when  placed vertically . This same principle is followed by Yagi and Long periodic .

V – ANTENNA :

In this type of antenna the conductors are arranged in V – shape along with a balanced line at top . It is also called as Vee Antenna .  The v-shape antenna the two side of a dipole are perpendicular to each other . It is mostly used in areas which have very limited space and this less space does not really have any effect on its performance . Amateur Radio stations mostly use Inverted vee antennas .

MICROSTRIP ANTENNA :

It has two dimensional physical geometry and hence it is easy to design and inexpensive to manufacture .  They are mostly used in UHF . The microstrip antennas has high polarization diversity and can be used for multiple feed points .

                                                        figure of microstrip antenna

RHOMBIC ANTENNA :

A broadly directional antenna having high frequency is termed as Rhombic antenna . The main advantages is that it has stable input impedance and pattern of radiation .  It is a simple to use and effective transmitting antenna .

BEVERAGE ANTENNA :

This antenna is mostly used in high frequencies because it has long wire receiving antenna . It is also used by amateur radio . A large amount of space is required because these antennas provide excellent directivity .

QUESTIONS AND ANSWERS :

QUE > WHAT IS FOLDED DIPOLE ANTENNA ?

ANS >  In radio telecommunication the most simple and  widely used antenna class . It consists of the metal wires and rods which are conductive in nature  . The transmitter or the receiver is connected to each side of feedline .It follows the monopole antenna and the Rabbit Ears is a good example of this type of antenna . It is the simplest type of antenna from theory point of view.

QUE > WRITE SHORT NOTE ON RHOMBIC ARRAY ?

ANS > It is a  broadly directional antenna having high frequency is termed as Rhombic antenna . The main advantages is that it has stable input impedance and pattern of radiation .  It is a simple to use and very effective transmitting antenna.

GATE Syllabus-

1. Gate Syllabus for Electronics and Communication 2014

2. Gate Syllabus of Engineering Science 2014

IES Syllabus-

1. IES Syllabus for Electronics and Telecommunication

2 IES Syllabus for General Ability

 

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