01-08-2012, 10:06 AM
DESIGN & ANALYSIS OF SLOTTED ANTENNA
[attachment=29780]
ANTENNA:
Antenna is a device used in wireless communication.
Anteena is used to convert electrical energy into electromagnetic waves and vice versa.
At sender,ELECTRICAL ENERGY convert to EM waves.
At reciever,EM waves convert back to the ELECTRICAL ENERGY.
Antennas are of following types:
Wire Antennas
Microstrip Antennas
Reflector Antennas
Travelling Wave Antennas
Aperture Antennas: One of most important antenna of this type is SLOT ANTENNA.
SLOT ANTENNA:
And the hole cut from the metal sheet will work as a complentry dipole to the slot in the metal sheet.
These two complementry dipole and the slot in the metal will have identical antenna parameters.
But the polarisation pattern for both will be different.
If slot has horizontal polarisation pattern then dipole will have vertical polarisation.
Slot antenna work at frequency 300 MHz and 24GHz.
WORKING:
Slot antenna work on Babinet’s principle.
This principle relates the radiated fields and impedance of an aperture or slot antenna to that of the field of its dual antenna.
The field pattern of slot is excatly identical in shape as that of dipole with E and H interchanged.
If the field pattern for slot is vertical then field pattern for the dipole will be horizontal and vice versa.
A voltage source is applied across the short end of the slot antenna.
This induces an E-field distribution within the slot, and currents that travel around the slot perimeter, both contributed to radiation.
The dual antenna is similar to a dipole antenna. The voltage source is applied at the center of the dipole.
So that the voltage source is rotated.
So that E changed into H and vice-versa.
Now concerning about the working:
A longitudinal slot cut into the wall of a waveguide interrupts the transverse current flowing in the
wall, forcing the current to travel around the slot, which induces an electric field in the slot.
The position of the slot in the waveguide determines the current flow.
A waveguide is a very low loss transmission line. It allows propagation of signals to a number of smaller antennas (slots).
NEED OF SLOT ANTENNA:
Slot antenna is basically designed in order to increase the BANDWIDTH.
Since it is essential requirement of communication to increase bandwidth.
For any communication system,
So in order to increase the bandwidth,the gain of the system will fall.That is a drawback of using slot antenna.
To overcome this drawback the gain of system will be reduced to a limit so that the response of the system should not deteriorate.
So the function of a system in communication can be varied accordingly by changing the operating frequency within a reasonable range.
Range is from 1 GHz to 3 GHz.
MICROSTRIP ANTENNA:
Microstrip antennas are planar resonant cavities that leak from their edges and radiate.
Microstrip antenna can withstand tremendous shock and vibration environments.
In its most basic form, a Microstrip patch antenna consists of a radiating patch on one side of a dielectric substrate which has a ground plane on the other side.
The patch is generally made of conducting material such as copper or gold and can take any possible shape. The radiating patch and the feed lines are usually photo etched on the dielectric substrate.
Slot antanna can be made by etching a slot in dielectric substrate and radiation of em waves occur by giving proper feed to antenna.
SIMULATION:
Simulation is basically a procedure to implement a real thing virtually in order to increase the accuracy and to reduce cost.
Software used for simulation of the patch is IE3D.
IE3D is a acknowledged product from ZEALAND SOFTWARE.
[attachment=29780]
ANTENNA:
Antenna is a device used in wireless communication.
Anteena is used to convert electrical energy into electromagnetic waves and vice versa.
At sender,ELECTRICAL ENERGY convert to EM waves.
At reciever,EM waves convert back to the ELECTRICAL ENERGY.
Antennas are of following types:
Wire Antennas
Microstrip Antennas
Reflector Antennas
Travelling Wave Antennas
Aperture Antennas: One of most important antenna of this type is SLOT ANTENNA.
SLOT ANTENNA:
And the hole cut from the metal sheet will work as a complentry dipole to the slot in the metal sheet.
These two complementry dipole and the slot in the metal will have identical antenna parameters.
But the polarisation pattern for both will be different.
If slot has horizontal polarisation pattern then dipole will have vertical polarisation.
Slot antenna work at frequency 300 MHz and 24GHz.
WORKING:
Slot antenna work on Babinet’s principle.
This principle relates the radiated fields and impedance of an aperture or slot antenna to that of the field of its dual antenna.
The field pattern of slot is excatly identical in shape as that of dipole with E and H interchanged.
If the field pattern for slot is vertical then field pattern for the dipole will be horizontal and vice versa.
A voltage source is applied across the short end of the slot antenna.
This induces an E-field distribution within the slot, and currents that travel around the slot perimeter, both contributed to radiation.
The dual antenna is similar to a dipole antenna. The voltage source is applied at the center of the dipole.
So that the voltage source is rotated.
So that E changed into H and vice-versa.
Now concerning about the working:
A longitudinal slot cut into the wall of a waveguide interrupts the transverse current flowing in the
wall, forcing the current to travel around the slot, which induces an electric field in the slot.
The position of the slot in the waveguide determines the current flow.
A waveguide is a very low loss transmission line. It allows propagation of signals to a number of smaller antennas (slots).
NEED OF SLOT ANTENNA:
Slot antenna is basically designed in order to increase the BANDWIDTH.
Since it is essential requirement of communication to increase bandwidth.
For any communication system,
So in order to increase the bandwidth,the gain of the system will fall.That is a drawback of using slot antenna.
To overcome this drawback the gain of system will be reduced to a limit so that the response of the system should not deteriorate.
So the function of a system in communication can be varied accordingly by changing the operating frequency within a reasonable range.
Range is from 1 GHz to 3 GHz.
MICROSTRIP ANTENNA:
Microstrip antennas are planar resonant cavities that leak from their edges and radiate.
Microstrip antenna can withstand tremendous shock and vibration environments.
In its most basic form, a Microstrip patch antenna consists of a radiating patch on one side of a dielectric substrate which has a ground plane on the other side.
The patch is generally made of conducting material such as copper or gold and can take any possible shape. The radiating patch and the feed lines are usually photo etched on the dielectric substrate.
Slot antanna can be made by etching a slot in dielectric substrate and radiation of em waves occur by giving proper feed to antenna.
SIMULATION:
Simulation is basically a procedure to implement a real thing virtually in order to increase the accuracy and to reduce cost.
Software used for simulation of the patch is IE3D.
IE3D is a acknowledged product from ZEALAND SOFTWARE.