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The parabolic shape is a special concave reflecting surface that concentrates wave energy. It is used to collect the parallel waves from an extremely distant source.
There is a special location called the focal point where the wave receiver (detector) is placed. Waves arriving from any other direction (angle) will concentrate away from this receiver and are ignored.
You can also emit energy at the focal point. The reflected energy will stay concentrated (parallel) over extreme distances.
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What is the difference between directed antenna and parabolic dish?
about 40 db about 40 db
Why we use patch antenna in communication?
because patch antenna are used in order to achieve higher gain small dimensions, light weight, slim size and easy manufacturing as compared with parabolic dish or other antenna's
What kind of shape is the primary mirror of a reflecting telescope?
The name of this type of instrument is derived from the fact that the primary mirror reflects the light back to a focus instead of refracting it. The primary mirror usually has a concave spherical or parabolic shape, and, as it reflects the light, it inverts the image at the focal plane.
If antenna is passive than how can it add gain?
Antennas provide so called passive gain, which means it comes from particular shape of the antennaThe gain of an antenna is a passive phenomenon - power is not added by the antenna, but simply redistributed to provide more radiated power in a certain direction than would be transmitted by an isotropic antenna. If an antenna has a gain greater than one in some directions, it must have a gain less than one in other directions, since energy is conserved by the antenna.SOURCE: wikipedia.com
How is the radiation pattern of a parabolic reflector antenna plotted?
The paraolic antenna has a high degree of "directivity" compared to many other antennas. That gives these puppies big gain. But they need to be pointed in the "right" direction to work well. This antenna design is used in many radar (and other microwave) applications, as well as in satellite communication. And is has a home with radio astronomers, too, but they're usually listening instead of transmitting. It has a parabolic reflector, and some kind of support for the feedhorn, sub-reflector or whatever is at the focus. We're talking about a transmission antenna here, so there will be some kind of feed assembly to put the signal onto the parabolic reflector to "send out" or transmit that signal. How do we test it? It's so simple that you're not gonna believe it. The reflector can be modified a bit to "broaden" the primary lobe of the radiated signal either horizontally or vertically. But let's work with a simple parabolic reflector. Imagine a parabolic antenna that is fixed so it's stationary. Let's look at which way the signal goes. There are two variables to assess when plotting the radiated pattern, and they are usually referenced to the "direction" or "directivity" of the antenna, or the direction of what might be termed the primary lobe or beam of the radiation. Put another way, there is one direction that is the "center of the beam" for this antenna, and once we establish this line, we reference to it. Something is either left or right of the line by "x" number of degrees, or something is above or below the line by "y" degrees. You gonna put this up on a pole and walk around measuring radiated power at different points left or right of, or above or below the beam? Remember I said this was ease? Put the antenna on a stand and make it point horizontally. Make that stand like a heavy duty lazy susan so the whole thing rotates. Hook up a signal generator to it, and put in the desired operating frequency. (The signal generator won't be generating high power, and that's okay. A milliwatt isn't even necessary for the test.) We're now ready to transmit, and that's our test antenna setup. Step off a hundred meters (or whatever) and set up a receiving antenna (pointed at the antenna under test and at the same level). Hook up a receiver to the receiving antenna so that signal strength can be measured. Turn on your equipment and rotate the turntable slowly. As the turntable rotates, it causes the antenna being tested to "sweep" the horizon with its little output signal. As it moves around, the receiver will be getting more and more and more signal, or less and less and less signal, depending on whether the test antenns is sweeping toward or away from the receiver. With a computer hooked up to the receiver (via a handy IEEE bus) and doing some recording, a relative signal strength can be plotted. Presto! You've got a 360o plot of the relative output signal strength. All you have to do is raise you receiving antenna a touch, and then point it down a tiny bit so it's aimed directly at the test antenna. Then turn the test antenna and record for another 360o view at a bit high of beam center. Keep moving up the receiving antenna in steps, realigning it, and testing a circle. Do this for a bunch of vertical levels above beam center. Then come back and do it again for a bunch of levels below beam center. You're done! The trick is to set up the test antenna on a turntable and point it flat out and level with the horizon, and then to begin with a receiving antenna level with and pointed directly at the test antenna. The turntable does most of the work, and it makes it easy. The work is in raising or lowering the receiving antenna in calculated steps and realigning it at each step to point it directly at the test antenna. By the time the test crew get finished, the computer can plot a nice 3D chart (in the form of a thick cylinder with the test antenna at the center that will demonstrate the performance of that test antenna. Piece of cake. The paraolic antenna has a high degree of "direcitivity" compared to many other antennas. That gives these puppies big gain. This antenna design is used in many radar and in satellite communication applications, as well as having a home with radio astronomers. It has a parabolic reflector, and some kind of support for the feedhorn, sub-reflector or whatever is at the focus. We're talking about a transmission antenna here, there will be some kind of feed assembly to put the signal onto the parabolic reflector to "send out" or transmit the signal. How do we test it? It's so simple that you're not gonna believe it. The reflector can be modified a bit to "broaden" the primary lobe of the radiated signal either horizontally or vertically. But let's work with a simple parabolic reflector. Imagine a parabolic antenna that is fixed so it's stationary. Let's look at which way the signal goes. There are two variables to assess when plotting the radiated pattern, and they are usually referenced to the "direction" or "directivity" of the antenna, or the direction of what might be termed the primary lobe of the radiation. Put another way, there is one direction that is the "center of the beam" for this antenna, and once we establish this line, we reference to it. Something is either left or right of the line by "x" number of degrees, or something is above or below the line by "y" degrees. You gonna put this up on a pole and walk around measuring radiated power at different points left or right of, or above or below the beam? Remember I said this was ease? Put the antenna on a stand and make it point horizontally. Make that stand like a heavy duty lazy susan so the whole thing rotates. Hook up a signal generator to it, and put in the desired operating frequency. (The signal generator won't be generating high power, and that's okay. A milliwatt isn't even necessary for the test.) We're now ready to transmit, and that's our test antenna setup. Step off a hundred meters (or whatever) and set up a receiving antenna (pointed at the antenna under test and at the same level). Hook up a receiver to the receiving antenna so that signal strength can be measured. Turn on your equipment and rotate the turntable slowly. As the turntable rotates, it causes the antenna being tested to "sweep" the horizon with its little output signal. As it moves around, the receiver will be getting more and more and more signal, or less and less and less signal, depending on whether the test antenns is sweeping toward or away from the receiver. With a computer hooked up to the receiver (via a handy IEEE bus) and doing some recording, a relative signal strength can be plotted. Presto! You've got a 360o plot of the relative output signal strength. All you have to do is raise you receiving antenna a touch, and then point it down a tiny bit so it's aimed directly at the test antenna. Then turn the test antenna and record for another 360o view at a bit high of beam center. Keep moving up the receiving antenna in steps, realigning it, and testing a circle. Do this for a bunch of vertical levels above beam center. Then come back and do it again for a bunch of levels below beam center. You're done! The trick is to set up the test antenna on a turntable and point it flat out and level with the horizon, and then to begin with a receiving antenna level with and pointed directly at the test antenna. The turntable does most of the work, and it makes it easy. The work is in raising or lowering the receiving antenna in calculated steps and realigning it at each step to point it directly at the test antenna. By the time the test crew get finished, the computer can plot a nice 3D chart (in the form of a thick cylinder with the test antenna at the center that will demonstrate the performance of that test antenna. The output pattern should look like a long, skinny teardrop. Piece of cake.
Why the parabolic antenna has parabola shape?
Parallel rays, such as those from a very distance source, are focussed by a parabolic antenna so that they all meet at the focus of the parabola. This results in a stronger signal.
How do dogs' ears shapes help them hear?
The shape acts like a parabolic antenna, focusing sound into the ear from a larger surface area. Simples.
What are the material is used manufacturing Parabolic reflector antenna?
A parabolic reflector antenna is made of fiberglass or metal (usually aluminum).
What type of antenna is used for satellite communication?
parabolic
Why might a parabolic reflector horn type microwave antenna be preferable to a parabolic dish type microwave antenna?
The reflector horn type antenna has greater "side lobe" rejection, directionality and sensitivity (efficiency) than a dish type.
Is there a platinum in parabolic disc antenna?
It would be a waste of precious metal if there was.
Why antena is in parabolic form?
A: For the same reason a heater is parabolic to reflect heat, For the antenna the opposite is true to focus the incoming waves
What uses are there for parabolic mirrors?
Parabolic mirrors are formed in a dish like shape, the purpose of it's shape is to transmit the electromagnet waves. For example when using a microwave or watching a television, it is through electromagnet radiation that make it possible to function. Television receives the signals via the satellite dish, the satellite dish acts as the parabolic mirror.
What is the difference between directed antenna and parabolic dish?
about 40 db about 40 db
What is meant by parabolic?
It means in the shape of a parabola.
What is a spherical dish antenna required for satellite tv reception?
The parabolic antenna is really not an antenna at all - but a collector/reflector, which catches and concentrates RF (radio frequency) into a tiny antenna mounted above the dish, pointed into the dish. Since satellites transmit at very high frequencies (microwave), the actual antenna can be shorter than one inch. To strenghen the signal and make aiming the antenna at the satellite easier, the parabolic reflector picks up a wider area of RF.
Does shape of the antenna effect the magnetic field?
Yes for instance a dipole will have a doughnut shape field and a directional like a yagie will have a long teardrop shape field at the front end and a shorter teardrop field at the rear and some smaler fields sideways and a parabolic disc wil have a very long teardrop shape field
