# parasitic array

Post on 07-Dec-2015

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parasitic array antenna,uses and its comparability with the common flashlight

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ARRAYPARASITICPARASITIC ARRAY consists of one or more parasitic elements with a driven element, the amount of power gain and directivity depends on the lengths of the parasitic elements and the spacing between them

THINKOFITTHISWAY

How can this small light bulb illuminate a large room if this said bulb is placed in the center?Of course you need REFLECTORS

However, if a reflector were placed behind the bulb, the space in front of the reflector would be brighter and the space behind the reflector would be dimmer.But, WAIT you can also direct the light to where you wanted to place it using LENS or what we known as DIRECTORS.Thus, the combination of light bulb, reflector and lens can be summed up to a

?How is a flashlight comparable to a parasitic antenna?PARTS

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LENSBULBREFLECTORParasitic elementsDriven elementsWhen the parasitic element is placed so that it radiates away from the driven element, the element is a director. When the parasitic element is placed so that it radiates toward the driven element, the parasitic element is a reflector.OPERATION

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Although we do not usually discuss the gain of a flashlight, we can continue the comparison of an antenna and a flashlight to explain the meaning of antenna gain. Suppose the spot on the wall in front of the flashlight becomes 10 times brighter than it was when only the open bulb was used. The lens and reflector have then produced a 10-fold gain in light. For antennas, the simple half-wave antenna corresponds to the open bulb in the flashlight. Suppose an antenna system concentrates the radio waves so that at a particular point the field strength is 10 times more than it would be at the same distance from a half-wave antenna. The antenna system is then said to have a gain of 10.RAD PATTERN

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UNIDIRECTIONALUNIDIRECTIONALIs it possible to change the radiation pattern of a parasitic array antenna?YES OFCOURSEHOW??????????????????????????Changing the spacing and length can change the radiation pattern so that maximum radiation is on the same side of the driven element as the parasitic element.Finally, its easier to remember properties and parts of a flashlight than the parasitic array antenna. Thus, given all the specifications, a flashlight is comparable to a parasitic antenna