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Circular Polarized Antenna Measurement

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azremi

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Hello guys,

Do you have any idea on how to measure the radiation pattern of circulary polarized antenna..?

Any important parameters that need to consider/ take into account if we want to design a 'good' antenna with circular polarization?

Looking forward to hearing comments and suggestions :)

TQ
 

dowjones

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may I suggest that you take a look to any antenna text book including a measurements chapter?. I suggest antennas by Kraus, but there are also specific antenna measurement textbooks, as these:

GE Evans, "Antenna Measurement Techniques", Artech House, Boston, 1990

Microwaves Antenna Measurements. Hollis JS, Lyon TJ and Clayton L. Scientific Atlanta.
1970 (1983)

(Antenna Handbook by Lo also includes one chapter)

You can measure with a linear probe in an anechoic chamber, measuring amplitude and phase, and then composing the results in right hand and left hand polarizations, or you can measure with two CP probes (RH and LH).

Important parameters: difficult to answer, depends on your requirement (gain, beamwidth, axial ratio...). If your main interest is circular polarization, then your design parameter is axial ratio (at the angular range speified), but your design must also meet the requirements you have on gain, beamwidth, sidelobes,....

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    azremi

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azremi

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Hello Dowjones,

Thanks for your reply. Really need to get some books and see information about it.

So then by using a linear probe in an anechoic chamber, do we need to divide the measurement into two steps? Meaning measure the amplitude on right hand first, followed by left hand..and then compose the results?

The important parameters: Yes, usually we need to look at the gain and beamwidth of AUT, but I'm not so sure on the axial ratio...How can we know that we get the best result for the axial ratio? How to explain this..?

What value of axial ratio that usually need to be consider as to say that the antenna is really good in CP?

TQ
 

dowjones

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hi,

attached find some information on polarization measurements. it is taken from the scientific atlanta antenna book


check this :




rgdz
 

    azremi

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dowjones

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finally, here (**broken link removed**) you can find an excellent antenna measurement chapter (chapter 8, I think), collected by this professor. probably it will help you to clarify some doubts

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    azremi

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