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jabidof
Joined: 25 Jul 2003
Posts: 80
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 09 Jun 2004 11:07 change the radiation pattern |
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Hello everybody,
I have the following issue to solve. Imagine you have a dipole or PIFA antenna for a given UHF frequency. Now, depending on the position of the feeding point you'll choose, you'll get different input impedance, i.e. theoretically from 0 to infinity [Ohms].
1. Does the radiation pattern of the antenna change with a change in the feeding point position?
2. Considering we're always power-matched to the input impedance of the antenna, does the efficiency of the antenna change with a change in the feeding point position?
Thanks for your appreciated help  ,
Jpc
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jyfx
Joined: 07 Jun 2004
Posts: 26
Helped: 1
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20 Jun 2004 14:51 antenna radiation pattern matching |
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| position is very important ,or you can get low gain
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jyfx
Joined: 07 Jun 2004
Posts: 26
Helped: 1
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20 Jun 2004 14:52 Antenna radiation pattern |
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| you can find some theary in some book of antenna
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Google
AdSense
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20 Jun 2004 14:52 Ads |
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ruth
Joined: 02 Jun 2004
Posts: 6
Location: China
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24 Jun 2004 13:50 Antenna radiation pattern |
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| the structure determines the radiation pattern ,so ,when you change the feeding point ,the pattern doesn't change ,but the vswr changes as well as the efficiency
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plasma
Joined: 20 Dec 2001
Posts: 577
Helped: 40
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24 Jun 2004 22:25 Re: Antenna radiation pattern |
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in printed antennas or the same structure the feeding point change
the current and the modes so it change also the pattern like center feed
and end feed in patch. in some ways it change also the polarization from
linear to circular.
PL
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zorro
Joined: 06 Sep 2001
Posts: 380
Helped: 47
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24 Jun 2004 23:47 Antenna radiation pattern |
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Consider an extreme case: two antennas (e.g. two pieces of wire) with very weak mutual coulpling or no coupling at all. This can be considered “an antenna” (a single “antenna”; why not?). Obviously, the radiation pattern, the matching, the efficiency, the polarization, etc. change if you change the feeding point between one to the other.
Regards
Z
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