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7rots51
Joined: 17 May 2002
Posts: 1427
Helped: 14
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 03 Oct 2008 13:59 Reflective Open and Reflective Short SWITCH |
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what is the difference between reflective open and reflective short RF switches?
what are the applications for each of them ?
for selection between 2 anttena for a transceiver which of them should be used and why?
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kspalla
Joined: 19 Aug 2008
Posts: 848
Helped: 140
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04 Oct 2008 8:45 Reflective Open and Reflective Short SWITCH |
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To my knowledge reflective switch are not preferred as it may cause problems.
By theory both short and open are same in behavior. (magnetic or electric)
The selection is depend on how you would like to process this reflected energy.
Let me think more on selection of antenna based on
1) reflections caused due to clutter
2) not in the direction of GSM tower etc.
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FvM
Joined: 22 Jan 2008
Posts: 5161
Helped: 767
Location: Bochum, Germany
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04 Oct 2008 9:07 Re: Reflective Open and Reflective Short SWITCH |
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| I wonder if this is a practical or a theretical question. Practically most RF switches are reflective open. In some applications, you would prefer absorptive switches. Antenna switching is mostly using simple reflective switches, I think.
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7rots51
Joined: 17 May 2002
Posts: 1427
Helped: 14
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04 Oct 2008 13:52 Re: Reflective Open and Reflective Short SWITCH |
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this is a practical question.
I want to select 1 of 2 antenna at a time and send 2W power to it,which switch topology is better? Ref Open or Ref Short?
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FvM
Joined: 22 Jan 2008
Posts: 5161
Helped: 767
Location: Bochum, Germany
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04 Oct 2008 14:18 Reflective Open and Reflective Short SWITCH |
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| kspalla already stated that they are effectively identical in behaviour. I understand, that the reflective port is connected to the antenna not in use. The most economical coaxial RF switches are reflective open, I think, there are good for antenna switching.
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biff44
Joined: 24 Dec 2004
Posts: 1835
Helped: 244
Location: New England, USA
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04 Oct 2008 15:25 Re: Reflective Open and Reflective Short SWITCH |
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For 2 watts of power, it probably does not make a difference.
So you have a signal source, a cable, a sp2t switch, and then 2 cables and 2 antennas. The only potential problem is if the two antennas are close to each other AND the cable length to the unselected antenna resonates at the transmit frequency. It might change the transmitted antenna radiation pattern.
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04 Oct 2008 15:25 Ads |
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kspalla
Joined: 19 Aug 2008
Posts: 848
Helped: 140
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07 Oct 2008 8:47 Reflective Open and Reflective Short SWITCH |
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Hi,
Reflective short or open? this can also be decided based on application like
1) you need to increase ground spread then go for short. this also helps you in current sensing.
2) you need to increase the volume for your antenna where two antennas may be stacked then go for open.
Other conditions and applications may be explored.
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