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antenna9071
Antenna-Theory.com Newbie
Joined: 17 Jun 2011
Posts: 8
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 Posted: Fri Jun 17, 2011 9:33 pm Post subject: recomendation of antenna type |
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I want to build a antenna of this condition. what type of antenna is recomended? Patch antenna?
*much metal in the environment
*will sit on vehicle for hight speed max 200km/h
*dual band 868Mhz( Rfid),2,45GHz
*smal, max (w*L*H) 5cm*10cm*2cm
*range max 15-20m
*circular polarized |
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bigSteve
Antenna Wizard
Joined: 14 Mar 2009
Posts: 265
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| Posted: Sat Jun 18, 2011 10:04 am Post subject: |
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Can you define much metal in the environment? If it is on a surface, then yes a patch antenna will work as the ground plane more or less will shield it from the metal below the surface. Or if it is a airplane for instance a monopole sticking out of the surface would also work.
Sitting on a moving vehicle is a mechanical/aero concern, not an antenna concern, regardless of the speed.
You don't have much volume there for 868 MHz, you might need a dielectric with permittivity of at least 4 to help get an efficient antenna in that volume.
The max range is more of a receiver/transmitter issue, once that is defined you can determine the required antenna efficiency.
You're probably not going to get good circular polarization so that requirement probably isn't going to happen...... |
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antenna9071
Antenna-Theory.com Newbie
Joined: 17 Jun 2011
Posts: 8
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| Posted: Sun Jun 19, 2011 8:26 pm Post subject: |
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| bigSteve wrote: | Can you define much metal in the environment? If it is on a surface, then yes a patch antenna will work as the ground plane more or less will shield it from the metal below the surface. Or if it is a airplane for instance a monopole sticking out of the surface would also work.
Sitting on a moving vehicle is a mechanical/aero concern, not an antenna concern, regardless of the speed.
You don't have much volume there for 868 MHz, you might need a dielectric with permittivity of at least 4 to help get an efficient antenna in that volume.
The max range is more of a receiver/transmitter issue, once that is defined you can determine the required antenna efficiency.
You're probably not going to get good circular polarization so that requirement probably isn't going to happen...... |
patch antenna is the choise it looks like to be. you say
"You're probably not going to get good circular polarization so that requirement probably isn't going to happen......"
why? |
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bigSteve
Antenna Wizard
Joined: 14 Mar 2009
Posts: 265
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| Posted: Mon Jun 20, 2011 2:12 am Post subject: |
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| Tell me how you plan to get circular polarization |
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