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btb4198
Antenna Theory Regular
Joined: 19 May 2011
Posts: 20
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 Posted: Sun May 22, 2011 8:18 pm Post subject: 2.4 Ghz receiving antenna |
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| I have designed a 2.4 Ghz receiving antenna. Do I need a Narrow (Single Frequency) Band Pass Filter after the antenna to filter out noise or does the antenna only work for 2.4 Ghz? |
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admin
Site Admin
Joined: 03 Jan 2007
Posts: 247
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| Posted: Mon May 23, 2011 5:09 am Post subject: |
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The receiver you use should already have any necessary filters built into it.
As for whether copper wires will work as transmission lines: no, the characteristic impedance will vary wildly. You'll need to keep the transmission line length to under 1-2 cm (0.1 wavelengths) or you should use some RF transmission line cable (such as a 50 Ohm coaxial cable). See the transmission line tutorial for more info.
Also, try to keep all your posts on this topic to a single thread, it will make the discussion more coherent. |
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btb4198
Antenna Theory Regular
Joined: 19 May 2011
Posts: 20
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| Posted: Mon May 23, 2011 12:42 pm Post subject: |
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do most receiver have a built into op amp ?
I mean can they really run off 7.1950E-8 [watts]? |
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Schubert
Antenna Wizard
Joined: 08 Apr 2009
Posts: 161
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| Posted: Tue May 24, 2011 4:05 am Post subject: |
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Most receivers do have some sort of low-noise amplification. I'm not sure what the gain of the amplifiers are though.
7.19e-8 W sounds low, but it is not. Note that wifi receivers having a sensitivity of -70 dBm is not uncommon. This is -100 dB, which is 10^-10 W. So you actually have more than 100 times enough power. |
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