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  Topic: Need help identifying this PCB antenna
Schubert

Replies: 3
Views: 9362

PostForum: Questions Related to Antenna Theory   Posted: Tue Aug 12, 2014 9:31 pm   Subject: Need help identifying this PCB antenna
That can be a distributed inductor (i.e. adds parallel inductance at feed to cancel out increased capacitance due to wrapping dipole close to ground plane). So technically it is an IFA.

An IFA is ...
  Topic: Need help identifying this PCB antenna
Schubert

Replies: 3
Views: 9362

PostForum: Questions Related to Antenna Theory   Posted: Mon Aug 11, 2014 10:24 pm   Subject: Need help identifying this PCB antenna
That's just a piece of crap dipole antenna. One side is the main ground plane (i.e. the ground of the board) and the other side is that meandered wire to fit in the space provided
  Topic: Feeder SWR & power loss
Schubert

Replies: 22
Views: 45146

PostForum: Questions Related to Antenna Theory   Posted: Fri Jul 25, 2014 11:15 pm   Subject: Feeder SWR & power loss
Your conclusions aren't valid.

You can't forget all of transmission line theory to reach those conclusions. 50 ohm receiver powers a 50 ohm load, it doesn't matter how you measure it, reflected ...
  Topic: 8 Shape Magnetic Loop
Schubert

Replies: 1
Views: 6361

PostForum: Questions Related to Antenna Theory   Posted: Wed May 28, 2014 11:26 pm   Subject: 8 Shape Magnetic Loop
It depends on the frequency. If you're in near field though you almost certainly want the simple small circular loop
  Topic: The corner reflector size relative to the wavelength
Schubert

Replies: 1
Views: 5732

PostForum: Questions Related to Antenna Theory   Posted: Wed May 28, 2014 11:26 pm   Subject: The corner reflector size relative to the wavelength
If your corner reflector is 180 degrees, then it is not a corner. It is just a flat plate. In that case, lambda/4 (quarter wavelength) should be good
  Topic: log periodic V boom angle
Schubert

Replies: 1
Views: 6361

PostForum: Questions Related to Antenna Theory   Posted: Wed May 28, 2014 11:25 pm   Subject: log periodic V boom angle
It's all optimization. Decreasing that angle would likely affect the bandwidth somewhat, but would probably still be ok.
  Topic: Oops... Cell phone screw up
Schubert

Replies: 4
Views: 10056

PostForum: Questions Related to Antenna Theory   Posted: Wed May 28, 2014 11:24 pm   Subject: Oops... Cell phone screw up
If you don't have a network analyzer, there is no way to reliably tell how critical it is.

From my experience (and I've done antennas on a lot of phones), it isn't critical to the mm level (i.e. ...
  Topic: Oops... Cell phone screw up
Schubert

Replies: 4
Views: 10056

PostForum: Questions Related to Antenna Theory   Posted: Tue May 27, 2014 9:48 pm   Subject: Oops... Cell phone screw up
The thickness of the copper doesn't matter. If you didn't screw up the feed (there is usually a coaxial connector to the main board) then you can replace the copper you tore off and it will likely fu ...
  Topic: ANTENNA FERRITE SHIELDING
Schubert

Replies: 2
Views: 8529

PostForum: Questions Related to Antenna Theory   Posted: Mon May 19, 2014 11:23 pm   Subject: ANTENNA FERRITE SHIELDING
Shielding is not the right word.

This only applies for NFC antennas (near field antennas that aren't really antennas). The ferrite increases the "effective separation" to the metal behin ...
  Topic: Equivalent Cirtcuit
Schubert

Replies: 1
Views: 6031

PostForum: Questions Related to Antenna Theory   Posted: Fri Apr 11, 2014 9:38 pm   Subject: Equivalent Cirtcuit
There are a few ways depending on what type of antenna it is.

If you have a simple half-wavelength dipole antenna, you can assume a resistor of 70 Ohms and some inductance (impedance is about 73 + ...
  Topic: Antenna Array
Schubert

Replies: 3
Views: 10497

PostForum: Questions Related to Antenna Theory   Posted: Fri Apr 11, 2014 9:35 pm   Subject: Antenna Array
Yes it is possible to do 360 scan. You can adjust the weights of the antenna array for maximum reception towards any specific angle. This will require a 2-dimensional array though.

It is also pos ...
  Topic: wire gsm umts antenna
Schubert

Replies: 1
Views: 6749

PostForum: Questions Related to Antenna Theory   Posted: Sat Mar 29, 2014 7:27 pm   Subject: wire gsm umts antenna
You have to cut it for the longer wavelength (800 MHz). Then make it super fat, like a bowtie antenna, and it will probably cover both bands.

http://www.antenna-theory.com/antennas/wideband/bowt ...
  Topic: Citatión
Schubert

Replies: 1
Views: 6324

PostForum: Questions Related to Antenna Theory   Posted: Sat Mar 08, 2014 7:45 pm   Subject: Citatión
No problem - its always ok to site the web. Just put website name with URL, title of page referenced, and date accessed.
  Topic: Help with antenna on portable radio worn on hip.
Schubert

Replies: 1
Views: 7478

PostForum: Questions Related to Antenna Theory   Posted: Sat Mar 08, 2014 7:40 pm   Subject: Help with antenna on portable radio worn on hip.
Welcome to the world of wearable antennas. It sucks.

In principal, the loop antenna should perform better when placed on the body (near field should be magnetic field dominant, which is less affec ...
  Topic: Log Periodic Tooth antenna
Schubert

Replies: 1
Views: 6651

PostForum: Questions Related to Antenna Theory   Posted: Wed Jan 29, 2014 3:25 am   Subject: Log Periodic Tooth antenna
r1, r2, etc is just a subscript (i.e. the inner radius of the first tooth, the inner radius of the 2nd tooth)

they are geometrically related per the equation on the listed page

r_(n+1)/r_n = k
 
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