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  Topic: Cloverleaf Antenna Construction
hagster

Replies: 1
Views: 378

PostForum: Questions Related to Antenna Theory   Posted: Thu Nov 30, 2017 10:17 pm   Subject: Cloverleaf Antenna Construction
Sounds possible to me, but construction would be significantly more difficult.
  Topic: Polarization Loss
hagster

Replies: 1
Views: 683

PostForum: Questions Related to Antenna Theory   Posted: Sun Oct 01, 2017 10:09 pm   Subject: Polarization Loss
Yes reciprocity holds. It is the same if you swap the Tx and Rx.
  Topic: How valuable is a system which can design antenna on its own
hagster

Replies: 3
Views: 1458

PostForum: Questions Related to Antenna Theory   Posted: Sat Aug 19, 2017 7:22 am   Subject: How valuable is a system which can design antenna on its own
I am not aware of a general solution.

Antenna engineers usually rely on there knowledge of prior art as a starting point and build/test/simulate from there.

There is however much more to antenna ...
  Topic: How valuable is a system which can design antenna on its own
hagster

Replies: 3
Views: 1458

PostForum: Questions Related to Antenna Theory   Posted: Fri Aug 18, 2017 7:49 pm   Subject: Re: How valuable is a system which can design antenna on its
I am thinking of making a system which can generate a antenna for a given input radiation pattern, that is, we draw a radiation pattern we desire and the system churns out a antenna design which can a ...
  Topic: Physics behind antennas principle of operation
hagster

Replies: 1
Views: 1282

PostForum: Questions Related to Antenna Theory   Posted: Sun Aug 13, 2017 2:18 pm   Subject: Physics behind antennas principle of operation
This is the best guide I have seen on how antennas work. Its very old, but good.

https://youtu.be/T-SbBlNgUTU
  Topic: Build an ferrite antenna
hagster

Replies: 1
Views: 1857

PostForum: Questions Related to Antenna Theory   Posted: Thu May 11, 2017 8:53 pm   Subject: Build an ferrite antenna
A ferrrite antenna is just a version of a small loop antenna. The ferrite makes the behavior non linear at higher power levels so these antennas are only really useful as receivers. Normally they are ...
  Topic: Antenna design / joining two seperate outputs to one antenna
hagster

Replies: 2
Views: 2268

PostForum: Questions Related to Antenna Theory   Posted: Sat Mar 25, 2017 7:26 am   Subject: Antenna design / joining two seperate outputs to one antenna
Just to add a bit more to my last comment.

Its fairly normal to acheive dual polarisation this way. Although there is a DC short between the 2 feed pins at the operating frequency(looks like 5ghz t ...
  Topic: Antenna design / joining two seperate outputs to one antenna
hagster

Replies: 2
Views: 2268

PostForum: Questions Related to Antenna Theory   Posted: Fri Mar 24, 2017 10:33 pm   Subject: Antenna design / joining two seperate outputs to one antenna
The two antenna ports provide different polarisation. The WiFi router can exploit this using MIMO techniques to increase data capacity. I.e.You have 2 channels with polarisation divesity.
  Topic: how to reduce sidelobes of microstrip array antenna?
hagster

Replies: 2
Views: 2276

PostForum: Questions Related to Antenna Theory   Posted: Thu Mar 09, 2017 8:41 am   Subject: Re: how to reduce sidelobes of microstrip array antenna?
hi guyss,
i have antenna that operates on 28 GHz, which is microstrip array antenna.. and now i want to reduce the sidelobes of the antenna.. do you guys have any suggestion??

You can reduce the ...
  Topic: Cavity Backed Spiral Antenna - LHCP/RHCP
hagster

Replies: 1
Views: 4013

PostForum: Questions Related to Antenna Theory   Posted: Thu Nov 03, 2016 6:39 pm   Subject: Cavity Backed Spiral Antenna - LHCP/RHCP
That will come from an empirical measurement of the polorisation. All it means is that the antennas are not perfectly circularly polarised. That said -26db is pretty good and once you have real world ...
  Topic: 4nec2 and axial ratio of circular antenna
hagster

Replies: 11
Views: 11758

PostForum: Questions Related to Antenna Theory   Posted: Sun Sep 04, 2016 6:28 am   Subject: Re: 4nec2
Hi

One more question if i work with only one source ...what i need to do in 4nec2 that one L is connected in the middle of coaxial cable and other L is connected to gnd of cable .

Thanks

Y ...
  Topic: 4nec2 and axial ratio of circular antenna
hagster

Replies: 11
Views: 11758

PostForum: Questions Related to Antenna Theory   Posted: Sat Sep 03, 2016 4:16 pm   Subject: 4nec2 and axial ratio of circular antenna
I see what they are doing now. One arm is slightly longer and thus slightly inductive. The other arm is shorter and hence slightly capacitive. This should cause the current to lag the voltage in the l ...
  Topic: 4nec2 and axial ratio of circular antenna
hagster

Replies: 11
Views: 11758

PostForum: Questions Related to Antenna Theory   Posted: Sat Sep 03, 2016 9:43 am   Subject: 4nec2 and axial ratio of circular antenna
Ok, so there were a few problems with your model.

1) the feed was across adjacent arms of the X (in an L configuration). Thus the two dipoles were 180 out of phase not 90.
2) The excitation sou ...
  Topic: 4nec2 and axial ratio of circular antenna
hagster

Replies: 11
Views: 11758

PostForum: Questions Related to Antenna Theory   Posted: Sat Sep 03, 2016 1:21 am   Subject: 4nec2 and axial ratio of circular antenna
I will run the model later, but for now just check that you are exciting each dipole with the correct phase. I.e they need to be 90 degrees apart.
  Topic: biquad yagi hybrid antenna [kickstarter]
hagster

Replies: 1
Views: 5290

PostForum: Questions Related to Antenna Theory   Posted: Thu Sep 01, 2016 12:55 pm   Subject: biquad yagi hybrid antenna [kickstarter]
https://www.kickstarter.com/projects/1096577862/the-biquad-yagi-antenna-for-wifi-and-fpv/description

I came across this Kickstarter for the bi-quad yagi antenna and was initially quite sceptical ab ...
 
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