antenna-theory.com Forum Index antenna-theory.com
Antenna Theory
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

Search found 265 matches
antenna-theory.com Forum Index
Author Message
  Topic: Fractal Sheet Metal Antenna
bigSteve

Replies: 1
Views: 6827

PostForum: Questions Related to Antenna Theory   Posted: Fri Apr 10, 2015 5:00 pm   Subject: Fractal Sheet Metal Antenna
Your problem is a good one, but unfortunately....you can only estimate things. There's so much reflection/multipath/whatever that will make it tough to figure out the radiation pattern. Add on top o ...
  Topic: Helix Antenna Design for a GPS receiver
bigSteve

Replies: 4
Views: 10063

PostForum: Questions Related to Antenna Theory   Posted: Fri Apr 10, 2015 4:57 pm   Subject: Helix Antenna Design for a GPS receiver
This sounds like a stupid homework problem
  Topic: Spiral, 1/2 wave dipole -- probable radiation pattern?
bigSteve

Replies: 1
Views: 7451

PostForum: Questions Related to Antenna Theory   Posted: Sat Sep 06, 2014 7:49 pm   Subject: Spiral, 1/2 wave dipole -- probable radiation pattern?
That antenna is basically a short dipole antenna, so the radiation pattern will be similar to a short dipole (sin[theta] pattern). Think of a dipole with the arms wrapped up in spirals so it is short ...
  Topic: History of the Horn Antenna
bigSteve

Replies: 1
Views: 6321

PostForum: Questions Related to Antenna Theory   Posted: Sat Sep 06, 2014 7:46 pm   Subject: History of the Horn Antenna
Hmm...interesting. I thought Horns weren't around till the 30s. I guess they were using higher frequencies than I knew of in the 1890s.
  Topic: antenna element radius vs length
bigSteve

Replies: 1
Views: 6840

PostForum: Questions Related to Antenna Theory   Posted: Sat Sep 06, 2014 7:45 pm   Subject: antenna element radius vs length
Basically fat dipoles are better for your driven element in yagi antennas. There's not a huge variance though as you get the dipole fatter - basically resonance goes from 0.49 lambda (infinitely thin ...
  Topic: Correlation
bigSteve

Replies: 1
Views: 6601

PostForum: Questions Related to Antenna Theory   Posted: Thu Aug 21, 2014 9:46 pm   Subject: Correlation
That doesn't make any sense. Why would increased mutual coupling of antennas decrease their correlation? It would increase it. You must think about what you are doing
  Topic: Advice/help with electromagnet project, please?
bigSteve

Replies: 1
Views: 6702

PostForum: Questions Related to Antenna Theory   Posted: Tue Aug 05, 2014 4:53 am   Subject: Advice/help with electromagnet project, please?
It's fine to post here. Some notes:

- you need d.c. current to flow in a loop to make an electromagnet
- you won't have anything of an electromagnet unless you have a bunch of loops of wire aroun ...
  Topic: RHCP Turnstile Testing
bigSteve

Replies: 3
Views: 10473

PostForum: Questions Related to Antenna Theory   Posted: Fri Jul 18, 2014 5:55 pm   Subject: RHCP Turnstile Testing
What you are describing is exactly what I would expect from two linearly polarized antennas. I suspect your RHCP antennas aren't really circularly polarized
  Topic: Feeder SWR & power loss
bigSteve

Replies: 22
Views: 45357

PostForum: Questions Related to Antenna Theory   Posted: Wed Jul 09, 2014 3:52 am   Subject: Feeder SWR & power loss
I wonder how you can measure a "standing wave ratio" unless the reflections are already taken into account? Where do you think the standing waves come from if the measurement doesn't alread ...
  Topic: Feeder SWR & power loss
bigSteve

Replies: 22
Views: 45357

PostForum: Questions Related to Antenna Theory   Posted: Sun Jul 06, 2014 9:03 pm   Subject: Feeder SWR & power loss
I read the arrl.org section "Does higher SWR Lead to Lower Power Being Transmitted?" in which he argues that the power is eventually delivered to the antenna.

I've got to tell you, I inte ...
  Topic: Feeder SWR & power loss
bigSteve

Replies: 22
Views: 45357

PostForum: Questions Related to Antenna Theory   Posted: Sun Jul 06, 2014 6:41 pm   Subject: Feeder SWR & power loss
Whoever said "the power is re-reflected towards the antenna again" is full of crap. There is no "multiple reflections in time". The vector network analyzer that measures the refl ...
  Topic: Slot antenna
bigSteve

Replies: 5
Views: 14653

PostForum: Questions Related to Antenna Theory   Posted: Wed Jun 11, 2014 2:09 am   Subject: Slot antenna
You could have 20 dB of polarization mismatch loss. It's tough to estimate the impact of that, it depends on the degree of "purity" of the polarization of your antennas, distance, transmit ...
  Topic: Slot antenna
bigSteve

Replies: 5
Views: 14653

PostForum: Questions Related to Antenna Theory   Posted: Mon Jun 09, 2014 2:39 am   Subject: Slot Antennas
For the slot antenna, what really matters is the perimeter, which should be about 1 wavelength. So if you make a thin slot, it should be about 0.49 lambda (factoring in the width of the slot).

As ...
  Topic: need guidance for designing a triangular patch antenna
bigSteve

Replies: 2
Views: 8436

PostForum: Questions Related to Antenna Theory   Posted: Tue May 13, 2014 6:21 pm   Subject: need guidance for designing a triangular patch antenna
It's pretty simple - just make the longest dimension of the triangle a half-wavelength at the frequency you want it to radiate at. Then move the feed around to get the impedance right
  Topic: Why does a single-feed truncated square patch radiate CP
bigSteve

Replies: 3
Views: 12314

PostForum: Questions Related to Antenna Theory   Posted: Sat May 03, 2014 6:26 pm   Subject: Why does a single-feed truncated square patch radiate CP
Honestly, it is not super clear why cutting the edges creates circular polarization.

You are right on this:
you need 2 orthogonal components for circular polarization, and this can be created with ...
 
Page 1 of 18 Goto page 1, 2, 3 ... 16, 17, 18  Next
All times are GMT
Jump to:  


Powered by phpBB © 2001, 2005 phpBB Group