How to Build an antenna?

[MAY]

Hi all,

1) can a wire antenna produce a circularly polarized radiation?
2)I need to build a home made antenna with the following specs:
the frequency of operation is between f=8-12GHz, BW=.1f, elliptical polarization with an axial ratio between 1 and 2 (in other words, as circularly polarized as possible).
the directivity>15 dBi, gain>12 dBi.

Thanks,
MAY

[noid]

I'm sure someone here can help you, or you can find other online resources. But, if you are seriously interested in learning about antennas I highly recommend the ARRL Antenna book.

http://www.amazon.com/exec/obidos/tg...19952?v=glance

[philoT]

Are you doing this to reduce the multipath? It is a bit difficult to compute the filters you'd need to make this work. http://www.wifi-plus.com/pages/13/pa...=1098368628531 has a lovely analysis of antenna types. The multi-pole antennae perform better than the circular-pole ones. Lucky for us because they are very easy to build!

Like so...

| = vertical
- = horizontal

a | recieved on a - will have almost no signal. A solution is to have two elements on the antenna, one | and one - so you get a +

You might also experiment with metal disks or something that looks like a fan.

Hope this helps. I would be interested to hear about the outcome of any experiments!

[Floydr47]

Hi all,

1) can a wire antenna produce a circularly polarized radiation?
2)I need to build a home made antenna with the following specs:
the frequency of operation is between f=8-12GHz, BW=.1f, elliptical polarization with an axial ratio between 1 and 2 (in other words, as circularly polarized as possible).
the directivity>15 dBi, gain>12 dBi.

Thanks,
MAY

This may be of some help to you http://www.6mt.com/1296tech.htm

They have manuals and parts at that site.

[n8tiveR00K]

Hi all,

1) can a wire antenna produce a circularly polarized radiation?
2)I need to build a home made antenna with the following specs:
the frequency of operation is between f=8-12GHz, BW=.1f, elliptical polarization with an axial ratio between 1 and 2 (in other words, as circularly polarized as possible).
the directivity>15 dBi, gain>12 dBi.

Thanks,
MAY

Are you talking about an Omni directional antenna?

[n8tiveR00K]

Hi all,

1) can a wire antenna produce a circularly polarized radiation?
2)I need to build a home made antenna with the following specs:
the frequency of operation is between f=8-12GHz, BW=.1f, elliptical polarization with an axial ratio between 1 and 2 (in other words, as circularly polarized as possible).
the directivity>15 dBi, gain>12 dBi.

Thanks,
MAY

This book is pretty good, but basic. I have it and I like it. Explains a lot. Check out the first chapter.


http://www.wifi-toys.com/mo-wifitoys-chapter01.pdf