Antenna help

[Mica188]

Hi,

I'm new in electronic circuit. I'm working with NEC code to figure out how to analysis antenna. I want some suggestions from you guys where I can start with some simple designe of antenna that I can understand how it works and anaylses? Another question is what is the different if I exicte the antenna with a rectangular pulse, a sinusoidal, another shape of pulse? Where can I find this information?

Thanks,

Mica

 

[VEBill]

Start with a dipole and a single frequency (sin wave).

Any other waveform is broadband.

 

[Mica188]

Thanks,how can I modelling this? I using NEC code and I a saw something in the moldelling like excitation "EX" the antenna? Where I can find some complet examples using this code?

Thanks again,

Mica

 

[VEBill]

I 'got my feet wet' with NEC using the EZ NEC demo.

Ref:

http://www.eznec.com

http://www.eznec.com/demoinfo.htm

It has a nice user interface that makes it perfectly simple to input an antenna geometry, visualize the antenna, and then run the NEC. The EZNEC demo has a 20 element limit, but that is more than enough for a simple dipole. Once you see what is going on, then you can use other NEC software that is more powerful, but still freeware. Or you could buy the full-up EZNEC...

I don't know much about 'excitation'. I just used it to check several frequencies one at a time.

 

[VEBill]

BTW - there is a forum on Eng Tips called:
"Antenna & Propagation Engineering"

More applicable to this subject...

(See you there.)

 

[Mica188]

Thanks,

Mica

 

[bob98009]

The ARRL has good handbooks on antennas. Antennas and loudspeaker systems behave very much alike. The really big engineer in the sky has done some very interesting and strange this in this universe. The business of antenna design borders on witchcraft. use test equipment! wishful thinking does not work in this field. used rf generators are not very expensive, tuners have signel level meters on them usually in the AVC line, if you look around there are all kinds of things that will help you do polar plots,etc.