question about equation (4-78) balanis's book

[farshidazhir]

who can prove this equal("Iin=Io*sin(kl/2)") in page of 163 balanis's book ???
thanks

 

[MacGyverS2000]

I'm sure a lot of us can prove it... but why?


Dan
Owner

http://www.Hi-TecDesigns.com

 

[farshidazhir]

this equal is important for change position of feeder in dipole antenna's problems

 

[IRstuff]

So? If you're an engineer, why do YOU need to prove it?

If you're a student, youve come to the wrong place for homework help

TTFN

 

[logbook]

Balanis doesn't seem to give any indication where this equation comes from. Equation 4-78 in section 4.5.5 is just stated. Looking earlier (4.5.1) the current distribution in a finite dipole is again just stated as being sinusoidal. The text does state that the sinusoidal character has been experimentally verified however.

 

[zeitghost]

It's not one of these "it can be shown that" is it?

I well remember one of those that took 3 pages of calculation to get from equation 1.1.45 to equation 1.1.46

Saves the printer a lot of time & paper though.

Otherwise known as "An exercise for the reader".

 

[farshidazhir]

thanks,
if dipole antenna is center-fed=>current distribution is
"Ie=Iosin(k(L/2-+z)) where -L/2<z<L/2" ok?
now if for matching ,feeder is not in center of dipole
what is current distribution now? Ie=?

 

[VEBill]

You can probably assume that the current drops to zero in roughly the same place (*) that the conductor ends. ;-)


[* with maybe 5% 'end effect']

 

[farshidazhir]

thanks VE1BLL but i know it
do you know any formula for this?