On Sat, 11 Dec 2010 16:56:34 +0000, frankieNrosie
wrote:

freq=5.8GHz
i'm wanna design multiband antenna, not sure about impedance..

If you want one frequency, then it would imply one band.

If you want multiband, then you need to give us the other frequencies.

73's
Richard Clark, KB7QHC

the other freq, not specific yet..
i use the diode as the switch to reconfigure the freq..later on i will upload the figure of proposed antenna

On Sun, 12 Dec 2010 12:18:11 +0000, frankieNrosie
wrote:

If you want one frequency, then it would imply one band.

If you want multiband, then you need to give us the other frequencies.

the other freq, not specific yet..

Then how do you know it is multiband?

Your most specific request is for a folded dipole at one frequency.
From end-to-end it will be slightly less than 1/2 wavelength long at
that frequency.

Now, if you add another frequency, your folded dipole will need to be
1/2 wavelength long at that frequency.

Obviously to be "multiband" your folded dipole cannot be both lengths
at the same time. The requirment for the fold of the folded dipole is
obscure. A fan dipole would work for multiband.

i use the diode as the switch to reconfigure the freq..later on i will
upload the figure of proposed antenna

I have not the vaguest idea what that is about. "The diode"?

73's
Richard Clark, KB7QHC

diode is use as a switch to vary the length of the driven element..
so, if i got many length of the driven element, thus i'll have many freq..
do u understand me?

On Tue, 14 Dec 2010 06:19:35 +0000, frankieNrosie
wrote:

i use the diode as the switch to reconfigure the freq..later on i will
upload the figure of proposed antenna-

I have not the vaguest idea what that is about. "The diode"?

diode is use as a switch to vary the length of the driven element..
so, if i got many length of the driven element, thus i'll have many
freq..
do u understand me?

I understand what you write, but not why you choose this arrangement.
I can guess many configurations, but your goal is obscure.

Inventive to say the least.

Conventional antenna design already has passive solutions for your
active element requirement and they stand the chance of reducing the
risks inherent in putting a diode into an antenna structure for
switching its length.

73's
Richard Clark, KB7QHC