Dolph Cehbychev, High number of elements

Hi all,
I have a question, I am trying to use the D-Chebyshev distribution for a network, but the matter is that I have a really High number of antenna,
and what I see is that with this number, the dolph Cheb is not stable, so can any one tell me (or give a reference) why the DC distrib is not stable for a high number of antennas.

thanks in advence and best regards.

Hi,

you have many elements, but exactly ?

it is instable if you use a direct approach (till 40 elements in double precison it works). This is beacuse the close formula has products of exponential and factorial number that becames quckly very intractable.

You need a factorization scheme to make this stable (tenth of thousands of elements !).

have alook at ..//web.tiscali.it/antenna_software e download the demo-program you need.

bye.

Hello,
I agree with you I noted that for a number of 40 antennas per dimension ( becasue I am working with a 2D array) it became instable.
I am working with 5 thousand elements.

thnls a lot for ur reply
best regards.

Hello,

but what kind of side lobe topology are you looking for ?

if you have a "separable" distribution you have a side lobe level at the requested level only on the two main cuts and outside of them lover level.

With other techniques you can have all the lobes at the same level !

let me know what array lattice you have and what you want achieve.

bye.