how design LPDA in MMANA software

does anyone can explain how to make a LPDA antenna in MMANA?

or does anyone have a file LPDA in MMANA software for my reference... please share it..

MMANA is not a design program, but an analysis program. As such, you can't use it to design a log-periodic antenna. You will have to find a method from elsewhere, and use that to calculate the lenghts and spacings of the elements, and then check the performance in MMANA-GAL.

You could try the trial version of Antenna Magus. I know the full version has the facility to design a log periodic antenna, but I'm not sure about the trial version. But the full version is not worth the nearly 8000 Euros cost in my opinion.

There are some pretty simple formula around for designing log periodic antennas. See for example:

"Design of log-periodic dipole antennas" by Peixeiro. You can then get that into MMANA-GAL and analyse it. Unfortunately, MMANA-GAL's optimiser is no good for wide band antennas. I don't believe you can optimise for bandwidth.


BTW, I just looked up log periodic on Wikipedia and as usual with almost any antenna topic, it is written by radio hams and is done very poorly (BTW, I'm a ham myself, G8WRB). But the talk page actually has some useful information about the design. I've not checked it, but at first glance it looks like I've seen in books before, where there is a constant ratio in length of two adjacent elements and the same constant ratio in the spacing between two adjacent elements.

Talk:Log-periodic antenna - Wikipedia, the free encyclopedia

Let be L(i) the length of the i-th element, and L(i-1) the length of its precedent,

and let be D(i), D(i-1) their respective distances to the vertex. Then

(1) L(i) / L(i − 1) =

(2) D(i) / D(i − 1) =

I think you want to make the longest element a half-wave on the lowest frequency of interest, but check the paper by Peixeiro for more information.

For a design file for MMANA-GAL, why not look in the examples? There is one at least one. See:

C:\MMANA-GAL_Basic\ANT\VHF beams\TV Log Yagi-UHF.maa

BTW, for reasons I don"t understand, the professional version of MMANA-GAL does not ship with the examples! So I keep both the basic and the Pro versions on my machines.

Dave