ludwig 3 coordinate
As far as I'm aware, topics similar to this one have already appeared twice before (https://www.edaboard.com/ftopic73543.html & https://www.edaboard.com/viewtopic.php?p=994796#994796) and using the information provided in the latter topic I used the Ludwig 3 co-ordinate system to obtain the Ludwig 3 vertical and horizontal plots of my farfield results.
Since this coordinate system realigns the farfield such that the z' axis is now aligned with the main lobe of the farfield (which is along the x-axis of my structure) and the y' axis is aligned with the polarisation vector (which is along the y-axis of my structure), this means that the E-plane of my antenna is now in the y'z' plane (in the Ludwig-3 coordinate system). The H-plane was originally in the xz plane, so in the Ludwig-3 coordinate system is now in the x'z' plane.
This means that to obtain the co-cross polar isolation for the E-plane I was just obtaining the difference between the Ludwig-3 vertical (co-polarisation) and Ludwig-3 horizontal (cross-polarisation) farfield results in the y'z' plane. While, to obtain the co-cross polar isolation for the H-plane I was just obtaining the difference between the Ludwig-3 vertical and Ludwig-3 horizontal farfield results in the x'z' plane. Is this a valid method for obtaining the co-cross polar isolation in the E and H planes do you think? Or is there another method I should be using? Thanks for your help with this :)
at all in any plane,there are co and x pol ,avoiding using e walls and h walls in ur structure if it is symmetric.for example in ur far field results,u see abs,phi,theta,ok. if phi is co pol then theta is x pol.another way to use ludwig 3 instead of spherical coordinates.i hope that help
Many thanks for your reply abdoeng, my structure is horizontally polarised since the E-phi component is generally of a much greater magnitude than the E-theta component, I was thinking that I could use this to obtain the co- and cross-polarisations, but do you know (or does anyone else know) whether the method I used to obtain the cross-polar isolation using the Ludwig-3 coordinate system is valid? Thanks :)
Hey guys (and girls of course!), I was just wondering if any among you have any idea whether the method I used to obtain the cross polar isolation for my Vivaldi antenna structure is correct? It's just that I'm still not 100% certain of my results and I don't think the help files or previous topics here on this matter go into very much detail about how to do this. Many thanks in advance :)