Even and Odd mode resonance frequencies

Is there any way to discriminate even and odd mode resonance frequencies (in ads or cst) without solving complicated equations? If so, plz explain it. Current density can help us?
Regards,

In general, symmetry boundaries can be a very nice way to create an artificial mode filter in a structure. For example, if I take a rectangular 2D waveguide, cut if in half, and assign the plane of cut with a PEC boundary (and assign the correct impedance multiplier), then I will only be solving for odd modes that exist in the overall structure.

Hope this helps

Consider the following image:

There are 3 Res. Freq. I want to know which one is related to odd or even mode.

In an empirical way, you can slightly change the gap in the two coupled lines, and that will shift the resonances that depend mostly on odd mode excitation. You can then keep the gap constant, and change the line width of the two coupled lines, which will change the resonance of the even mode more.

thank you for your hint biff44.but
why will gap change shift odd mode, while the width change shift even mode resonance freq.?
would you explain it more precisely,please?