Symmetry plane of Mician μWave

A bandpass filter consist of coaxial resonators and dielectric resonators. In order to saving computation time, symmetry plane should be used. Due to the mode nature, magnetic-plane and electric-plane must be applied to coaxial and dielectric resonators respectively, but there is an error occured:"Please check connecting cutoff frequency!".
How to deal with this problem, would you please give me some advices?

Thanks in advance!

Mode Matching connects two or more adjacent discontinuities using transmission line equations for describing the propagation of modes on uniform transmission lines between the discontinuities. The number of modal input and output ports is identical for a uniform lossless transmission line, and so is the number of modes. Furthermore, because of this the number of ports (=accessible modes) at the output of the first discontinuity must equal the number of ports (=modes) at the second discontinuity. Otherwise the transmission line will have a different number of ports at its input than it has at its output and the whole Mode Matching concept falls apart.

When you create a brand new uWave Wizard project, you will have to set the maximum modal cutoff frequency (=cutoff frequency of the highest order mode considered at the ports of elements) as well as symmetry conditions (H-plane, E-plane) in the Project Settings pop up window. If throughout building your project you start deviating from these conventions (i.e. changing your symmetry conditions because you just now remembered that a design incorporating a T-junction cannot have both the H-plane AND E-plane symmetry you applied when designing your individual filters), the modes at some of the element ports will be different for adjacent elements and you will get the error message you posted.

A temporary fix is to open the schematic of the top level or main circuit, then click on Edit ==> Edit all elements of a project ==> Symmetry and apply the appropriate symmetry conditions. Usually this will have to be done every time you re-open your project, hence it makes sense to think about symmetry planes before defining your Project Settings.

A little hint for diplexers and such: Define proper symmetry conditions for the diplexer application, then -if applicable- temporarily overwrite them with H-plane AND E-plane symmetry as described above when creating and optimizing the individual filters (makes them optimize much faster) and revert back to the proper symmetry after connecting the filters to the junction.

I have applied these methods successfully for decades (even before uWave Wizard hit the market) and they are guaranteed to work.

ExHughesGuy, thank you so much for your reply!