Double Ridge to Quad Ridge transition

Hi, I need to design double ridge to quad ridge transition. But, I have 2 double ridges, which are used for double polarization in quad ridge waveguide. How can I achieve transition?

you need to convert the two linear polarizations into one polarization. Some sort of mode converter. If the two polarizations are not coherent, u could just take off the two polarizations to two coax connectors, and power combine them.

But the problem is that: This Quad Ridge WG will be used for high power application and the frequency is high. There is no connector that can handle the power according to connector manufacturers. Therefore, I need to get the signal from amplifier which has double ridge waveguide end and then couple them.