You need to study electromagnetics for this. You can study Tx line without EM like I did because it is all about phasors. If you accept the phasor concept without knowing how it comes from the solution of a differential equation, it is doable.....I did it. Do you mean those TE waveguide? Waveguide is a different story, you really need to know EM, it is not even covered in undergrad EM class.
You can always skip EM and higher math and get on with the electronics. That's what I did when I was a RF engineer. I just study the 2 port parameters, phasors, Smith Charts and did quite a bit of RF designs. When you deal with Tx lines, you really need to know the Smith Chart inside out. You learn to think in Smith Chart. All the impedance transformation, source and load matching, stability of the circuit are all done with Smith Chart. I used to joke about I am dancing on the Smith Chart.
Get the Microwave Engineering by David Pozar, it cover a lot of transmission line stuff you need. You can skip the first chapter of EM and just study it. Make sure you work with the Smith Chart......A LOT!!!! I tried to "see" how the Smith Chart trace move with components in my head. In RF, you really do not "see" how the circuit behave like in the normal transistor or analog circuits you study in those transistor or op-amp books. It is like training yourself a different way of thinking and seeing. You'll be surprised a lot of RF engineer is not very good with Smith Chart and resort of copying application circuit given by the manufacturers.
If you find Pozar too hard, get the Radio Frequency and Microwave Electronics by Matthew M. Radmanesh. This is the easiest book I've seen to get you feet wet into RF and tx lines. Then you study Pozar.
But ultimately, you should go the hard way, study Differential Eq., EM. I actually studied ODE, PDE and EM afterwards and find out how much I missed even though I successfully designed in RF.