Since now I am using UPML for waveguide termination due to the simplicity and uniformity in the equations that describe it. But there is some cost, namely larger number of operations and double the number of field components (main and auxillary). Moreover, there is a limitation regarding the wave impendance that has to be know before simulation. So CPML comes to mind for a better and more robust solution.
What are, according your to your opinion, pros and cons about these two types of PML. In CPML is there nessecary to know ,before the simulation, the wave impendance. And how the conductivity is scaled inside the absorbing layer.Moreover, in UPML we have to know wave impendance before simulation (in order to be used in the conductivity scaling). But, what if the excitation can't tell us many information about the wave that it will be grown and/or propagate inside the structure.
Too many questions, but thank you in advance!