Ports are defined in the '''Observables''' section of the navigation tree. You can define any number of ports equal to or less than the total number of sources in your project. If you have N sources in your planar structure, then N default ports are defined, with one port assigned to each source according to their order on the navigation tree. Note that your project can have mixed gap and probes sources as well as active lumped element sources on PEC and slot traces or vias. You can also couple ports together to define coupled transmission lines such as coupled strips (CPS) or coplanar waveguides (CPW).
[[Image:Info_icon.png|40px]] Click here to learn more about the '''[[Common_Excitation_Source_Types_in_EMGlossary_of_EM.Cube%27s_Simulation_Observables_%26_Graph_Types#The_Port_Definition_Observable Port_Definition_Observable | Port Definition Observable]]'''.
[[Image:Info_icon.png|40px]] Click here to learn more about '''[[Common_Excitation_Source_Types_in_EM.Cube#Modeling_Coupled_Ports | Modeling Coupled Ports]]'''.