I am practising questions from old tests for an upcoming exam on EM fields and waves. I came across this question which has me confused. I'm not sure where to start.
A lossless TL of length l and characteristic impedance of Z_0 has its ends joined together forming a loop as shown below. Find the input impedance Z_in.
Is this an open circuit termination? How is the TEM wave travelling in this circuit. This circuit looks bizarre compared to the typical TL questions that I see.