What kind of impedance does a half wavelength transmission line present to the source when the line is open at the far end?

Unlike a quarter-wavelength line, a half-wavelength transmission line acts as an impedance repeater or a 1:1 transformer. The impedance presented at the source end is exactly the same as the impedance at the far end of the line. In this scenario, the far end is open, meaning it has an infinite or very high impedance. Because the half-wave line simply repeats this impedance across its 180-degree electrical length, the source will also see a very high impedance. Answers suggesting a very low impedance or characteristic impedance are incorrect because the half-wave line mirrors the termination rather than transforming or inverting it.