Electron cyclotron absorption (ECA) of electromagnetic radiation at the second harmonic is of interest in Tokamak physics both for plasma heating and current drive, as well as for some diagnostics. Modelling of the linear wave propagation for such problems is usually done by WKB ray tracing, despite the fact that the WKB theory is not strictly valid in the neighbourhood of a resonance, where reflection and mode conversion can occur. Here, we present a full wave analysis of second harmonic ECA and compare it with various ray tracing models. The full wave equation used differs from previous ones in that it is valid even in regimes where significant absorption occurs on scale lengths comparable to the incident wavelength. The resulting analysis allows us to assess the accuracy of ray tracing in describing such problems.
