Non-destructive ΔH measurement of LPE/YIG wafer using terminated straight waveguide

A method is described for measuring the ΔH of LPE/YIG wafers non-destructively, based on homodyne monitoring of the reflected wave in a terminated straight waveguide. The wafer is placed on the coupling iris of the wall of waveguide. An equation is given for the equivalent circuit of ferromagnetic material at resonance, and a comparison made between theory and experiment. The effects of shape and dimension of coupling irises are discussed. A method is described for measuring 2"φ wafer by setting a copper plate with a window behind it.