Synthesis of a waveguide field-converter

The paper describes the synthesis of a device that converts an incident field into an outgoing field by means of a high-q reentrant cavity whose left and right walls have a small and varying transparence. By a suitable choice of shape and transparence, the left wall is matched with the field incident on the left, while the right wall is matched with the field outgoing on the right; the waveguides, situated on the left and on the right, can be different. Attention is given to the excitation of the cavity, and the frequency dependence of the fields is determined.