The synthesis of waveguide band-pass elliptic filters is realized. The thin transverse resonance diaphragms with an aperture in the form of a rectangular window with two metal L-shaped metal ridges are used as resonators of the filter. An equivalent circuit of a resonant diaphragm is proposed. The synthesis results of an elliptic filter for a rectangular waveguide WR137 with a bandwidth of 9,2% and length of 64 mm are presented.