The bending loss in Ge-Ag-Ni waveguide as a function of waveguide radius is disscussed. The advantages of the small-sectional radius waveguide are discribed, and a novel method of RF sputterins for fabrication of hollow waveguides with small diameters is proposed. Finally, some samples have been fabricated using the method and the transmitunces of the samples with different waveguide diameters are presented and compared.