GB798534A - Improvements in or relating to balanced mixing arrangements for micro wave transmission - Google Patents

Abstract

798,534. Waveguides. TELEFONAKTIEBOLAGET L. M. ERICSSON. Nov. 23, 1956 [Dec. 23, 1955], No. 35949/56. Class 40 (8). [Also in Group XL (c)] A balanced microwave frequency-changer comprises a pair of rectifiers symmetrically disposed in a waveguide and fed with a symmetrical wave from the first source and a non- symmetrical wave from the second. In one embodiment two crystal rectifiers 11, 12, Fig. 1, are located side by side across a waveguide 10, to the end 21 of which is applied a signal wave of TE 10 mode : the guide is tuned by means of a screw 13. The wave is converted to the TD 20 mode by means of a plate 14 screening half the waveguide and the TE 10 mode is suppressed by means of a plate 15 arranged along the longitudinal axis. The other end of the waveguide is closed by a sliding plunger 16, and the local oscillator energy is introduced as a wave of TE 10 mode by means of a coaxial cable 17. An iris diaphragm 18 is interposed in the path to the rectifiers 11, 12 while the space between the plates 14, 18 is filled with a dielectric material. In a second embodiment, the rectifiers 11, 12, Fig. 2, are symmetrically located in a cavity 20 and fed with local oscillations 171 in TE 10 mode introduced by means of a coaxial cable 17. The signal wave is introduced in TE 10 mode 211 at a suitably dimensioned opening 21; the cavity 20, however, is dimensioned and the projecting portion # so adjusted-a movable piston may be provided-as to transform this wave to the TE 20 mode 212. In a further embodiment (Fig. 3, not shown) the oscillator energy is introduced into the waveguide via a single coaxial cable, while the signal is fed in at spaced points over a branched cable, the two branches of which differ in path length by half a wavelength at the signal frequency.