GB800056A - Improvements in resonant directional waveguide couplers - Google Patents

Abstract

800,056. Directional couplers for waveguides. MARIE, G. R. P. June 26, 1956 [June 30, 1955], No. 19751/56. Class 40 (8). [Also in Group XL (c)] A directional waveguide coupler comprises rectangular guides 15, 16, Fig. 2, joined by a circular guide 18 the axis of which crosses the central longitudinal axes 20, 21 of the large facing walls of the guides 15, 16, communicating slots 22, 23 being provided at each of the waveguide junctions, the slot 22 being parallel to and spaced by a distance x from the axis 20 or 21, and the slot 23 being perpendicu- 1ar to, and with its centre spaced a distance x 2 from the axis 20 or 21, wherein x 1 = 1: 76x 2 . In order to increase the width of the wavelength band transmitted by the coupler metallic plates 24 are positioned near the slots 22 parallel to the large walls of the guide. A construction for use as a directional filter for microwaves comprises a rectangular guide 32, Fig. 4, for receiving microwaves from an aerial (not shown), and coupled by slots 22, 23 to circular guides 29, 29<SP>1</SP>. The latter form cavity resonators tunable by screws 31, 31<SP>1</SP>, respectively, to the mean frequencies of the two wavebands to be separated. Thus one waveband passes through the resonator 29 to a rectangular guide 27 via coupling slots 22, 23, whilst the other waveband passes through the resonator 29<SP>1</SP> to a rectangular guide 27<SP>1</SP> via coupling slots 22<SP>1</SP>, 23<SP>1</SP>. The two wavebands are received at the mouths 30, 30<SP>1</SP> of the rectangular guides 27, 271. One end of each of the guides 27, 27<SP>1</SP> and 32 is terminated by a dissipative load element 28, 28<SP>1</SP>, or 33.