GB864324A - Coupling arrangement - Google Patents

Abstract

864,324. R.F. couplings. COMPAGNIE FRANCAISE THOMSON-HOUSTON. June 4, 1959 [June 4, 1958], No. 19173/59. Addition to 793,833. Class 40(7) A radio-frequency coupling arrangement for separating signals of two different frequencies received at a common input to two respective outputs comprises two lengths of transmission line or waveguide one of which connects the input to a matched impedance and the other the two outputs. The lengths are joined by two directional couplers spaced apart along them and two similar tuned filters, capable of transmitting signals of one frequency but reflecting those of the other, are placed, one in each length, midway between the couplers. The invention is of particular use in separating signals combined, for example by the coupling arrangement of the parent Specification, and passed through a rotating joint 4 in a common waveguide. The arrangement of the present invention, indicated at 5 and having an associated matched impedance 10 and output lines 8 and 9, separates the two signals and directs that of the frequency accepted by the filters to line 9 and that of the rejected frequency to line 8. To ensure that no signals of the unwanted frequency are passed by either lines 8 or 9 to the respective loads tuned filters 11 and 12 may be placed in these lines. These filters are tuned to accept the respective wanted frequencies and to reject the unwanted frequencies. Any energy reflected by them is not directed back to the input line but absorbed in the load 10. The filters may be waveguide Tee-filters; either of parallel type with the Tee arm connected into the short wall of a rectangular guide or of series type with the Tee arm connected into the broad guide face (Figs. 4a and 4b, both not shown).