GB1171985A - Wide-Band Coupling Apparatus - Google Patents

Abstract

1,171,985. Combining and distributing signals. THOMSON-CSF. 10 Feb., 1967 [25 Feb., 1966], No. 6597/67. Heading H1W. A circuit for separating (or combining) two signals respectively occupying the bands O to F 1 and F 1 to F M comprises two 3 db. couplers 1, 2 having pass-bands F 1 to F M and connected in the manner shown by filters 3, 4 having passbands O to F 1 . The pass-band of the couplers is defined as the band within which they effect equal division of input power. The input is applied at port 10 and comprises signals in both bands. The band F 1 to F M is equally distributed between output ports 11, 12 and, after reflection by the filters 3, 4, is re-combined at the output port 13. The band O to F 1 is distributed between outputs 11, 12 in a proportion determined by a coupling coefficient k which varies with frequency, one portion being applied to port 21 and the other portion to port 22 of coupler 2. A differential phase-shift of # (at a frequency between O and F 1 ) between the two signal portions is introduced either by a phaseshifter 5 or by a difference in path lengths. It is shown in the Specification that if ¢ < k = P 11 /P # 1, where P is the input power transmitted to port 11, then the greater part of the power in the band O to F 1 is transmitted to the output port 20. The port 23 is terminated by a matched load 6. A triplate version of the circuit (Figs. 3, 4) uses three ground planes 14, 24, 25, the two couplers being arranged one on either side of the common plane 25. The line conductors are supported between the ground planes by insulators 7 and the two halves of the circuit connected by connectors 8. The filters 3, 4 consist of quarter-wave sections of line conductor.