Broadband High Efficiency Impedance Step-Up 180° Phase Shift Hybrid Circuits

1,178,379. R.F. couplings. COLLINS RADIO CO. 21 June, 1968, No. 29818/68. Heading H4A. A step-up hybrid comprises two magnetic circuits (e.g., ferrite rings) 13A, 13B, Fig. 1, having respective closely bunched bifilar windings 12A, 12B, the two wires of each of which may be twisted together. Signal lines 14A, 14B are connected to the respective start ends of one wire of each of the windings 12A, 12B. As shown, the signal lines are of coaxial type, with characteristic impedances R, and their outer conductors are earthed. The start ends of the other wires of the windings 12A, 12B are also earthed. The finish end 16A of one wire of the winding 12A is cross-connected to the start end of that wire of the winding 12B to which is connected the signal line 14B, and the finish end 16B of one wire of the winding 12B is cross-connected to the start end of that wire of the winding 12A to which is connected the signal line 14A. The finish ends 15A, 15B of the other wires of the windings 12A, 12B are connected together. In this way, a balanced difference port is obtained between the ends 16A, 16B, and a sum port is obtained between the commoned ends 15A, 15B and earth, each port having an effective impedance of 2R. A form of construction is described in which the two magnetic circuits consist of side-byside stacks of ferrite washers 22, Fig. 5. Cooling plates 23 are interspersed between the ferrite washers, and both windings pass through apertures 25 in the said plates. In a second embodiment (Fig. 2, not shown) an additional magnetic circuit (19) with a bifilar winding (18) is provided. The balanced difference port of a hybrid as described above is connected to one end of the winding (18) and an unbalanced load (e.g., a coaxial type line) is connected to the other end of the said winding. In a third embodiment (Fig. 3, not shown), the sum ports of two hybrids are parallelled, so that four signal lines are coupled. The difference port of each hybrid is terminated by a resistor of value equal to the impedance looking therein. In a fourth embodiment (Fig. 6, not shown) in which four signal lines are also coupled by two hybrids as described above, the difference ports are connected to a single unbalanced load by means of three further magnetic circuits with bifilar windings, and the sum ports are connected to two unbalanced loads by means of two further magnetic circuits with bifilar windings.