Resistorless radio frequency hybrid signal splitter

Claim 2

A hybrid radio frequency signal splitter for impedance matching of coaxial RF input line to a pair of coaxial RF output lines over a wide preselected frequency band, comprising a radio frequency cylindrical ferrite core having a substantially stable resistivity over the preselected frequency band, said core having an axial bore formed therein and having a preselected axial dimension, such that said core is effective to define an equivalent radio frequency resistance bearing a predetermined ratio to the characteristic impedance of the RF input and output lines, a radio frequency coil wound about the core for inductive coupling therewith, said coil having a pair of end terminals and an intermediate terminal effectively electrically located between the end terminals, said equivalent resistance being effectively defined across said end terminals, said end terminals and intermediate terminal being arranged for coupling to the RF input and RF output lines to provide impedance matching therebetween with substantial RF isolation between said RF output lines, and a step-down transformer having a pair of end terminals and an intermediate terminal, said intermediate terminal being coupled to the intermediate terminal of said coil, the RF lines each having like characteristic impedances, the end terminals of said coil being arranged for coupling to individual RF output lines and the end terminals of said stepdown transformer being arranged for coupling to the coaxial input RF line, said radio frequency resistance of said core being selected to be commensurate with about twice the characteristic impedance of the RF output lines.

Claim 3

A hybrid radio frequency signal splitter for impedance matching of an RF balanced twin-lead input line to several like RF balanced output lines over a wide preselected radio frequency band with isolation between RF output lines, comprising a ferrite core having a substantially stable resistivity over the preselected frequency band with said core sized to produce a radio frequency resistance bearing a predetermined ratio to the characteristic impedances of the balance input and output lines, a first autotransformer winding having a pair of end terminals and an intermediate terminal with the first winding inductively coupled to the core and with the core RF resistance effectively coupled across the end terminals, a second autotransformer winding having a pair of end terminals and an intermediate terminal with the second winding inductively coupled to the core and with the RF resistance of the core effectively coupled across the end terminals, an impedance transformer having a pair of end terminals arranged for coupling to a first balanced twin-lead RF line and further having a pair of intermediate terminals coupled respectively to the intermediate terminals of the first and second windings, with one of each end terminal of the first and second windings arranged for coupling to a first twin-lead balanced output line, and with the other end terminals of the first and second windings arranged for coupling to a second twin-lead balanced output line.

Claim 4

A hybrid radio frequency signal splitter for impedance matching of an RF balanced twin-lead input line to several like RF balanced output lines over a wide preselected radio frequency band with isolation between RF output lines, comprising a ferrite core having a substantially stable resistivity over the preselected frequency band with said core sized to produce a radio frequency resistance bearing a predetermined ratio to the characteristic impedances of the balance input and output lines, a first autotransformer winding having a pair of end terminals and an intermediate terminal with the first winding inductively coupled to the core and with the core RF resistance effectively coupled across the end terminals, a second autotransformer winding having a pair of end terminals and an intermediate terminal with the second winding inductively coupled to the core and with the RF resistance of the core effectively coupled across the end terminals, an impedance transformer having a pair of end terminals arranged for coupling to a first balanced twin-lead RF line and further having a pair of intermediate terminals coupled respectively to the intermediate terminals of the first and second windings, with one of each end terminal of the first and second windings arranged for coupling to a first twin-lead balanced output line, and with the other end terminals of the first and second windings arranged for coupling to a second twin-lead balanced output line.

Claim 5

The device as recited in claim 2 wherein the RF ferrite core is a cylinder with a central bore between the cylinder ends and wherein said first and second windings are wound with a preselected number of substantially axially parallel turns about the core with the end terminals of each winding protruding from opposite ends of the core and with the intermediate Terminals formed at radially outer parts of windings at selected axial core locations and with the axial length of the core selected to provide said predetermined RF resistance effectively across the end terminals of the windings.

Claim 6

The device as recited in claim 2 wherein said RF resistance has a value about equal to that of the characteristic impedances of the balanced RF twin-lead lines.

Claim 7

The device as recited in claim 2 wherein said RF resistance has a value about equal to that of the characteristic impedance of the balanced RF twin-lead output lines being coupled to the end terminals of the windings and about twice the characteristic impedance of the balanced RF input line coupled to the intermediate taps of the impedance transformer.

Claim 8

The device as recited in claim 5 wherein said impedance transformer provides across its intermediate terminals a characteristic impedance of about one-half of the characteristic impedance of a balanced line coupled to its end terminals.

Claim 9

A hybrid radio frequency signal splitter for impedance matching of an RF coaxial input line to four coaxial RF output lines over a wide preselected frequency band, comprising three radio frequency coils, each wound inductively about selected ones of a plurality of radio frequency ferrite cores each of said cores having a substantially stable resistivity over the preselected frequency band with said core being sized to produce a radio frequency resistance bearing a predetermined ratio to the characteristic impedances of the coaxial RF input and output lines, each of said coils having a pair of end terminals and an intermediate terminal effectively electrically located between the end terminals with individual end terminals of two coils respectively coupled to said four coaxial RF output lines, a pair of impedance step-down autotransformers, each having a pair of end terminals and an intermediate terminals, the intermediate terminal of each transformer being respectively coupled to the intermediate terminals of two of said coils, each end terminal of the step-down transformers being respectively coupled to the end terminals of the third coil, said third coil being arranged to have its intermediate terminal coupled to the coaxial RF input line, said step-down transformers providing about a two-to-one impedance change from end terminal connected inputs to intermediate terminal connected outputs, and said RF resistance of the core inductively coupled to the third coil being selected to about four times the characteristic impedance of the RF input line and with the RF resistance of said core inductively coupled to the first and second coils being selected to provide an RF resistance of about twice the characteristic impedance of each of the coaxial RF output lines.

Claim 10

A hybrid radio frequency signal splitter for impedance matching of an RF coaxial input line to four coaxial RF output lines over a wide preselected frequency band, comprising three radio frequency coils, each wound inductively about selected ones of a plurality of radio frequency ferrite cores each of said cores having a substantially stable resistivity over the preselected frequency band with said core being sized to produce a radio frequency resistance bearing a predetermined ratio to the characteristic impedances of the coaxial RF input and output lines, each of said coils having a pair of end terminals and an intermediate terminal effectively electrically located between the end terminals with individual end terminals of two coils respectively coupled to said four coaxial RF output lines, a pair of impedance step-down autotransformers, each having a pair of end terminals and an intermediate terminals, the intermediate terminal of each transformer being respectively coupled to the intermediate terminals of two of said coils, each end terminal of the step-down transformers being respectively coupled to the end terminals of the third coil, said third coil being arranged to have its intermediate terminal coupled to the coaxial RF input line, said step-down transformers providing about a two-to-one impedance change from end terminal connected inputs to intermediate terminal connected outputs, and said RF resistance of the core inductively coupled to the third coil being selected to about four times the characteristic impedance of the RF input line and with the RF resistance of said core inductively coupled to the first and second coils being selected to provide an RF resistance of about twice the characteristic impedance of each of the coaxial RF output lines.

Claim 11

A hybrid radio frequency signal splitter for impedance matching of a coaxial RF input line to a pair of coaxial RF output lines over a wide preselected frequency band, comprising a radio frequency cylindrical ferrite core having a substantially stable resistivity over the preselected frequency band, said core having an axial bore formed therein and having a preselected axial dimension, such that said core is effective to define an equivalent radio frequency resistance bearing a predetermined ratio to the characteristic impedance of the RF input and output lines, a radio frequency coil wound about the core for inductive coupling therewith, said coil having a pair of end terminals and an intermediate terminal effectively electrically located between the end terminals, said equivalent resistance being effectively defined across said end terminals, said end terminals and intermediate terminal being arranged for coupling to the RF input and RF output lines to provide impedance matching therebetween with substantial RF isolation between said RF output lines, a pair of impedance step-down transformers each having a pair of end terminals and an inteRmediate terminal, said intermediate terminals of said step-down transformers being coupled to the coaxial output RF lines and an end terminal of each of said step-down transformers being coupled to the end terminals of said coil inductively wound to said core, the intermediate terminal of said coil being coupled to the coaxial RF input line, said radio frequency core resistance being selected to exceed the characteristic impedances of the RF input and output lines by a factor of about four.

Claim 12

A hybrid radio frequency signal splitter for impedance matching of a coaxial RF input line to a pair of coaxial RF output lines over a wide preselected frequency band, comprising a radio frequency cylindrical ferrite core having a substantially stable resistivity over the preselected frequency band, said core having an axial bore formed therein and having a preselected axial dimension, such that said core is effective to define an equivalent radio frequency resistance bearing a predetermined ratio to the characteristic impedance of the RF input and output lines, a radio frequency coil wound about the core for inductive coupling therewith, said coil having a pair of end terminals and an intermediate terminal effectively electrically located between the end terminals, said equivalent resistance being effectively defined across said end terminals, said end terminals and intermediate terminal being arranged for coupling to the RF input and RF output lines to provide impedance matching therebetween with substantial RF isolation between said RF output lines, a pair of impedance step-down transformers each having a pair of end terminals and an inteRmediate terminal, said intermediate terminals of said step-down transformers being coupled to the coaxial output RF lines and an end terminal of each of said step-down transformers being coupled to the end terminals of said coil inductively wound to said core, the intermediate terminal of said coil being coupled to the coaxial RF input line, said radio frequency core resistance being selected to exceed the characteristic impedances of the RF input and output lines by a factor of about four.