Rat-race balun and associated method for reducing the footprint of a rat-race balun
AssigneeThales
InventorsAymeric Cailleux, Laure Hogommat-Chabrot
Life of this patent
Estimating the term…
Abstract
A rat-race balun includes a transmission line loop and 4 input-output ports P1, P2, P3, P4 connected to the transmission line loop, the respective transmission line section between the adjacent ports P1 and P4 is of electrical length 2θ2, of impedance Z3 and is a line section loaded by a capacitor of capacitance C2; where θ2<135 and the following equalities are satisfied: C 2 = - 2 tan ( θ 2 ) ω Z P 1 P 4 tan ( 2 θ 2 ) and Z 3 = - Z P 1 P 4 tan ( θ 2 ) w being equal to 2πf, with f the operating frequency, and ZP1P4 being the impedance of the unloaded transmission line section of physical length 3λ/4 equivalent to the loaded line section.
Claims9
A rat-race balun, comprising a transmission line loop and 4 input-output ports P1, P2, P3, P4 connected to said transmission line loop, said balun being designed to receive a first signal on the port P1, and to divide said first signal into a second signal that is delivered to the port P2 and a third signal that is delivered to the port P4, said second signal and said third signal being in phase opposition with one another, wherein the ports adjacent to one another from among the ports P1, P2, P3, P4 are connected by respective sections of the transmission line loop, and at least some of said sections are capacitor-loaded transmission line sections;
- said balun being wherein:
- the respective transmission line section between the adjacent ports P1 and P4 is of electrical length 2θ2, of impedance Z3 and is a line section loaded by a capacitor of capacitance C2;
- where θ2<135 and the following equalities are satisfied:
- C
-
- 2
- =
- -
- 2
-
- tan
-
- (
- θ
- 2
- )
- ω
-
- Z
- P
-
- 1
-
- P
-
- 4
-
- tan
-
- (
- 2
-
- θ
- 2
- )
- and
-
- Z
- 3
- =
- -
- Z
- P
-
- 1
-
- P
-
- 4
- tan
-
- (
- θ
- 2
- )
- w being equal to 2πf, with f the operating frequency, and
- ZP1P4 being the impedance of the unloaded transmission line section of physical length 3λ/4 equivalent to said loaded line section.
A method for reducing the footprint of a rat-race balun comprising a transmission line loop and 4 input-output ports P1, P2, P3, P4 connected to said transmission line loop, said balun being designed to receive a first signal on the port P1, and to divide said first signal into a second signal that is delivered to the port P2 and a third signal that is delivered to the port P4, said second signal and said third signal being in phase opposition with one another, wherein the ports adjacent to one another from among the ports P1, P2, P3, P4 are connected by respective sections of the transmission line loop, and at least some of said sections are capacitor-loaded transmission line sections, said method comprising the following step implemented by an electronic device for determining rat-race balun characteristics:
- the respective transmission line section between the adjacent ports P1 and P4 being of electrical length 2θ2, of impedance Z3 and being a line section loaded by a capacitor of capacitance C2, determining the impedance Z3 and the capacitance C2, satisfying θ2<135 and the following equalities:
- C
-
- 2
- =
- -
- 2
-
- tan
-
- (
- θ
- 2
- )
- ω
-
- Z
- P
-
- 1
-
- P
-
- 4
-
- tan
-
- (
- 2
-
- θ
- 2
- )
- and
-
- Z
- 3
- =
- -
- Z
- P
-
- 1
-
- P
-
- 4
- tan
-
- (
- θ
- 2
- )
- w being equal to 2πf, with f the operating frequency, and
- ZP1P4 being the impedance of the unloaded transmission line section of physical length 3λ/4 equivalent to said loaded line section.
Dependencies are inferred from the claim text.