Compensation for parasitic coupling between RF or microwave transistors in the same package
View Patent ↗Parasitic coupling effects between RF or microwave transistors provided in a common package are compensated by connecting one or more capacitors between the transistors. By connecting the capacitor(s) at a location that corresponds to the site of the coupling, the compensation is effective over a wide frequency band. This coupling-compensation makes it feasible to provide, in a common package, RF or microwave transistors intended to operate in quadrature, thereby improving performance matching and operating efficiency of the overall device.
1. A method of compensating parasitic coupling between a pair of RF or microwave transistors provided in a common package, the method comprising the steps of:
determining one or more locations where parasitic coupling is operative between the pair of RF or microwave transistors when said transistors are being used in quadrature; and
connecting a capacitor between the transistors at least one of said one or more locations.
2. The parasitic-coupling compensation method of claim 1 , wherein said RF or microwave transistors are formed on a common semiconductor substrate, at least one capacitor is connected between said pair of RF or microwave transistors, and said at least one capacitor comprises an integrated capacitor provided on said semiconductor substrate.
3. The parasitic-coupling compensation method of claim 1 , wherein:
the parasitic coupling occurs between wire areas of the pair of transistors, and
the connecting step comprises connecting at least one capacitor between a respective wire area of one of said pair of transistors and a wire area of the other of said pair of transistors.
4. The parasitic-coupling compensation method of claim 3 , wherein:
said RF or microwave transistors comprise associated circuit elements,
the parasitic coupling includes a coupling between a first wire area corresponding to a circuit element associated with one of the pair of transistors and a second wire area corresponding to a circuit element associated with the other of the pair of transistors, and
the connecting step comprises connecting a capacitor between said first and second wire areas.
5. The parasitic-coupling compensation method of claim 1 , wherein the connecting step comprises connecting a first capacitor between the inputs of said pair of RF or microwave transistors and connecting a second capacitor between the outputs of said pair of RF or microwave transistors.
6. A packaged electronic device comprising:
a pair of RF or microwave transistors; and
at least one capacitor connected between said pair of transistors;
wherein said at least one capacitor comprises a capacitor connected between the transistors at least one location where parasitic coupling is operative between the two transistors when the two transistors are being used in quadrature.
7. The packaged electronic device of claim 6 , wherein said RF or microwave transistors are formed on a common semiconductor substrate and said at least one capacitor comprises an integrated capacitor provided on said semiconductor substrate.
8. The packaged electronic device of claim 6 , comprising a first capacitor connected between the inputs of said pair of RF or microwave transistors and a second capacitor connected between the outputs of said pair of RF or microwave transistors.
9. An RF amplifier comprising a packaged electronic device according to claim 6 .
10. A microwave amplifier comprising a packaged electronic device according to claim 6 .
11. The parasitic-coupling compensation method of claim 2 , wherein:
the parasitic coupling occurs between wire areas of the pair of transistors, and
the connecting step comprises connecting at least one capacitor between a respective wire area of one of said pair of transistors and a wire area of the other of said pair of transistors.
12. The parasitic-coupling compensation method of claim 2 , wherein the connecting step comprises connecting a first capacitor between the inputs of said pair of RF or microwave transistors and connecting a second capacitor between the outputs of said pair of RF or microwave transistors.
13. The parasitic-coupling compensation method of claim 3 , wherein the connecting step comprises connecting a first capacitor between the inputs of said pair of RF or microwave transistors and connecting a second capacitor between the outputs of said pair of RF or microwave transistors.
14. The parasitic-coupling compensation method of claim 4 , wherein the connecting step comprises connecting a first capacitor between the inputs of said pair of RF or microwave transistors and connecting a second capacitor between the outputs of said pair of RF or microwave transistors.
15. The packaged electronic device of claim 7 , wherein the at least one capacitor further comprises a first capacitor connected between the inputs of said pair of RF or microwave transistors and a second capacitor connected between the outputs of said pair of RF or microwave transistors.
16. An RF amplifier comprising a packaged electronic device according to claim 7 .
17. An RF amplifier comprising a packaged electronic device according to claim 8 .
18. A microwave amplifier comprising a packaged electronic device according to claim 7 .
19. A microwave amplifier comprising a packaged electronic device according to claim 8 .