Granted Patent B2

US 8,798,561 · App. 13/228,063 · Granted Aug 5, 2014

Abstract

Claims (52)

1. A radio-frequency (RF) circuit for handling a plurality of modulated signals having a carrier wavelength, the RF circuit comprising a first transcoupling element that comprises:

a first branch having a first end and a second end; and

a second branch parallel to the first branch, wherein:

the first branch is configured to operate as an impedance inverter that presents at the first end a first impedance, said first impedance being proportional to an inverse of a second impedance presented to the first branch at the second end; and

the second branch is configured to operate as a signal coupler, wherein electromagnetic coupling between the first and second branches causes the second branch to receive an attenuated copy of a signal from the first branch.

2. The RF circuit of claim 1 , wherein the first branch has a length, between the first and second ends, of about one quarter of the carrier wavelength.

3. The RF circuit of claim 1 , wherein the first impedance is different from the second impedance.

4. The RF circuit of claim 3 , wherein:

the second impedance is a fixed impedance; and

the first branch is configured to operate as an impedance transformer.

5. The RF circuit of claim 1 , further comprising circuitry configured to change the second impedance over time.

6. The RF circuit of claim 5 , wherein said circuitry comprises an amplifier.

7. The RF circuit of claim 1 , wherein:

the second branch has a first end and a second end;

the electromagnetic coupling causes the first end of the second branch to carry an attenuated copy of a signal applied to the first end of the first branch; and

the electromagnetic coupling further causes the second end of the second branch to carry an attenuated copy of a signal applied to the second end of the first branch.

8. The RF circuit of claim 7 , wherein at least one of the first and second ends of the second branch is connected to a terminator.

9. The RF circuit of claim 1 , wherein the first and second branches have different respective impedances.

10. The RF circuit of claim 1 , wherein the second end is connected to at least two different lines external to the first transcoupling element.

11. The RF circuit of claim 10 , wherein a first of said at least two different lines connects the second end to a second transcoupling element.

12. The RF circuit of claim 11 , wherein a second of said at least two different lines connects the second end to a first amplifier.

13. The RF circuit of claim 12 , wherein the first end is connected to a second amplifier.

14. The RF circuit of claim 1 , further comprising a second transcoupling element that comprises:

a respective first branch having a length, between a respective first end and a respective second end, of about one quarter of the carrier wavelength; and

a respective second branch parallel to said respective first branch, wherein:

the first end of said respective first branch is connected to the second end of the first branch of the first transcoupling element;

the second end of said respective first branch is connected to a fixed impedance;

said respective first branch is configured to operate as an impedance transformer; and

said respective second branch is configured to operate as a signal coupler, wherein electromagnetic coupling between said respective first branch and said respective second branch causes said respective second branch to receive an attenuated copy of a signal from said respective first branch.

15. The RF circuit of claim 14 , wherein the first branch of the first transcoupling element and said respective first branch of the second transcoupling element have different respective impedances.

16. The RF circuit of claim 1 , further comprising:

a dielectric substrate; and

a patterned conductive layer adjacent to the dielectric substrate, wherein the patterned conductive layer comprises:

a first strip that implements the first branch;

a second strip along a side of the first strip and electromagnetically coupled to the first strip, said second strip implementing the second branch.

17. The RF circuit of claim 16 , wherein:

the patterned conductive layer further comprises a third strip connected to the first end;

a distal end of the third strip is terminated by a shunt; and

the third strip has a length, between the first end and the shunt, of about one quarter of the carrier wavelength.

18. The RF circuit of claim 16 , wherein the patterned conductive layer further comprises first and second interdigitated combs located between the first and second strips, the first comb being attached to the first strip and the second comb being attached to the second strip.

19. The RF circuit of claim 1 , wherein:

the first transcoupling element is a four-terminal device;

each of the four terminals is configured to carry a different respective modulated signal of the plurality of modulated signals;

the first end of the first branch is directly electrically connected to a first terminal of the four terminals;

the second end of the first branch is directly electrically connected to a second terminal of the four terminals;

a first end of the second branch is directly electrically connected to a third terminal of the four terminals; and

a second end of the second branch is directly electrically connected to a fourth terminal of the four terminals.

20. The RF circuit of claim 19 , wherein:

the first terminal is configured to receive a first modulated signal of the plurality of modulated signals;

the second terminal is configured to receive a second modulated signal of the plurality of modulated signals, said second modulated signal being different from the first modulated signal;

the third terminal is configured to output an attenuated copy of the first modulated signal; and

the fourth terminal is configured to output an attenuated copy of the second modulated signal.

Assignments (11)