Radio frequency couplers with high directivity

1. A directional coupler, comprising:

a first port;

a second port;

a third port;

a fourth port;

a first inductor having a first connection to the first port and a second connection to the second port;

a second inductor having a first connection to the third port and a second connection to the fourth port;

a first compensation capacitor connected to the first port and the third port; and

a second compensation capacitor connected to the first port and the fourth port;

wherein the first inductor is inductively coupled to the second inductor by a predefined coupling factor, the third port being isolated from the first port by a predefined first isolation factor, and the fourth port being isolated from the first port by a predefined second isolation factor, and

wherein an inductance of the second inductor is substantially greater than an inductance of the first inductor.

2. The directional coupler of claim 1 , further comprising a third compensation capacitor, wherein a capacitance of the third compensation capacitor is lower than a capacitance of the first compensation capacitor.

3. The directional coupler of claim 2 , further comprising a fourth compensation capacitor, wherein a capacitance of the fourth compensation capacitor is greater than a value of the second compensation capacitor.

4. The directional coupler of claim 1 , further comprising a fifth compensation capacitor and a sixth compensation capacitor.

5. The directional coupler of claim 4 , wherein a capacitance of the fifth compensation capacitor is ten times higher than a capacitance of the sixth compensation capacitor, wherein a capacitance of the sixth compensation capacitor is twice as high as a capacitance of the first compensation capacitor.

6. The directional coupler of claim 1 , wherein a first directivity defined by the predefined coupling factor and the first isolation factor is different from a second directivity defined by the predefined coupling factor and the second isolation factor.

7. The directional coupler of claim 1 , wherein an inductance of the second inductor is at least two times greater than an inductance of the first inductor.

8. A directional coupler, comprising:

a first port;

a second port;

a third port;

a fourth port;

a first inductor having a first connection to the first port and a second connection to the second port;

a second inductor having a first connection to the third port and a second connection to the fourth port;

a first compensation capacitor connected to the first port and the third port;

a second compensation capacitor connected to the first port and the fourth port;

a third compensation capacitor connected to the first port and a first node; and

a fourth compensation capacitor connected to the second port and a second node;

wherein an inductance of the second inductor is substantially greater than an inductance of the first inductor.

9. The directional coupler of claim 8 , wherein a value of the third compensation capacitor is approximately one order of magnitude lower than a value of the first compensation capacitor.

10. The directional coupler of claim 8 , wherein a magnitude of a capacitance of the third compensation capacitor is ten times lower than a magnitude of a capacitance of the fourth compensation capacitor.

11. The directional coupler of claim 8 , wherein a capacitance of the third compensation capacitor is twice higher than a capacitance of the first compensation capacitor.

12. The directional coupler of claim 8 , wherein a capacitance of the fourth compensation capacitor is three times higher than a capacitance of the second compensation capacitor.

13. The directional coupler of claim 8 , wherein a capacitance of the fourth compensation capacitor is four times higher than a capacitance of the second compensation capacitor.

14. The directional coupler of claim 8 , wherein an inductance of the second inductor is at least two times greater than an inductance of the first inductor.

15. The directional coupler of claim 8 , wherein each of the first node and the second node comprise a ground node.

16. A directional coupler, comprising:

a first port;

a second port;

a third port;

a fourth port;

a first inductor having a first connection to the first port and a second connection to the second port;

a second inductor having a first connection to the third port and a second connection to the fourth port;

a first compensation capacitor connected to the first port and the third port;

a second compensation capacitor connected to the first port and the fourth port;

a third compensation capacitor connected to the first port and a first node;

a fourth compensation capacitor connected to the second port and a second node;

a fifth compensation capacitor connected to the first node and the third port; and

a sixth compensation capacitor connected to the second node and the fourth port;

wherein the first inductor is inductively coupled to the second inductor by a predefined coupling factor, the third port being isolated from the first port by a predefined first isolation factor, and the fourth port being isolated from the first port by a predefined second isolation factor, and

wherein an inductance of the second inductor is substantially greater than an inductance of the first inductor.

17. The directional coupler of claim 16 , wherein each of the first node and the second node comprise a ground node.

18. The directional coupler of claim 16 , wherein a capacitance of the sixth compensation capacitor is two times higher than a capacitance of the second compensation capacitor.

19. The directional coupler of claim 16 , wherein a capacitance of the fifth compensation capacitor is three times lower than a capacitance of the third compensation capacitor.

20. The directional coupler of claim 16 , a capacitance of the fourth compensation capacitor is higher than all other capacitances.