System and method for a radio frequency coupler
In accordance with an embodiment, a directional coupler includes a coupler circuit and at least one amplifier coupled between a coupler circuit isolated port and a directional coupler isolated port and/or between a coupler circuit coupled port and a directional coupler coupled port. In various embodiments, the directional coupler is disposed over and/or in a substrate.
1. A directional coupler comprising:
a coupler circuit disposed on a monolithic integrated circuit (IC); and
at least one amplifier disposed on the monolithic IC, the at least one amplifier coupled between a coupler circuit isolated port and a directional coupler isolated port and/or between a coupler circuit coupled port and a directional coupler coupled port, wherein the directional coupler isolated port and the directional coupler coupled port each comprise an externally accessible terminal of the monolithic IC, and a directivity of the directional coupler is independent of an external termination coupled to the directional coupler isolated port or the directional coupler coupled port.
2. The directional coupler of claim 1 , wherein the at least one amplifier includes a first amplifier coupled between the coupler circuit coupled port and the directional coupler coupled port.
3. The directional coupler of claim 2 , further comprising a power detector coupled between the coupler circuit isolated port and a directional coupler isolated port.
4. The directional coupler of claim 1 , wherein the at least one amplifier includes a second amplifier coupled between the coupler circuit isolated port and the directional coupler isolated port.
5. The directional coupler of claim 1 , wherein the at least one amplifier includes a first amplifier coupled between the coupler circuit isolated port and the directional coupler isolated port and a second amplifier coupled between the coupler circuit coupled port and the directional coupler coupled port.
6. The directional coupler of claim 1 , wherein the at least one amplifier is an adjustable gain amplifier.
7. The directional coupler of claim 1 , further comprising at least one internal termination impedance coupled to the coupler circuit coupling port and/or coupler circuit isolated port.
8. The directional coupler of claim 7 , wherein the at least one internal termination impedance is an adjustable impedance.
9. The directional coupler of claim 1 , wherein the at least one amplifier is coupled to the coupler circuit isolated port and/or coupler circuit coupled port through an impedance matching network.
10. The directional coupler of claim 9 wherein the impedance matching network is an adjustable impedance matching network.
11. The directional coupler of claim 1 , wherein the at least one amplifier is coupled to the coupler circuit isolated port and/or coupler circuit coupled port through an attenuator.
12. The directional coupler of claim 11 wherein the attenuator is an adjustable attenuator.
13. The directional coupler of claim 1 , wherein the at least one amplifier is a common source amplifier.
14. The directional coupler of claim 1 , wherein the coupler circuit comprises:
a magnetic transformer comprising a first winding coupled between a coupler circuit input port and a coupler circuit transmit port, and a second winding coupled between a first reference node and the coupler circuit coupled port; and
a phase shift network coupled between either the coupler circuit input port or the coupler circuit transmit port and the coupler circuit isolated port.
15. A directional coupler including a directional coupler input port, a directional coupler transmit port and a directional coupler output port, the directional coupler comprising:
a coupler circuit including a first coupler circuit input port, a first coupler circuit transmit port, a first coupler circuit isolated port and a first coupler circuit coupled port;
an amplifier coupled to the directional coupler output port; and
a switch selectively coupling an input of the amplifier to the coupler circuit coupled port and coupler circuit isolated port, wherein the coupler circuit, amplifier and switch are disposed on a monolithic integrated circuit and an output of the amplifier is coupled to an externally accessible terminal of the monolithic integrated circuit, and a directivity of the directional coupler is independent of an external termination coupled to the directional coupler output port.
16. The directional coupler of claim 15 , wherein the switch couples the amplifier to the coupler circuit coupled port.
17. The directional coupler of claim 15 , wherein the switch couples the amplifier to the first coupler isolated port.
18. The directional coupler of claim 15 , wherein monolithic integrated circuit comprises a semiconductor substrate.
19. A method of operating a monolithic integrated circuit comprising a directional coupler including a coupler circuit, and at least one amplifier coupled between a coupler circuit isolated port and an externally accessible directional coupler isolated port and/or between a coupler circuit coupled port and an externally accessible directional coupler coupled port, the method comprising:
receiving an incident signal at an externally accessible directional coupler input port coupled to a coupler circuit input port;
transmitting the incident signal at an externally accessible directional coupler transmit port coupled to a coupler circuit transmit port; and
monitoring at least one signal at the externally accessible directional coupler coupled port and/or the externally accessible directional coupler isolated port, wherein a directivity of the directional coupler is independent of an external termination coupled to the externally accessible directional coupler isolated port or the externally accessible directional coupler coupled port.
20. The method of claim 19 , wherein the monitoring the at least one signal includes monitoring a first signal at the externally accessible directional coupler coupled port.
21. The method of claim 20 , further comprising measuring a reflection comprising monitoring an output of a power detector of the monolithic integrated circuit having an input coupled to the coupler circuit isolated port.
22. The method of claim 19 , wherein the monitoring the at least one signal includes monitoring a second signal at the externally accessible directional coupler isolated port.
23. The method of claim 19 , wherein the monitoring the at least one signal includes monitoring a first signal at the externally accessible directional coupler coupled port and a second signal at the externally accessible directional coupler isolated port.
24. The method of claim 19 , wherein the at least one amplifier includes a first amplifier, the method further comprising selectively coupling an input of the first amplifier to one of the coupler circuit coupled port and coupler circuit isolated port.