Adaptive load for coupler in broadband multimode multiband front end module

Patent metadata

Field	Value
Publication number	US-9755670-B2
Application number	US-201615358233-A
Country	US
Kind code	B2
Filing date	Nov 22, 2016
Priority date	May 29, 2014
Publication date	Sep 5, 2017
Grant date	Sep 5, 2017

Abstract

Directional couplers for front end modules (FEMs) are disclosed that include a first port configured to receive a radio-frequency (RF) signal, a second port connected to the first port via a first transmission line and configured to provide an RF output signal, a third port connected to a second transmission line, the second transmission line being electromagnetically coupled to the first transmission line, and a fourth port connected to the second transmission line. The directional couplers further include an adaptive complex termination circuit connected to the fourth port and configured to provide an adaptive complex termination impedance selected to optimize combined performance of the directional couplers over multiple frequency bands.

First claim

What is claimed is:

1. A daisy-chain directional coupler system comprising:
a first directional coupler including a first input port configured to receive a first radio-frequency (RF) signal within a first frequency band, a first output port, a first coupled port, and a first isolated port;
a second directional coupler including a second input port configured to receive a second RF signal within a second frequency band different from the first frequency band, a second output port, a second coupled port connected to the first isolated port, and a second isolated port; and
a termination circuit connected to the second isolated port and configured to provide a shared termination impedance for the first and second directional couplers selected to optimize combined performance of the first and second directional couplers over the first and second frequency bands, the termination circuit including a first inductor, a first capacitor, and a resistor connected in parallel to form a parallel RLC circuit, and the termination circuit further including a second inductor and a second capacitor, the parallel RLC circuit being connected in series with and between the second inductor and the second capacitor, the shared termination impedance being a complex impedance.

2. A radio-frequency (RF) system comprising:
a first directional coupler having a first input port, a first output port, a first coupled port, and a first isolated poet, the first directional coupler configured to receive a first RF signal within a first frequency band at the first input port and to provide the first RF signal on the first output port;
a second directional coupler having a second input port, a second output port, a second coupled port, and a second isolated port, the second directional coupler configured to receive a second RF signal at the second input port and to provide the second RF signal at the second output port, the second RF signal being within a second frequency band different from the first frequency band, the second coupled port being connected to the first isolated port;
a power amplifier module connected to the first input port of the first directional coupler and to the second input port of the second directional coupler and configured to provide the first and second RF signals;
power detection circuitry connected to the first coupled port of the first directional coupler; and
a termination circuit connected to the second isolated port of the second directional coupler and configured to provide a shared termination impedance for the first and second directional couplers selected to optimize combined performance of the first and second directional couplers over the first and second frequency bands, the termination circuit including a first inductor, a first capacitor, and a resistor connected in parallel to form a parallel RLC circuit, and the termination circuit further including a second inductor and a second capacitor, the parallel RLC circuit being connected in series with and between the second inductor and the second capacitor, the shared termination impedance being a complex impedance.

3. A wireless device comprising:
a transceiver configured to process a plurality of RF signals in a corresponding plurality of frequency bands;
an antenna in communication with the transceiver configured to transmit the plurality of RF signals;
a plurality of directional couplers each having an input port configured to receive one of the RF signals in a respective one of the plurality of frequency bands and an output port configured to provide the one of the RF signals to the antenna, the plurality of directional couplers each further including a main transmission line extending between the input port and the output port and a coupled transmission line, the coupled transmission lines of the plurality of directional couplers being connected together in series to provide a daisy-chain of the plurality of directional couplers;
a power amplifier module connected to the input port of each directional coupler in the daisy-chain and configured to provide the plurality of RF signals;
power detection circuitry connected to a coupled port of a first directional coupler in the daisy-chain; and
a termination circuit connected to an isolated port of a last directional coupler in the daisy-chain and configured to provide a shared termination impedance for the plurality of directional couplers that is selected to optimize combined performance of the plurality of directional couplers over the plurality of frequency bands, the termination circuit including a first inductor, a first capacitor, and a resistor connected in parallel to form a parallel RLC circuit, and the termination circuit further including a second inductor and a second capacitor, the parallel RLC circuit being connected in series with and between the second inductor and the second capacitor.

4. The directional coupler of claim 1 wherein a coupler error in at least one of the first frequency band and the second frequency band is 0.3 dB or less.

5. The directional coupler of claim 1 wherein a coupler error in each of the first frequency band and the second frequency band is 0.3 dB or less.

6. The directional coupler of claim 1 wherein the first frequency band includes a frequency of 800 MHz.

7. The directional coupler of claim 1 wherein the first frequency band includes a frequency of 1.98 GHz.

8. The directional coupler of claim 1 further comprising a third directional coupler including a third input port configured to receive a third RF signal within a third frequency band different from the first and second frequency bands, a third output port, a third coupled port, and a third isolated port connected to the first coupled port.

9. The radio-frequency system of claim 2 wherein a coupler error in at least one of the first frequency band and the second frequency band is 0.3 dB or less.

10. The radio-frequency system of claim 2 wherein a coupler error in each of the first frequency band and the second frequency band is 0.3 dB or less.

11. The radio-frequency system of claim 2 wherein the first frequency band includes a frequency of 800 MHz.

12. The radio-frequency system of claim 2 wherein the first frequency band includes a frequency of 1.98 GHz.

13. The radio-frequency system of claim 2 further comprising an antenna switch module coupled to the first output port and the second output port and configured to provide an antenna output port.

14. The wireless device of claim 3 wherein a coupler error in at least one of the plurality of frequency bands is 0.3 dB or less.

15. The wireless device of claim 3 wherein a coupler error in each of the plurality frequency bands is 0.3 dB or less.

16. The wireless device of claim 3 wherein at least one of the plurality of frequency bands includes a frequency of 800 MHz.

17. The wireless device of claim 3 wherein at least one of the plurality of frequency bands includes a frequency of 1.98 GHz.

18. The wireless device of claim 3 further comprising an antenna switch having a plurality of inputs each coupled to the output port of a corresponding one of the plurality of directional couplers and a switch output coupled to the antenna.

19. The wireless device of claim 3 further comprising at least one of a memory, a baseband sub-system, a user interface, and a battery.

Assignees

• Skyworks Solutions Inc

Inventors

• Chen David Ruimin
• Chang Shiaw Wen
• Enobakhare Ede Peter
• Duverneay Brian Blu

Classifications

• H03H7/38

  Impedance-matching networks · CPC title

• H04W88/06

  adapted for operation in multiple networks {or having at least two operational modes}, e.g. multi-mode terminals · CPC title

• H04L25/0278 Primary

  Arrangements for impedance matching · CPC title

• H04B1/04 Primary

  Circuits · CPC title

• H01P1/213

  combining or separating two or more different frequencies (H01P1/215 takes precedence) · CPC title