Radio frequency front end with tunable filters

Patent metadata

Field	Value
Publication number	US-12003263-B2
Application number	US-202117410902-A
Country	US
Kind code	B2
Filing date	Aug 24, 2021
Priority date	Aug 31, 2020
Publication date	Jun 4, 2024
Grant date	Jun 4, 2024

Abstract

Aspects of this disclosure relate to a radio frequency system with tunable notch filtering. The radio frequency system includes a first tunable filter and a second tunable filter. The first tunable filter is coupled between an output of a power amplifier and a radio frequency switch. The second tunable filter is coupled between an antenna switch and an antenna node. The second tunable filter has a notch at a lower frequency than a notch of the first tunable filter. Related methods and wireless communication devices are also disclosed.

First claim

What is claimed is:

1. A radio frequency system with tunable notch filtering,
the radio frequency system comprising:
a power amplifier having an output;
a multi-throw switch;
a first tunable filter coupled between the output of the power amplifier and the multi-throw switch, the first tunable filter having at least a first tunable notch;
an antenna switch coupled to the multi-throw switch by way of one or more radio frequency signal paths; and
a second tunable filter coupled between the antenna switch and an antenna node, the second tunable filter having at least a second tunable notch, the second tunable notch being at a lower frequency than the first tunable notch, the second tunable filter being an L network that includes a parallel inductor-capacitor circuit and a shunt series inductor-capacitor circuit, and the parallel inductor-capacitor circuit arranged in series between the antenna switch and the antenna node.

2. The radio frequency system of claim 1 wherein the second tunable notch corresponds to a higher order harmonic than the first tunable notch.

3. The radio frequency system of claim 1 wherein the first tunable filter has a plurality of tunable notches, the plurality of tunable notches including the first tunable notch.

4. The radio frequency system of claim 3 wherein the plurality of tunable notches each correspond to a higher respective frequency than the second tunable notch.

5. The radio frequency system of claim 3 wherein the second tunable filter has a single tunable notch, the single tunable notch being the second tunable notch.

6. The radio frequency system of claim 3 wherein the second tunable filter has a second plurality of tunable notches, the second plurality of tunable notches including the second tunable notch.

7. The radio frequency system of claim 1 wherein the parallel inductor-capacitor circuit includes a tunable capacitance circuit.

8. The radio frequency system of claim 7 wherein the shunt series inductor-capacitor circuit includes a second tunable capacitance circuit.

9. The radio frequency system of claim 1 wherein the one or more radio frequency signal paths includes a first radio frequency signal path, and the first radio frequency signal path includes a band pass filter.

10. A radio frequency system with tunable notch filtering, the radio frequency system comprising:
a power amplifier having an output;
a multi-throw switch;
a first tunable filter coupled between the output of the power amplifier and the multi-throw switch, the first tunable filter having at least a first tunable notch;
an antenna switch coupled to the multi-throw switch by way of one or more radio frequency signal paths; and
a second tunable filter coupled between the antenna switch and an antenna node, the second tunable filter having at least a second tunable notch, the second tunable notch being at a lower frequency than the first tunable notch, the second tunable filter including a first inductor, a second inductor mutually coupled to the first inductor, and a tunable capacitance circuit coupled to the first inductor.

11. The radio frequency system of claim 10 wherein the first tunable filter includes a third inductor, a fourth inductor mutually coupled to the third inductor, and a second tunable capacitance circuit coupled to the third inductor.

12. The radio frequency system of claim 10 wherein the second tunable filter is an L network.

13. The radio frequency system of claim 12 wherein the L network includes a parallel inductor-capacitor circuit and a shunt series inductor-capacitor circuit, the parallel inductor-capacitor circuit arranged in series between the antenna switch and the antenna node.

14. The radio frequency system of claim 10 further comprising a tunable shunt capacitance circuit coupled to a node between the first tunable filter and the multi-throw switch, the tunable shunt capacitance circuit being configured to tune a load line.

15. A radio frequency system with tunable notch filtering, the radio frequency system comprising:
a power amplifier having an output;
a multi-throw switch;
a first tunable filter coupled between the output of the power amplifier and the multi-throw switch, the first tunable filter having at least a first tunable notch, the first tunable filter including a first inductor, a second inductor mutually coupled to the first inductor, and a tunable capacitance circuit coupled to the first inductor;
an antenna switch coupled to the multi-throw switch by way of one or more radio frequency signal paths, and
a second tunable filter coupled between the antenna switch and an antenna node, the second tunable filter having at least a second tunable notch, the second tunable notch being at a lower frequency than the first tunable notch.

16. The radio frequency system of claim 15 further comprising a tunable shunt capacitance circuit coupled to a node between the first tunable filter and the multi-throw switch, the tunable shunt capacitance circuit being configured to tune a load line.

17. The radio frequency system of claim 15 wherein the second tunable filter is an L network that includes a parallel inductor-capacitor circuit and a shunt series inductor-capacitor circuit, the parallel inductor-capacitor circuit arranged in series between the antenna switch and the antenna node.

18. A radio frequency system with tunable notch filtering, the radio frequency system comprising:
a power amplifier having an output;
a multi-throw switch;
a first tunable filter coupled between the output of the power amplifier and the multi-throw switch, the first tunable filter having at least a first tunable notch;
a tunable shunt capacitance circuit coupled to a node between the first tunable filter and the multi-throw switch, the tunable shunt capacitance circuit being configured to tune a load line;
an antenna switch coupled to the multi-throw switch by way of one or more radio frequency signal paths; and
a second tunable filter coupled between the antenna switch and an antenna node, the second tunable filter having at least a second tunable notch, the second tunable notch being at a lower frequency than the first tunable notch.

19. The radio frequency system of claim 18 wherein the second tunable filter is an L network that includes a parallel inductor-capacitor circuit and a shunt series inductor-capacitor circuit, the parallel inductor-capacitor circuit arranged in series between the antenna switch and the antenna node.

20. The radio frequency system of claim 18 wherein the second tunable notch corresponds to a higher order harmonic than the first tunable notch.

Assignees

• Skyworks Solutions Inc

Inventors

• Jia Fei
• Ellis Joshua Kawika
• Chen Kun
• Farahvash Shayan
• Ju Haisu
• Cao Haibo

Classifications

• H04B1/1036 Primary

  with automatic suppression of narrow band noise or interference, e.g. by using tuneable notch filters (H04B1/123 takes precedence; filter circuits H03H) · CPC title

• H03F3/245

  with semiconductor devices only · CPC title

• H03H7/0115

  comprising only inductors and capacitors (H03H7/075, H03H7/09, H03H7/12, H03H7/13 take precedence) · CPC title

• H04M1/0202

  Portable telephone sets, e.g. cordless phones, mobile phones or bar type handsets (constructional features of telephone transmitters or receivers, e.g. of speakers or microphones H04M1/03) · CPC title

• H03F2200/171

  A filter circuit coupled to the output of an amplifier · CPC title