Radio frequency switching circuit

• US 20060009164A1
• Filed: 06/15/2005
• Published: 01/12/2006
• Est. Priority Date: 07/07/2004
• Status: Abandoned Application

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Kataoka, Shigeru
• Application Number:
  US11/152,242
• Publication Number:
  US 20060009164A1
• Time in Patent Office: Days
• US Class Current: 455/83
• CPC Class Codes: H04B 1/44 Transmit/receive switching
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver

Abstract

By using the leakage of an RF signal, transmitted power is controlled without using a signal distributor such as a directional coupler. The RF signal is leaked due to a parasitic capacitance between the source (or drain) terminal and the gate terminal of an FET constituting a transmission-side FET switching circuit of an RF switching circuit.

Claims

1. A radio frequency switching circuit, comprising:

an FET switching circuit interposed between a first input fed with a radio frequency output from a radio frequency amplifier and a first output for supplying the radio frequency output to a subsequent stage, the FET switching circuit being turned on/off in response to a switching signal, and

a second output for feeding back, to the radio frequency amplifier, a radio frequency signal having leaked to a control terminal of the FET switching circuit.

2. The radio frequency switching circuit according to claim 1, wherein

the FET switching circuit comprises a through FET switching circuit including an output circuit having one end connected to the first input and the other end connected to the first output, wherein a radio frequency signal having leaked to a control terminal of the through FET switching circuit is fed back to the radio frequency amplifier.

3. The radio frequency switching circuit according to claim 1, wherein

the FET switching circuit comprises a through FET switching circuit including an output circuit having one end connected to the first input and the other end connected to the first output, and a shunt FET switching circuit having an output circuit connected between the first input and a reference voltage, wherein a radio frequency signal having leaked to a control terminal of the through FET switching circuit is fed back to the radio frequency amplifier.

4. The radio frequency switching circuit according to claim 1, wherein

the FET switching circuit comprises a through FET switching circuit of a multistage FET comprising a plurality of FETs having source/drain terminals connected in series, the multistage FET including an output circuit having one end connected to the first input and the other end connected to the first output, wherein a radio frequency signal having leaked to at least one or more control terminals of the FET switching circuit is fed back to the radio frequency amplifier.

5. The radio frequency switching circuit according to claim 2, further comprising a coupling part interposed between the control terminal of the through FET switching circuit and the second output, the coupling part allowing only passage of a radio frequency signal component.

6. The radio frequency switching circuit according to claim 3, further comprising a coupling part interposed between the control terminal of the through FET switching circuit and the second output, the coupling part allowing only passage of a radio frequency signal component.

7. The radio frequency switching circuit according to claim 4, further comprising a coupling part interposed between the control terminal of the through FET switching circuit and the second output, the coupling part allowing only passage of a radio frequency signal component.

10. The radio frequency switching circuit according to claim 2, further comprising a coupling part interposed between a control terminal of a shunt FET switching circuit and the second output, the coupling part allowing only passage of a radio frequency signal component.

11. The radio frequency switching circuit according to claim 3, further comprising a coupling part interposed between a control terminal of a shunt FET switching circuit and the second output, the coupling part allowing only passage of a radio frequency signal component.

12. The radio frequency switching circuit according to claim 4, further comprising a coupling part interposed between a control terminal of a shunt FET switching circuit and the second output, the coupling part allowing only passage of a radio frequency signal component.

13. The radio frequency switching circuit according to claim 5, further comprising a coupling part interposed between a control terminal of a shunt FET switching circuit and the second output, the coupling part allowing only passage of a radio frequency signal component.

8. A radio frequency switching circuit, comprising:

an FET switching circuit interposed between a first input fed with a radio frequency output from a radio frequency amplifier and a first output for supplying the radio frequency output to a subsequent stage, the FET switching circuit being turned on/off in response to a switching signal, and

a second output for feeding back, to the radio frequency amplifier, a radio frequency signal having leaked to a control terminal of the FET switching circuit, wherein

the FET switching circuit comprises a through FET switching circuit including an output circuit having one end connected to the first input and the other end connected to the first output, and a shunt FET switching circuit including an output circuit connected between the first input and a reference voltage, wherein a radio frequency signal having leaked to a control terminal of the shunt FET switching circuit is fed back to the radio frequency amplifier.

14. The radio frequency switching circuit according to claim 8, further comprising a coupling part interposed between the control terminal of the shunt FET switching circuit and the second output, the coupling part allowing only passage of a radio frequency signal component.

9. A radio frequency switching circuit, comprising:

an FET switching circuit interposed between a first input fed with a radio frequency output from a radio frequency amplifier and a first output for supplying the radio frequency output to a subsequent stage, the FET switching circuit being turned on/off in response to a switching signal, and

a second output for feeding back, to the radio frequency amplifier, a radio frequency signal having leaked to a control terminal of the FET switching circuit, wherein

the FET switching circuit comprises a through FET switching circuit including an output circuit having one end connected to the first input and the other end connected to the first output, and a shunt FET switching circuit including an output circuit connected between the first input and a reference voltage, and

the shunt FET switching circuit comprises a multistage FET including a plurality of FETs having source/drain terminals connected in series, wherein a radio frequency signal having leaked to a control terminal of the shunt FET switching circuit is fed back to the radio frequency amplifier.

15. The radio frequency switching circuit according to claim 9, further comprising a coupling part interposed between the control terminal of the shunt FET switching circuit and the second output, the coupling part allowing only passage of a radio frequency signal component.