HIGH-FREQUENCY CIRCUIT, HIGH-FREQUENCY DEVICE AND COMMUNICATIONS APPARATUS

• US 20090207764A1
• Filed: 05/08/2007
• Published: 08/20/2009
• Est. Priority Date: 05/08/2006
• Status: Active Grant

• Current Assignee: Hitachi Metals (Thailand) Ltd.
• Original Assignee: Hitachi Metals (Thailand) Ltd.
• Inventors: Fukamachi, Keisuke, Hagiwara, Kazuhiro, Kemmochi, Shigeru
• Granted Patent: US 8,036,148 B2
• Time in Patent Office: Days
• US Class Current: 370/297
• CPC Class Codes: H01L 2223/6677 for antenna, e.g. antenna included within housing of semiconductor device
• CPC Class Codes: H01L 2223/6688 Mixed frequency adaptations, i.e. for operation at different frequencies
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2924/15313 being a land array, e.g. LGA
• CPC Class Codes: H01L 2924/19105 in a side-by-side arrangement on a common die mounting substrate
• CPC Class Codes: H04B 1/0057 using diplexing or multiplexing filters for selecting the desired band
• CPC Class Codes: H04B 1/44 Transmit/receive switching

Abstract

A high-frequency circuit for wireless communications selectively using a first frequency band and a second frequency band lower than the first frequency band, comprising an antenna terminal; first and second transmission terminals to which transmitting signals in the first and second frequency bands are input; first and second receiving terminals from which received signals in the first and second frequency bands are output; a diplexer circuit for branching a first-frequency-band-signal path and a second-frequency-band-signal path; a switch circuit for switching a path for a transmitting signal and a path for a received signal; a low-noise amplifier circuit disposed between the switch circuit and the second receiving terminal for amplifying a received signal in the second frequency band; and first and second filter circuits disposed between the antenna terminal and the low-noise amplifier circuit in this order from the antenna terminal, both filter circuits passing a received signal in the second frequency band but blocking a frequency band lower than the second frequency band, and the band blocked by the first filter circuit being lower than the band blocked by the second filter circuit.

Claims

1. A high-frequency circuit for wireless communications selectively using at least a first frequency band and a second frequency band lower than said first frequency band, comprising

an antenna terminal;

a first transmission terminal to which a transmitting signal in said first frequency band is input;

a second transmission terminal to which a transmitting signal in said second frequency band is input;

a first receiving terminal from which a received signal in said first frequency band is output;

a second receiving terminal from which a received signal in said second frequency band is output;

a switch circuit for switching the connection of said antenna terminal to said first and second transmission terminals and the connection of said antenna terminal to said first and second receiving terminals;

a first diplexer circuit disposed between said switch circuit and said first and second transmission terminals;

a second diplexer circuit disposed between said switch circuit and said first and second receiving terminals;

a first power amplifier circuit disposed between said first diplexer circuit and said first transmission terminal;

a second power amplifier circuit disposed between said first diplexer circuit and said second transmission terminal;

a low-noise amplifier circuit disposed between said switch circuit and said second receiving terminal for amplifying at least a received signal in said second frequency band;

a first highpass filter disposed between said antenna terminal and said switch circuit; and

a second highpass filter circuit disposed between said switch circuit and said low-noise amplifier circuit,

both highpass filter circuits passing a received signal in said second frequency band but blocking a frequency band lower than said second frequency band, and a band blocked by said first highpass filter circuit being lower than a band blocked by said second highpass filter circuit.

2. The high-frequency circuit according to claim 1, wherein said low-noise amplifier circuit is disposed between said switch circuit and said second diplexer circuit.

3. The high-frequency circuit according to claim 2, comprising a bypass parallel-connected to said low-noise amplifier circuit.

4. The high-frequency circuit according to claim 3, wherein said second filter circuit is disposed between a branching point of said bypass and said low-noise amplifier circuit, and said low-noise amplifier circuit.

5. The high-frequency circuit according to claim 1, comprising a voltage-applying terminal for applying constant voltage to said first and second power amplifier circuits, and a control circuit receiving voltage from said voltage-applying terminal and outputting a control bias voltage to said first and second power amplifier circuits and said low-noise amplifier circuit.

6. The high-frequency circuit according to claim 5, wherein said control circuit comprising a voltage-inputting terminal, a terminal for outputting bias voltage for said first power amplifier circuit, a terminal for outputting bias voltage for said second power amplifier circuit, a terminal for outputting bias voltage for said low-noise amplifier circuit, a first switch for turning on or off bias voltage for said first power amplifier circuit, a second switch for turning on or off bias voltage for said second power amplifier circuit, a third switch for turning on or off bias voltage for said low-noise amplifier circuit, a fourth switch disposed between a common terminal of said first and second switches and said voltage-inputting terminal, a resistor parallel-connected to said fourth switch, and first to fourth signal-inputting terminals for the ON/OFF control of said first to fourth switches.

7. The high-frequency circuit according to claim 1, wherein another low-noise amplifier circuit for amplifying a received signal in said first frequency band is disposed between said switch circuit and said first receiving terminal, and said second diplexer circuit is disposed between (a) said low-noise amplifier circuit and said other low-noise amplifier circuit, and (b) said switch circuit.

17. A high-frequency device having the high-frequency circuit recited in claim 1, comprising an integral laminate comprising pluralities of dielectric ceramic layers provided with pattern electrodes, and devices mounted on said laminate, said first and second diplexer circuits being formed by said pattern electrodes in said laminate, and semiconductor devices for said switch circuit, said first and second power amplifier circuits and said low-noise amplifier circuit being mounted on said laminate.

18. A communications apparatus comprising the high-frequency device recited in claim 17.

8. A high-frequency circuit for wireless communications selectively using at least a first frequency band and a second frequency band lower than said first frequency band, comprising

an antenna terminal;

a first transmission terminal to which a transmitting signal in said first frequency band is input;

a second transmission terminal to which a transmitting signal in said second frequency band is input;

a first receiving terminal from which a received signal in said first frequency band is output;

a second receiving terminal from which a received signal in said second frequency band is output;

a first diplexer circuit disposed between said switch circuit and said first and second transmission terminals;

a second diplexer circuit disposed between said switch circuit and said first and second receiving terminals;

a first power amplifier circuit disposed between said first diplexer circuit and said first transmission terminal;

a second power amplifier circuit disposed between said first diplexer circuit and said second transmission terminal;

a first low-noise amplifier circuit disposed between said second diplexer circuit and said first receiving terminal;

a second low-noise amplifier circuit disposed between said second diplexer circuit and said second receiving terminal for amplifying a received signal in said second frequency band;

a highpass filter circuit disposed between said antenna terminal and said switch circuit; and

a bandpass filter circuit disposed between said second diplexer circuit and said second low-noise amplifier circuit,

both filter circuits passing a received signal in said second frequency band but blocking at least a frequency band lower than said second frequency band, and a band blocked by said highpass filter circuit being lower than a band blocked by said bandpass filter circuit.

both filter circuits passing a received signal in said second frequency band but blocking at least a frequency band lower than said second frequency band, and a band blocked by said highpass filter circuit being lower than a band blocked by said bandpass filter circuit.

9. The high-frequency circuit according to claim 8, comprising a bandpass filter circuit between said first low-noise amplifier circuit and said first receiving terminal.

10. The high-frequency circuit according to claim 8, comprising bandpass filter circuits each between said first power amplifier circuit and said first transmission terminal, and between said second power amplifier circuit and said second transmission terminal.

11. The high-frequency circuit according to claim 8, comprising a voltage-applying terminal for applying constant voltage to said first and second power amplifier circuits, and a control circuit receiving voltage from said voltage-applying terminal and outputting a control bias voltage to said first and second power amplifier circuits.

12. The high-frequency circuit according to claim 11, wherein said control circuit outputs a control bias voltage for said first and second low-noise amplifier circuits.

13. A high-frequency circuit for wireless communications selectively using at least a first frequency band and a second frequency band lower than said first frequency band, comprising

an antenna terminal;

a first transmission terminal to which a transmitting signal in said first frequency band is input;

a second transmission terminal to which a transmitting signal in said second frequency band is input;

a first receiving terminal from which a received signal in said first frequency band is output;

a second receiving terminal from which a received signal in said second frequency band is output;

a diplexer circuit for branching a signal input from said antenna terminal to a circuit for said first frequency band and a circuit for said second frequency band, and transmitting signals from circuits for said first and second frequency bands to said antenna terminal;

a first switch circuit disposed on the first frequency band circuit side of said diplexer circuit for switching a transmission path and a receiving path;

a first power amplifier circuit disposed between said first switch circuit and said first transmission terminal;

a first low-noise amplifier circuit disposed between said first switch circuit and said first receiving terminal;

a second switch circuit disposed on the second frequency band circuit side of said diplexer circuit for switching a transmission path and a receiving path;

a second power amplifier circuit disposed between said second switch circuit and said second transmission terminal;

a second low-noise amplifier circuit disposed between said second switch circuit and said second receiving terminal for amplifying a received signal in said second frequency band;

a highpass filter circuit disposed between said antenna terminal and said diplexer circuit; and

a bandpass filter circuit disposed between said diplexer circuit and said the second switch circuit,

both filter circuits passing a received signal in said second frequency band but blocking at least a frequency band lower than said second frequency band, and a band blocked by said highpass filter circuit being lower than a band blocked by said bandpass filter circuit.

14. The high-frequency circuit according to claim 13, comprising bandpass filter circuits each between said first power amplifier circuit and said first transmission terminal, and between said first low-noise amplifier circuit and said first receiving terminal.

15. The high-frequency circuit according to claim 14, comprising a voltage-applying terminal for applying constant voltage to said first and second power amplifier circuits, and a control circuit receiving voltage from said voltage-applying terminal and outputting a control bias voltage to said first and second power amplifier circuits.

16. The high-frequency circuit according to claim 15, wherein said control circuit outputs a control bias voltage to said first and second low-noise amplifier circuits.