Bypass filter, multi-band antenna switch circuit, and layered module composite part and communication device using them

• US 7,057,472 B2
• Filed: 08/12/2002
• Issued: 06/06/2006
• Est. Priority Date: 08/10/2001
• Status: Active Grant

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Hitachi Metals (Thailand) Ltd.
• Inventors: Watanabe, Mitsuhiro, Fukamachi, Keisuke, Kemmochi, Shigeru, Yokouchi, Satoru, Tai, Hiroyuki, Taketa, Tsuyoshi
• Primary Examiner(s): TAKAOKA, DEAN O
• Application Number:
  US10/486,326
• Publication Number:
  US 20040266378A1
• Time in Patent Office: 1,394 Days
• Field of Search: 333/101, 333/104, 333/132, 333/133, 333/185
• US Class Current: 333/101
• CPC Class Codes: H03H 2001/0085 Multilayer, e.g. LTCC, HTCC, green sheets inside PCB filters H05K
• CPC Class Codes: H03H 7/0115 comprising only inductors and capacitors H03H7/075, H03H7/09, H03H7/12, H03H7/13 take precedence
• CPC Class Codes: H03H 7/0153 Electrical filters; Controlling thereof
• CPC Class Codes: H03H 7/1758 Series LC in shunt or branch path H03H7/1791 takes precedence
• CPC Class Codes: H03H 7/1766 Parallel LC in series path H03H7/1783 takes precedence
• CPC Class Codes: H03H 7/1783 Combined LC in series path
• CPC Class Codes: H03H 7/465 having variable circuit topology, e.g. including switches
• CPC Class Codes: H04B 1/0057 using diplexing or multiplexing filters for selecting the desired band
• CPC Class Codes: H04B 1/006 using switches for selecting the desired band H04B1/0057 takes precedence
• CPC Class Codes: H04B 1/406 with more than one transmission mode, e.g. analog and digital modes
• CPC Class Codes: H04B 1/44 Transmit/receive switching
• CPC Class Codes: H04B 1/48 in circuits for connecting transmitter and receiver to a common transmission path, e.g. by energy of transmitter H04B1/46 takes precedence
• CPC Class Codes: H04B 1/52 Hybrid arrangements, i.e. arrangements for transition from single-path two-direction transmission to single-direction transmission on each of two paths or vice versa

Abstract

A multi-band antenna switch circuit including a diplexer connected to an antenna terminal for demultiplexing signals of different passing bands, a first and a second switch circuit for switching a high frequency signal and a low frequency signal demultiplexed by the diplexer to a plurality of transmission/reception terminals, a first and a second low pass filter connected to a transmission path between the diplexer and the transmission terminal or between the first and the second switch circuit and the transmission terminal, and a notch filter provided between the diplexer and the first switch circuit or between the diplexer and the second switch circuit. The multi-band antenna switch circuit includes a high pass filter having an input terminal and an output terminal and provided at least between die diplexer and the antenna terminal and including a first inductor connected between the input terminal and the ground, a first capacitor connected between the input terminal and the output terminal, a second inductor connected to the output terminal, and a second capacitor connected between the second inductor and the ground.

Claims

1. A filter circuit comprising a highpass filter and a serial resonance circuit between an input terminal and an output terminal,

wherein said highpass filter comprises a first inductor connected between said input terminal and a ground, a first capacitor connected between said input terminal and said output terminal, and said serial resonance circuit comprises a second inductor connected to said output terminal and a second capacitor connected to said second inductor and said ground, such that said serial resonance circuit'"'"'s resonance frequency is 100 to 500 MHz, whereby said serial resonance circuit is used for electrostatic surge measures.

2. The filter circuit according to claim 1, wherein a parallel resonance circuit comprising a third inductor and a third capacitor is disposed between said second inductor and said output terminal.

3. A multiband antenna switch circuit comprising a diplexer connected to an antenna terminal for branching signals having different passbands;

a first switch circuit for switching lower-frequency signals branched by said diplexer to plural transmitting/receiving terminals;

a second switch circuit for switching higher-frequency signals branched by said diplexer to plural transmitting/receiving terminals;

a first lowpass filter connected to a transmitting line between said diplexer and said transmission terminal or between said first switch circuit and said transmission terminal;

a second lowpass filter connected to a transmitting line between said diplexer and said transmission terminal or between said second switch circuit and said transmission terminal; and

a notch filter disposed between said diplexer and said first switch circuit and/or between said diplexer and said second switch circuit.

9. The multiband antenna switch circuit according to any one of claims 3 to 8, wherein it has an input terminal and an output terminal;

and wherein a highpass filter comprising a first inductor connected between said input terminal and a ground, a first capacitor connected between said input terminal and said output terminal, a second inductor connected to said output terminal, and a second capacitor connected to said second inductor and said ground is disposed in said circuit.

4. A multiband antenna switch circuit comprising a diplexer connected to an antenna terminal for branching signals having different passbands;

a first switch circuit for switching lower-frequency signals branched by said diplexer to a first transmission terminal and a first receiving terminal;

a second switch circuit for switching higher-frequency signals branched by said diplexer to a second transmission terminal, a second receiving terminal and a third transmitting/receiving terminal;

a first lowpass filter connected to a transmitting line between said diplexer and said first transmission terminal or between said first switch circuit and said first transmission terminal; and

a second lowpass filter connected to a transmitting line between said diplexer and said second transmission terminal or between said second switch circuit and said second transmission terminal, said diplexer and said second switch circuit being connected to each other via a notch filter.

7. The multiband antenna switch circuit according to claim 4, wherein a duplexer is connected to said third transmitting/receiving terminal.

10. The multiband antenna switch circuit according to claim 7, wherein a parallel resonance circuit comprising a third inductor and a third capacitor is disposed between the second inductor of said highpass filter and said output terminal.

5. A multiband antenna switch circuit comprising a diplexer for branching signals having different passbands;

a first switch circuit for switching lower-frequency signals branched by said diplexer to plural transmitting/receiving terminals;

a second switch circuit for switching higher-frequency signals branched by said diplexer to plural transmitting/receiving terminals;

a first lowpass filter connected to a transmitting line between said diplexer and a transmission terminal or between said first switch circuit and said transmission terminal; and

a second lowpass filter connected to a transmitting line between said diplexer and said transmission terminal or between said second switch circuit and said transmission terminal, wherein a notch filter is connected between said diplexer and said antenna terminal.

6. A multiband antenna switch circuit comprising a diplexer for branching signals having different passbands;

a first switch circuit for switching lower-frequency signals branched by said diplexer to a first transmission terminal and a first receiving terminal;

a second switch circuit for switching higher-frequency signals branched by said diplexer to a second transmission terminal, a second receiving terminal and a third transmitting/receiving terminal;

a first lowpass filter connected to a transmitting line between said diplexer and said first transmission terminal or between said first switch circuit and said first transmission terminal; and

a second lowpass filter connected to a transmitting line between said diplexer and said second transmission terminal or between said second switch circuit and said second transmission terminal, wherein a notch filter is connected between said diplexer and said antenna terminal.

8. The multiband antenna switch circuit according to claim 6, wherein a duplexer is connected to said third transmitting/receiving terminal.

11. A multiband antenna switch circuit comprising

a notch filter connected between a switch circuit and an antenna terminal;

(b) said switch circuit comprising at least a connection terminal connected to said notch filter, a first transmitting/receiving terminal and a second transmitting/receiving terminal;

(c) a first diplexer comprising a first common terminal connected to said first transmitting/receiving terminal, a first transmitting terminal and a second receiving terminal; and

(d) a second diplexer comprising a second common terminal connected to said second transmitting/receiving terminal, a second transmitting terminal and a first receiving terminal.

12. The multiband antenna switch circuit according to claim 11, wherein said notch filter comprises an inductor, a diode, a capacitor, a resistor and a power supply terminal, and its resonance frequency is adjustable by voltage applied to said power supply terminal.

13. The multiband antenna switch circuit according to claim 11, wherein said notch filter comprises an inverse voltage terminal for applying inverse voltage to said diode.

14. The multiband antenna switch circuit according to claim 12, wherein said notch filter comprises an inverse voltage terminal for applying inverse voltage to said diode.

15. The multiband antenna switch circuit according to any one of claims 11 to 14, wherein it comprises a highpass filter in said circuit;

and wherein said highpass filter comprises an input terminal, an output terminal, a first inductor connected between said input terminal and a ground, a first capacitor connected between said input terminal and said output terminal, a second inductor connected to said output terminal, and a second capacitor connected to said second inductor and said ground.

16. The multiband antenna switch circuit according to claim 15, wherein a parallel resonance circuit comprising a third inductor and a third capacitor is disposed between the second inductor of said highpass filter and said output terminal.

17. The multiband antenna switch circuit according to any one of claims 11 to 14, comprising a first lowpass filter connected to said first transmitting terminal, and a second lowpass filter connected to said second transmitting terminal.

18. The multiband antenna switch circuit according to any one of claims 11 to 14, wherein said switch circuit is formed by a GaAs semiconductor.

19. A composite laminate multiband antenna switch module constituted by a laminate comprising plural substrates, wherein part of transmission lines and capacitors constituting the multiband antenna switch circuit recited in any one of claims 3 to 8 and 11 to 14 are formed on substrates in said laminate;

and wherein switch elements, resistors, capacitors and inductors constituting part of said multiband antenna switch circuit are mounted onto said laminate as chip parts.

20. A communications device comprising the multiband antenna switch circuit recited in any one of claims 3 to 8 and 11 to 14.

21. A communications device comprising the composite laminate multiband antenna switch module recited in claim 19.