Impedance matching circuit for power amplifier

• US 5,969,582 A
• Filed: 07/03/1997
• Issued: 10/19/1999
• Est. Priority Date: 07/03/1997
• Status: Expired due to Term

• Current Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Original Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: Conroy, Kevin P., Boesch, Ronald D.
• Primary Examiner(s): Bettendorf, Justin P.
• Application Number:
  US08/888,168
• Time in Patent Office: 838 Days
• Field of Search: 333/129, 333/132, 333/175
• US Class Current: 333/129
• CPC Class Codes: H03F 1/56 Modifications of input or output impedances, not otherwise provided for
• CPC Class Codes: H03F 2200/111 the amplifier being a dual or triple band amplifier, e.g. 900 and 1800 MHz, e.g. switched or not switched, simultaneously or not
• CPC Class Codes: H03F 2200/387 A circuit being added at the output of an amplifier to adapt the output impedance of the amplifier
• CPC Class Codes: H03F 3/24 of transmitter output stages
• CPC Class Codes: H03H 11/30 Automatic matching of source impedance to load impedance
• CPC Class Codes: H03H 7/38 Impedance-matching networks
• CPC Class Codes: H03H 7/46 Networks for connecting several sources or loads, working on different frequencies or frequency bands, to a common load or source for use in multiplex transmission systems H04J1/00
• CPC Class Codes: H04B 1/005 adapting radio receivers, transmitters andtransceivers for operation on two or more bands, i.e. frequency ranges
• CPC Class Codes: H04B 1/0458 Arrangements for matching and coupling between power amplifier and antenna or between amplifying stages matching circuits in general H03H
• CPC Class Codes: H04B 1/406 with more than one transmission mode, e.g. analog and digital modes

Abstract

An impedance matching circuit for a multi-band power amplifier has an input port for receiving RF signals from an amplifier, a first path for communicating RF signals in a first frequency band to a first output port, and at least one second path for communicating RF signals in a second frequency band to a second output port. The first path includes impedance matching circuitry for matching the impedance of the first output port and the input port in the first frequency band, and the second path includes impedance matching circuitry for matching the impedance of the second output port and the input port in the second frequency band. The first path contains circuitry which blocks RF signals in the second frequency band, and the second path contains circuitry which blocks RF signals in the first frequency band. A multiband power amplifier includes a multi-band amplifier coupled with an impedance matching circuit for a multiband power amplifier.

Claims

1. An impedance matching circuit, comprising:

an input port for receiving RF signals in at least a first frequency band and a second frequency band, a first output port, and a second output port;

a first path for communicating RF signals in the first frequency band to said first output port; and

a second path for communicating RF signals in the second frequency band to a second output port;

wherein said first path includes first means for blocking RF signals in the second frequency band from being communicated to said first output port and for matching the impedance between said input port and said first output port for RF signals in the first frequency band; and

wherein said first path includes a reactive element which contributes to the impedance match of RF signals in said second frequency band;

wherein said first blocking means comprises a parallel resonant circuit tuned to present a substantially open circuit to RF signals at a predetermined frequency in said second frequency band; and

a shunt circuit including a capacitor and an inductor, said shunt circuit coupled to said first output port, wherein said parallel resonant circuit, and said shunt circuit operatively form an impedance matching network for RF signals in said first frequency band.

2. An impedance matching circuit, comprising:

an input port for receiving RF signals in at least a first frequency band and a second frequency band, a first output port, and a second output port;

a first path for communicating RF signals in the first frequency band to said first output port; and

a second path for communicating RF signals in the second frequency band to a second output port;

wherein said first path includes first means for blocking RF signals in the second frequency band from being communicated to said first output port and for matching the impedance between said input port and said first output port for RF signals in the first frequency band; and

wherein said first path includes a reactive element which contributes to the impedance match of RF signals in said second frequency band;

wherein said second path includes second means for blocking RF signals in the first frequency band from being communicated to said second output port; and

wherein said first blocking means comprises a parallel resonant circuit selected to present an open circuit to signals in said second frequency band and said second blocking means includes a parallel resonant circuit selected to present substantially an open circuit to signals in said first frequency band, for blocking signals in said second frequency band from being communicated to said first output port and for blocking signals in said first frequency band from being communicated to said second output port, respectively.

3. An impedance matching circuit, comprising:

an input port for receiving RF signals in at least a first frequency band and a second frequency band a first output port, and a second output port;

a first path for communicating RF signals in the first frequency band to said first output port; and

a second path for communicating RF signals in the second frequency band to a second output port;

wherein said first path includes first means for blocking RF signals in the second frequency band from being communicated to said first output port and for matching the impedance between said input port and said first output port for RF signals in the first frequency band; and

wherein said first path includes a reactive element which contributes to the impedance match of RF signals in said second frequency band;

wherein said second path includes second means for blocking RF signals in the first frequency band from being communicated to said second output port;

wherein said first blocking means comprises a series resonant circuit selected to present substantially a short circuit to signals in said second frequency band and said second blocking means comprises a parallel resonant circuit selected to present substantially an open circuit to signals in said first frequency band, for blocking signals in said second frequency band from being communicated to said first output port and for blocking signals in said first frequency band from being communicated to said second output port, respectively; and

wherein said first path further comprises a series inductor and a shunt capacitor selected to provide a high pass filter network.

4. An impedance matching circuit, comprising:

an input port for receiving RF signals in at least a first frequency band and a second frequency band, a first output port, and a second output port;

a first path for communicating RF signals in the first frequency band to said first output port; and

a second path for communicating RF signals in the second frequency band to a second output port;

wherein said first path includes first means for blocking RF signals in the second frequency band from being communicated to said first output port and for matching the impedance between said input port and said first output port for RF signals in the first frequency band; and

wherein said first path includes a reactive element which contributes to the impedance match of RF signals in said second frequency band;

wherein said first path comprises a low pass filter; and

wherein said second path comprises a low pass filter.

5. An impedance matching circuit comprising:

an input port for receiving RF signals in at least a first frequency band and a second frequency band, a first output port, and a second output port;

a first path for communicating RF signals in the first frequency band to said first output port; and

a second path for communicating RF signals in the second frequency band to a second output port;

wherein said first path includes first means for blocking RF signals in the second frequency band from being communicated to said first output port and for matching the impedance between said input port and said first output port for RF signals in the first frequency band; and

wherein said first path includes a reactive element which contributes to the impedance match of RF signals in said second frequency band;

wherein said second path includes second means for blocking RF signals in the first frequency band from being communicated to said second output port; and

wherein said second blocking means comprises a parallel resonant circuit selected to present an open circuit to signals in said first frequency band,

said second path includes a shunt circuit having an impedance selected such that said shunt circuit appears as a shunt inductance to RF signals in said second frequency band, and wherein said parallel resonant circuit and said shunt circuit operatively form a high pass impedance matching network for RF signals in said second frequency band.

6. An impedance matching circuit comprising:

an input port for receiving RF signals in a first frequency band and a second frequency band, a first output port and a second output port;

a first path for communicating RF signals in the first frequency band to said first output port; and

a second path for communicating RF signals in the second frequency band to said second output port;

wherein said first path comprises;

a parallel resonant circuit tuned to present substantially an open circuit to RF signals within said second frequency band and a series inductance to RF signals within said first frequency band,

a first shunt capacitor coupled to said input port, and

a second shunt capacitor coupled to said first output port;

wherein said parallel resonant circuit and said first and second shunt capacitors operatively form a low pass impedance matching network for RF signals in said first frequency range, and

wherein said second path comprises;

a first series capacitor coupled to said input port,

a third shunt capacitor coupled to said second output port,

a first series inductor coupled to said second output port, and

a shunt series resonant circuit tuned to present a short circuit to RF signals in said first frequency band and a shunt inductance to RF signals in said second frequency band, said shunt series resonant circuit coupled between said first series capacitor and said first series inductor;

wherein said first series capacitor, said first and third shunt capacitors, said series inductor and said shunt series resonant circuit operatively form an impedance matching network for RF signals in said second frequency range; and

wherein said first series capacitor operatively contributes to the impedance match of said low pass matching network for RF signals in said first frequency band.

7. An impedance matching circuit comprising:

an input port for receiving RF signals in a first frequency band and a second frequency band, a first output port and a second output port;

a first path for communicating RF signals in the first frequency band to said first output port; and

a second path for communicating RF signals in the second frequency band to said second output port;

wherein said first path comprises;

a parallel resonant circuit tuned to present substantially an open circuit to RF signals within said second frequency band and a series inductance to RF signals within said first frequency band,

a first shunt capacitor coupled to said input port, and

a second shunt capacitor coupled to said first output port;

wherein said parallel resonant circuit and said first and second shunt capacitors operatively form a low pass impedance matching network for RF signals in said first frequency range, and

wherein said second path comprises;

a parallel resonant circuit tuned to present substantially an open circuit to RF signals within said first frequency band and a series capacitance to RF signals within said second frequency band, and

a shunt circuit comprising an inductor and a capacitor coupled to said second output port;

wherein said first shunt capacitor, said shunt circuit and said parallel resonant circuit operatively form an impedance matching network for RF signals in said second frequency band.

8. An impedance matching circuit comprising:

an input port for receiving RF signals in a first frequency band and a second frequency band, a first output port and a second output port;

a first path for communicating RF signals in the first frequency band to said first output port; and

a second path for communicating RF signals in the second frequency band to said second output port;

wherein said first path comprises;

a first parallel resonant circuit tuned to present substantially an open circuit to RF signals within said second frequency band and a series inductance to RF signals within said first frequency band,

a first shunt capacitor coupled to said input port, and

a second shunt capacitor coupled to said first output port;

wherein said first parallel resonant circuit and said first and second shunt capacitors operatively form a low pass impedance matching network for RF signals in said first frequency range, and

wherein said second path comprises;

a second parallel resonant circuit tuned to present substantially an open circuit to RF signals within said first frequency band and a series capacitance to RF signals within said second frequency band, and

a series inductor coupled to said parallel resonant circuit and third shunt capacitor coupled to said second output port;

wherein said first and third shunt capacitors, said series inductor and said second parallel resonant circuit operatively form an impedance matching network for RF signals in said second frequency band.