Low distortion amplifier and Doherty amplifier using low distortion amplifier

• US 8,149,060 B2
• Filed: 03/25/2008
• Issued: 04/03/2012
• Est. Priority Date: 03/25/2008
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Yamauchi, Kazuhisa, Noto, Hifumi, Inoue, Akira, Hamada, Tomokazu, Nakayama, Masatoshi, Horiguchi, Kenichi
• Primary Examiner(s): NGUYEN, PATRICIA T
• Application Number:
  US12/933,509
• Publication Number:
  US 20110012681A1
• Time in Patent Office: 1,470 Days
• Field of Search: 330/302, 330/238, 330/295
• US Class Current: 330/295
• CPC Class Codes: H03F 1/0288 using a main and one or several auxiliary peaking amplifiers whereby the load is connected to the main amplifier using an impedance inverter, e.g. Doherty amplifiers
• CPC Class Codes: H03F 1/3205 in field-effect transistor amplifiers
• CPC Class Codes: H03F 1/565 using inductive elements
• 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 2200/451 the amplifier being a radio frequency amplifier
• CPC Class Codes: H03F 3/195 in integrated circuits
• CPC Class Codes: H03F 3/601 using FET's, e.g. GaAs FET's H03F3/607, H03F3/608 take precedence

Abstract

Provided is a low distortion amplifier which can satisfy both securement of a setting space in a vicinity of a transistor and low impedance. The low distortion amplifier includes a short stub having a leading end thereof short-circuited with a high-frequency short-circuit element and a low-frequency short-circuit element, in which the short stub is connected to a vicinity of at least one of a gate terminal and a drain terminal of the transistor, and includes a plurality of branched lines, the plurality of branched lines each having a leading end thereof short-circuited with the high-frequency short-circuit element and the low-frequency short-circuit element.

Claims

1. A low distortion amplifier, comprising a short stub having a leading end thereof short-circuited with a high-frequency short-circuit element and a low-frequency short-circuit element,

wherein the short stub is connected to a vicinity of at least one of a gate terminal and a drain terminal of a transistor, and includes a plurality of branched lines, the plurality of branched lines each having a leading end thereof short-circuited with a high-frequency short-circuit element and a low-frequency short-circuit element.

2. A low distortion amplifier according to claim 1, wherein the low-frequency short-circuit element is disposed in a close vicinity of the high-frequency short-circuit element in each of the plurality of branched lines of the short stub.

3. A low distortion amplifier according to claim 1, wherein the plurality of branched lines of the short stub have the same line length from a connection point with a main line to the high-frequency short-circuit element.

4. A low distortion amplifier according to claim 1, wherein a plurality of the short stubs are connected to the vicinity of the at least one of the gate terminal and the drain terminal of the transistor.

5. A low distortion amplifier according to claim 1, wherein the short stub includes a line having different line widths between before and after branching.

6. A low distortion amplifier according to claim 1, wherein all or some of the plurality of branched lines of the short stub are bundled so as to form a part with a large line width, and the part is branched into a plurality of lines again just before short-circuited, the plurality of lines each having a leading end thereof short-circuited with the high-frequency short-circuit element and the low-frequency short-circuit element.

7. A low distortion amplifier according to claim 1, wherein the short stub is formed in a package of the transistor or formed integrally with the transistor on the same semiconductor.

8. A Doherty amplifier, which uses the low distortion amplifier according to claim 1, the low distortion amplifier being adopted as at least one of a carrier amplifier and a peak amplifier.

9. A Doherty amplifier, which uses the low distortion amplifier according to claim 2, the low distortion amplifier being adopted as at least one of a carrier amplifier and a peak amplifier.

10. A Doherty amplifier, which uses the low distortion amplifier according to claim 3, the low distortion amplifier being adopted as at least one of a carrier amplifier and a peak amplifier.

11. A Doherty amplifier, which uses the low distortion amplifier according to claim 4, the low distortion amplifier being adopted as at least one of a carrier amplifier and a peak amplifier.

12. A Doherty amplifier, which uses the low distortion amplifier according to claim 5, the low distortion amplifier being adopted as at least one of a carrier amplifier and a peak amplifier.

13. A Doherty amplifier, which uses the low distortion amplifier according to claim 6, the low distortion amplifier being adopted as at least one of a carrier amplifier and a peak amplifier.

14. A Doherty amplifier, which uses the low distortion amplifier according to claim 7, the low distortion amplifier being adopted as at least one of a carrier amplifier and a peak amplifier.