High-frequency power amplifier device

Abstract

A high-frequency power amplifier device including: a power amplifier circuit which amplifies a high-frequency signal; an output matching circuit connected to an output side of the power amplifier circuit; and a high-frequency circuit connected to an output side of the output matching circuit, which is designed so that X[f] satisfies the relationship expressed as X[L]

Description

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects, advantages and features of the invention will become apparent from the following description thereof taken in conjunction with the accompanying drawings that illustrate a specific embodiment of the invention. In the Drawings:

FIG. 1 is a diagram showing an outline of the conventional power amplifier illustrated as a first example;

FIG. 2 is a diagram showing the structure of the conventional power amplifier illustrated as the first example;

FIG. 3 is a table listing the characteristics of the conventional power amplifier illustrated as the first example;

FIG. 4 is a Smith chart showing the impedance ZL (TR) as an impedance of an output matching circuit viewed from an output end of a rear stage HBT included in the power amplifier illustrated as a second example;

FIG. 5 is a table listing the characteristics of the power amplifier illustrated as the second example;

FIG. 6 is a diagram showing an outline of a high-frequency power amplifier device which includes a conventional power amplifier illustrated as a third example;

FIG. 7 is a Smith chart showing an input impedance of an isolator connected to an output terminal of the power amplifier illustrated as the third example;

FIG. 8 is a Smith chart showing the impedance ZL (TR) as an impedance of an output matching circuit viewed from an output terminal of a rear stage HBT included in the power amplifier illustrated as the third example;

FIG. 9 is a table listing the characteristics of the power amplifier illustrated as the third example;

FIG. 10 is a diagram showing an outline of the high-frequency power amplifier device according to a first embodiment of the present invention;

FIG. 11 is a Smith chart showing the impedance ZL (PA) as an impedance of a phase shift circuit viewed from an output terminal of a power amplifier;

FIG. 12 is a Smith chart showing the impedance ZL (TR) as an impedance of an output matching circuit viewed from an output end of a rear stage HBT;

FIG. 13 is a diagram showing impedance conversion from impedance ZL (PA) to impedance ZL (TR);

FIG. 14 is a diagram showing a table listing the characteristics of the high-frequency power amplifier device according to the first embodiment;

FIG. 15 is a Smith chart showing the impedance ZL (PA) in the case of setting a phase rotation by a phase shift circuit to −90 degrees;

FIG. 16 is a Smith chart showing the impedance ZL (TR) as an impedance of an output matching circuit viewed from an output end of a rear stage HBT;

FIG. 17 is a diagram showing an outline of the high-frequency power amplifier device according to a second embodiment of the present invention;

FIG. 18 is a diagram showing an outline of the high-frequency power amplifier device according to a third embodiment of the present invention;

FIG. 19 is a Smith chart showing the impedance ZL (PA) in the case of setting a phase rotation by a phase shift circuit to 90 degrees;

FIG. 20 is a Smith chart showing the impedance ZL (TR) as an impedance of an output matching circuit viewed from an output end of a rear stage HBT;

FIG. 21 is a diagram showing an outline of the high-frequency power amplifier device according to a fourth embodiment of the present invention;

FIG. 22 is a Smith chart showing an input impedance of an isolator according to a fifth embodiment of the present invention;

FIG. 23 is a Smith chart showing the impedance ZL (PA) as an impedance of a phase shift circuit viewed from an output terminal of a power amplifier;

FIG. 24 is a Smith chart showing the impedance ZL (TR) as an impedance of an output matching circuit viewed from an output end of a rear stage HBT;

FIG. 25 is a diagram showing a table listing the characteristics of the high-frequency power amplifier device according to the fifth embodiment;

FIG. 26 is a diagram showing an outline of the high-frequency power amplifier device according to a sixth embodiment of the present invention; and

FIG. 27 is a diagram showing an outline of the high-frequency power amplifier device according to a seventh embodiment of the present invention.

Claims

1. A high-frequency power amplifier device comprising: a power amplifier circuit which amplifies a high-frequency signal;an output matching circuit connected to an output side of said power amplifier circuit; anda high-frequency circuit connected to an output side of said output matching circuit,wherein said high-frequency power amplifier device is designed so that X[f] satisfies X[L]<X[H], where j denotes an imaginary number, f denotes a frequency, an impedance of said high-frequency circuit viewed from said output matching circuit is defined as Z[f]=R[f]+jX[f], L denotes a lower limit of the frequency, and H denotes an upper limit of the frequency.

2. The high-frequency power amplifier device according to claim 1, wherein said high-frequency power amplifier device is designed so that X[f] satisfies X[L]<X[M]<X[H], where M denotes a center value of the frequency.

3. The high-frequency power amplifier device according to claim 1, wherein said high-frequency power amplifier device is designed so that R[f] satisfies R[L]<R[H].

4. The high-frequency power amplifier device according to claim 1, wherein X[L] is a negative value and X[H] is a positive value.

5. The high-frequency power amplifier device according to claim 1, wherein said high-frequency power amplifier device is designed so that a voltage standing wave ratio at an output end of said power amplifier circuit is less than a voltage standing wave ratio at an output end of said output matching circuit.

6. The high-frequency power amplifier device according to claim 1, wherein said high-frequency circuit is an isolator which transmits high-frequency power only to an output side of said isolator.

7. The high-frequency power amplifier device according to claim 1, wherein said high-frequency circuit is a phase shift circuit which shifts a phase to a predetermined value.

8. The high-frequency power amplifier device according to claim 7, wherein said high-frequency power amplifier device is designed so that X1[f] satisfies X1 [L]>X1[H], where an impedance of said phase shift circuit viewed from an output terminal is defined as Z1[f]=R1[f]+jX1[f].

9. The high-frequency power amplifier device according to claim 7, wherein said high-frequency power amplifier device is designed so that the impedance at an output end of said phase shift circuit results from rotating an impedance at an output end of said power amplifier circuit by −90 degrees or less, or 90 degrees or more at a center value of the frequency.

10. The high-frequency power amplifier device according to claim 7, wherein in said high-frequency power amplifier device, said power amplifier circuit, said output matching circuit and said phase shift circuit are configured in a same package.

11. The high-frequency power amplifier device according to claim 7, wherein said high-frequency power amplifier device is designed so that Δf/fM is 0.05 or above, where Δf denotes a frequency bandwidth and fM denotes a center value of the frequency.

12. The high-frequency power amplifier device according to claim 7, wherein said phase shift circuit is configured of a capacitor connected in series to a signal line, and an inductor connected between the signal line and a ground.

13. The high-frequency power amplifier device according to claim 7, wherein said phase shift circuit is configured of an inductor connected in series to a signal line, and a capacitor connected between the signal line and a ground.

14. The high-frequency power amplifier device according to claim 1, wherein said high-frequency circuit is configured of a phase shift circuit, connected to the output side of said output matching circuit, which shifts a phase to a predetermined value, and an isolator, connected to the output side of said phase shift circuit, which transmits high-frequency power only to an output side of said isolator.

15. The high-frequency power amplifier device according to claim 14, wherein said high-frequency power amplifier device is designed so that X1[f] satisfies X1 [L]>X1[H], where an impedance of said isolator viewed from said phase shift circuit is defined as Z1[f]=R1[f]+jX1[f].

16. The high-frequency power amplifier device according to claim 14, wherein in said high-frequency power amplifier device, said phase shift circuit and said isolator are configured in a same package.

17. The high-frequency power amplifier device according to claim 14, wherein said high-frequency power amplifier device is designed so that a 1.7 GHz band and a 1.9 GHz band are included in a frequency bandwidth.

18. The high-frequency power amplifier device according to claim 14, wherein said high-frequency power amplifier device is designed so that a 800 MHz band and a 900 MHz band are included in a frequency bandwidth.