| US 7,541,874 B2 | ||
| High-frequency power amplifier device | ||
| Masahiro Maeda, Osaka (Japan); Katsuhiko Kawashima, Hyogo (Japan); and Masatoshi Kamitani, Osaka (Japan) | ||
| Assigned to Panasonic Corporation, Osaka (Japan) | ||
| Filed on Mar. 28, 2007, as Appl. No. 11/727,692. | ||
| Claims priority of application No. 2006-091207 (JP), filed on Mar. 29, 2006. | ||
| Prior Publication US 2007/0229170 A1, Oct. 04, 2007 | ||
| Int. Cl. H03F 3/04 (2006.01) | ||
| U.S. Cl. 330—302 [330/296] | 16 Claims |
| 1. A high-frequency power amplifier device comprising:
a power amplifier transistor which amplifies a high-frequency signal;
an output matching circuit connected to an output side of said power amplifier transistor;
an impedance conversion circuit connected to an output side of said output matching circuit; and
a high-frequency element connected to an output side of said impedance conversion 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 element viewed from an output terminal of 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,
Δf/fM is 0.05 or above, where Δf denotes a frequency bandwidth of said high-frequency power amplifier device and fM denotes
a center value of the frequency, and
said impedance conversion circuit is set so that a voltage standing wave ratio (VSWR) standardized by an impedance of the
output side of said power amplifier transistor is smaller than a VSWR of an impedance of the output side of said impedance
conversion circuit viewed from an output terminal of said impedance conversion circuit, the impedance of the output side of
said power amplifier transistor being viewed from an output terminal of said power amplifier transistor and corresponding
to a center value of an impedance of the frequency.
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