High-frequency power amplifier

• US 5,274,341 A
• Filed: 07/17/1992
• Issued: 12/28/1993
• Est. Priority Date: 07/19/1991
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd., Space Communications Research Corporation
• Original Assignee: Hitachi, Ltd., Space Communications Research Corporation
• Inventors: Iso, Akio, Funaki, Haruhiko, Masuda, Nobuo, Sekine, Kenji, Ohnishi, Masami
• Primary Examiner(s): Mullins, James B.
• Application Number:
  US07/914,408
• Time in Patent Office: 529 Days
• Field of Search: 330/55, 330/124 R, 330/251, 330/269, 330/277, 330/295, 330/306
• US Class Current: 330/269
• CPC Class Codes: H03F 3/604 using FET's

Abstract

A high-frequency power amplifier comprises a pair of FETs, a divider which supplies opposite-phase versions of a signal to be amplified to the FETs, distributed-parameter transmission lines connected respectively at one ends thereof to output electrodes of the FETs, and a combiner which combines signals appearing at another ends of the transmission lines into a signal of a common phase. Stubs which short-circuit for even harmonics included in output signals of the FETs are connected respectively to the transmission lines at positions distant from the output electrodes of the FETs by a multiple of a quarter wavelength of the fundamental wave included in the output signals of the FETs. A first capacitor is connected between the transmission lines at positions distant from the output electrodes of the FETs by the 1/12 wavelength of the fundamental wave included in the output signals of the FETs so that the output electrodes of the FETs are open for the third harmonic, and a second capacitor is connected between the transmission lines at positions between the connecting positions of the first capacitor and the connecting positions of the stubs so as to perform impedance matching for the fundamental wave included in the output signals of the FETs.

Claims

1. A high-frequency power amplifier comprising:

a pair of amplifying devices;

a divider which supplies opposite-phase versions of a signal to be amplified to said amplifying devices;

transmission lines connected respectively at one ends thereof to output electrodes of said amplifying devices;

stubs connected respectively to said transmission lines at positions distant from the output electrodes of said amplifying devices by a multiple of a quarter wavelength of a fundamental wave included in output signals of said amplifying devices, and adapted to shortcircuit for a frequency twice the frequency of the fundamental wave included in the output signals of said amplifying devices;

a capacitor connected between said transmission lines, said capacitor providing a load impedance matching to said pair of amplifying devices for the fundamental wave included in the output signals of said amplifying devices; and

a combiner which combines signals appearing at another ends of said transmission lines into a signal of a common phase.

2. A high-frequency power amplifier according to claim 1, further comprising another capacitor connected between the transmission lines, and wherein said capacitor is connected at positions intermediate connecting positions of the another capacitor and connecting positions of the stubs.

4. A high-frequency power amplifier comprising:

a pair of amplifying devices;

a divider which supplies opposite-phase versions of a signal to be amplified to said amplifying devices;

transmission lines connected respectively at one ends thereof to output electrodes of said amplifying devices;

stubs connected respectively to said transmission lines at positions distant from the output electrodes of said amplifying devices by a multiple of a quarter wavelength of a fundamental wave included in output signals of said amplifying devices, and adapted to short-circuit for a frequency twice the frequency of the fundamental wave included in the output signals of said amplifying devices;

a first capacitor connected between said transmission lines at positions distant from the output electrodes of said amplifying devices by the 1/12 wavelength of the fundamental wave included in the output signals of said amplifying devices;

a second capacitor connected between said transmission lines at positions between the connecting positions of said first capacitor and the connecting positions of said stubs; and

a combiner which combines signals appearing at another ends of said transmission lines into a signal of a common phase.

5. A high-frequency power amplifier comprising:

a pair of amplifying devices;

a divider which supplies opposite-phase versions of a signal to be amplified to said amplifying devices;

transmission lines connected respectively at one ends thereof to output electrodes of said amplifying devices;

stubs connected respectively to said transmission lines at positions distant from the output electrodes of said amplifying devices by a multiple of a quarter wavelength of a fundamental wave included in output signals of said amplifying devices, and adapted to short-circuit for a frequency twice the frequency of the fundamental wave included in the output signals of said amplifying devices;

a resonance circuit connected between said transmission lines at positions distant from the output electrodes of said amplifying devices by the 1/12 wavelength of the fundamental wave included in the output signals of said amplifying devices, and adapted to behave parallel resonation at the frequency of the fundamental wave included in the output signals of said amplifying devices;

a capacitor connected between said transmission lines at positions between the connecting positions of said resonance circuit and the connecting positions of said stubs; and

a combiner which combines signals appearing at another ends of said transmission lines into a signal of a common phase.

3. A high-frequency power amplifier according to claim 5, wherein said another capacitor is connected between the transmission lines at positions distant from the output electrodes of said amplifying devices by the 1/12 wavelength of the fundamental wave included in the output signals of said amplifying devices.

6. A high-frequency power amplifier comprising:

a pair of amplifying devices;

a divider which supplies opposite-phase versions of a signal to be amplified to said amplifying devices;

transmission lines connected respectively at one ends thereof to output electrodes of said amplifying devices;

resonance circuits connected respectively on said transmission lines at positions distant from the output electrodes of said amplifying devices by a quarter wavelength of a fundamental wave included in output signals of said amplifying devices, and adapted to behave parallel resonation at the frequency of the fundamental wave included in the output signals of said amplifying devices;

a capacitor connected between said transmission lines; and

a combiner which combines signals appearing at another ends of said transmission lines into a signal of a common phase.