The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 27, 1992
Filed:
Jul. 16, 1991
Fujitsu Limited, Kawasaki, JP;
Fujitsu Yamanashi Electronics Limited, Yamanashi, JP;
Abstract
A high efficiency RF power amplifier includes a field effect transistor having a grounded source, a gate receiving an input signal, and a drain. A first inductor has a first end coupled to the drain via a lead inductance, and a second end through which an amplified output signal is output. A first capacitor has a first end grounded and a second end coupled to the second end of the first inductor. A second inductor has a first end receiving a drain bias voltage and a second end coupled to the second end of the first inductor. The second inductor is formed of a distributed-constant element. The first capacitor and the second inductor form a parallel resonant circuit coupled to the drain at a fundamental operating frequency of the high efficiency RF power amplifier, so that the drain is set to a high-impedance state. The first inductor, the first capacitor and the lead inductance form a serial resonant circuit coupled to the drain at a second harmonic of the fundamental operating frequency, so that the drain is set to a low-impedance state.