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:
Dec. 21, 1999
Filed:
Jul. 07, 1997
Edward L Griffin, Roanoke, VA (US);
Dain Curtis Miller, Roanoke, VA (US);
Inder J Bahl, Roanoke, VA (US);
ITT Corporation, New York, NY (US);
Abstract
Disclosed is an improved field effect transistor (FET) employing both a metal-semiconductor (MES) gate and a metal-insulator-semiconductor (MIS) gate, which FET is particularly useful to provide amplification at microwave frequencies. The use of the MIS gate with appropriate biasing allows the carrier density within a selected portion of the device's channel region to be controlled. The carrier density control increases the breakdown voltage of the FET and enables the FET to be operated with higher maximum channel current and a higher drain to source voltage. As a result, higher output power is provided as compared to prior art MESFET devices of a similar size. Also disclosed is an amplifier circuit including the MES/MIS FET of the present invention, which amplifier circuit further includes means coupled to the MES/MIS FET for dividing a high frequency input signal to provide a first divided portion and a second divided portion. The first divided portion is applied to the MES gate while the second divided portion is applied to the MIS gate. The second portion operates as a time varying bias voltage to control carrier density within the channel portion of the MES/MIS FET and thereby control performance parameters such as breakdown voltage and maximum available channel current.