Raytheon Company

David R Fletcher

David D Heston

John G Heston

Gordon R Scott

Scott Mitchel Heston

Brian P Helm

William Sheridan Kopp

Off-chip distributed drain biasing increases output power and efficiency for high power distributed amplifier MMICs. An off-chip bias circuit has a common input for receiving DC bias current and a plurality of parallel-connected bias chokes among which the DC bias current is divided. The chokes are connected to a like plurality of drain terminals at different FET amplifier stages to supply DC bias current at different locations along the output transmission line. Off-chip distributed drain biasing increases the level of DC bias current that can be made available to the amplifier and add inductances to selected FET amplifier stages, typically the earlier stages, to modify the load impedance seen at the drain terminal to better match the amplifier stages to improve power and efficiency.

Off-chip distributed drain biasing of high power distributed amplifier monolithic microwave integrated circuit (MMIC) chips

According to one embodiment of the present invention a method for biasing a power amplifier having at least one transistor exhibiting kink anomaly includes providing a bias circuit coupled to a gate of at least one transistor of the power amplifier. The method also includes providing, by the bias circuit, a bias voltage to the gate. The bias circuit has a load characteristic that intersects a current versus gate voltage curve for the gate at a frequency of operation of the power amplifier only once and that exhibits a low impedance at the intersection of the load characteristic with the current versus gate curve of the gate.

Method and system for biasing power amplifiers with kink anomaly

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Allen, TX, United States of America

David R Fletcher