FET amplifier

About: FET amplifier is a research topic. Over the lifetime, 7048 publications have been published within this topic receiving 77549 citations.

High frequency power amplifier module

Abstract: For use in an amplifier configuration including a high-power amplifier and a low-power amplifier which are always interconnected in terms of high frequencies and between which switching is made using no switches, a highly stable high-frequency power amplifier module with high isolation between the amplifiers is provided. To reduce wrapping around from a low-power amplifier section in an activated state to a high-power amplifier section in a deactivated state or from the high-power amplifier section in an activated state to the low-power amplifier section in a deactivated state, an input matching circuit having high isolation characteristics is included in an input matching circuit portion which does not have much to do with amplifier efficiency. Switching of each of the amplifier sections between an activated state and a deactivated state is effected by control using bias input terminals.

A 0.85 THz vacuum-based power amplifier

Abstract: A 0.850 THz vacuum electronic power amplifier capable of >100mW output power is being developed at Northrop Grumman Electronic Systems. The compact power amplifier is based on a DRIE-fabricated folded waveguide slow-wave circuit, together with a high current density thermionic cathode, a high field permanent magnet solenoid, and a single-stage depressed collector for overall device efficiency. The new 0.85 THz power amplifier design is based on a 0.67 THz amplifier that achieved over 100mW of output power with 21.5 dB of gain, 15 GHz of operational bandwidth, a collector efficiency of 93% and an overall device efficiency of 0.44%.

Offset adjustment circuit

Abstract: An offset adjustment circuit for a differential amplifier includes a current source connected in series with a resistor for establishing a biasing voltage for a pair of field effect transistors (FET) having variable resistors in their biasing circuits. These FET's are connected to introduce currents respective connections between an input stage and a second stage of the differential amplifier. The difference of the currents supplied by the FET's divided by the transconductance of the input stage of the differential amplifier corresponds to an offset which remains fixed with changes in temperature. The offset introduced by the FET's, as determined by the adjusted values of the resistors in their biasing circuits, may be in opposition to the offset of the differential amplifier to either reduce it partially or completely, or it may be additive to the offset of the differential amplifier, as desired.

Method and apparatus for improving intermodulation in a feed-forward amplifier

Abstract: A feed-forward amplifier (600) has an error path (123) replaced by a feed-forward amplifier (603) in a nested feed-forward configuration. By replacing the error path (123) with the feed-forward amplifier (603), design parameters such as efficiency and power output which are difficult to achieve with the conventional error path (123) are easily achieved with the single loop feed-forward amplifier (603). In this configuration, the main path (613) of the feed-forward amplifier (603) is capable of operating in a more efficient Class AB mode while still operating over a large dynamic range with to provide a relatively constant gain/phase relationship, thus insuring good intermodulation performance. The error path (627) of the feed-forward amplifier (603) must still be biased Class A, but it's requirements are much less than those of a Class A error amplifier (124) in an un-nested configuration.