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 amplifier, receiver, and transmitter system

Abstract: An amplifier is equipped with an input terminal and an output terminal and has a transistor as an amplifying element, said amplifier comprising: a negative feedback circuit provided in said transistor; and a parallel circuit which includes an inductive element and a resistive element connected in series between the input terminal of said amplifier and an input terminal of said transistor, or between the output terminal of said amplifier and an output terminal of said transistor.

Distributed amplifier using dual-gate GaAs FET's

Abstract: A 2-18 gigahertz monolithic distributed amplifier using dual-gate gallium arsenide field effect transistors for maximum gain over the design bandwidth.

Balanced differential amplifier

Abstract: In a balanced differential amplifier, a constant current source MOS FET operable in an unsaturated region is usually incorporated. When noise is inputted to the differential amplifier, the current source FET undergoes an influence of noise level superposed upon the input signal DC voltage thereof, thus deteriorating the constant current characteristics. To overcome this problem, a pair of current source MOS FETs are additionally incorporated therewith. Since the two current source MOS FETs operate near a boundary between saturated and unsaturated regions and further the gate voltages applied thereto varies in out-of-phase relationship to each other in response to input signal fluctuations, it is possible to keep constant the sum total of two currents flowing through the two constant current MOS FETs, thus improving the overall constant current characteristics and therefore the suppression capability against noise inputted in phase to the amplifier.

Output power performance of dual‐fed and single‐fed distributed amplifiers

Abstract: It is well known that the dual-fed distributed amplifier utilizes all FET output power, whereas up to a half is wasted in the single-fed distributed amplifier. We show that both the single-fed and antiphase-input dual-fed distributed amplifiers are able to achieve power equalization among the FETs at microwave frequencies when the FETs are spaced 180°. Such power equalization allows identical (and optimum) load lines for all FETs. The dual-fed amplifier has the added advantage of being less affected by losses. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 27: 281–284, 2000.

Apparatus and method for combining output signals from parallelly coupled power field effect transistors in high frequency amplifiers

Abstract: Apparatus and method for parallel operation of radio frequency transistor amplifier circuits in a Class D mode of operation at radio frequency signal ranges without the use of frequency limiting components is disclosed. A driver circuit provides the input signals for each radio frequency transistor amplifier circuit. A transformer is disclosed that combines the output signals of the radio frequency transistor amplifier circuits while matching the amplifier circuit impedance and the transformer load impedance (i.e., the antenna impedance). The transformer eliminates the need for DC blocking capacitors between the primary and secondary windings of the transformer. The transformer/power combiner includes a plurality of (1:1) transformer units having the unit input terminals (power amplifier output signals) coupled in parallel and having unit output terminals coupled in series. The parallel/series configuration permits impedance matching of the power amplifier output impedance and impedance driven by the transformer. The primary structure of the unit transformer is metal sleeve surrounded by a ferrite core. The secondary winding includes at least one conductor cable inserted through the metal sleeve. The metal sleeve is coupled between the power amplifier output terminal and the DC power source.