Monolithic high-voltage FET power amplifiers

Abstract

High-voltage field-effect transistor (HVYET) power amplifiers offer improved system efficiency through reduced DC power distribution loss and more efficient DC power conditioning. Results are presented for the first such monolithic microwave integrated circuit (MMlC) amplifiers and four-cell amplifiers at X-band. Drain bias voltages up to 40 V with such amplifiers have been achieved.

10W ultra-broadband power amplifier

“…The unit-cell amplifier is a 2-stage MMIC PA that uses HIFET configuration [5][6][7]. The principle of this HIFET MMIC PA based on GaAs MESFET has been published in [8].…”

Ultra-Broadband GaAs HIFET MMIC PA

“…The optimum impedance Zopt of a HIFET consisting of N cells in series is zopt = N (Vds-Vknee)/1ds (2) The MMIC described in this paper is a 2-stage design with 4 FETs in series each for the driver and power stage. The FET cell in the driver stage and power stage are 2mm and 3.6mm respectively.…”

“…Therefore these devices have to be operated at relatively low voltages (< IOV). Consequently, in many applications requiring high voltages, designers try to increase the voltage bias of microwave circuits by connecting several devices DC in series but RF in parallel [1][2]. While connecting devices DC in series helps in biasing at higher voltages, the RF impedance of the RF parallel combination becomes very low, leading to difficulties in matching for broadband applications.…”