Grid amplifiers

Author: Kim, Moonil

Year: 1993

Degree: Dissertation (Ph.D.)

Advisor: Rutledge, David B.

Committee Member: Unknown, Unknown

Option: Electrical Engineering

DOI: 10.7907/19xw-he51

Abstract

Presented in this thesis are two grid amplifiers for operation in the microwave range. The first 5 x 5 MESFET amplifier grid verified the design approach by showing a gain of 11 dB at 3.3GHz. The second 10 x 10 amplifier grid, which has a metal layout pattern suitable for future monolithic integration, has shown a gain of 10 dB at 10 GHz with a 3 dB bandwidth of 1 GHz. The active devices in the grid were custom-designed HBT differential-pairs with a self-biasing resistor network for the base. This amplifier grid has produced a saturated output power of 450 mW while exhibiting a noise figure of 6.5 dB. The amplifier grid was also converted into an oscillator with smooth frequency-tuning between 8 and 11 GHz by using external feedback. A grid-array system of an oscillator and the amplifier was built to show the conservation of propagation angle for an rf beam through the amplifier grid. Amplitude modulation of the grid amplifier gain was demonstrated by applying a modulating signal to the grid's dc bias lines.

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