Monolithic Integration of Microwave GaAs Power FETs.
Abstract
Monolithic integration of GaAs power field effect transistors (FETs) at X-band microwave frequencies is investigated. Incorporation of on-the-chip matching using lumped elements and coplanar ground metallization is investigated for monolithic FET device design. Coplanar microstrip transmission lines fabricated on alumina substrates are used to interface with the GaAs chips. Microstrip to coplanar microstrip transitions are also incorporated on the alumina substrate. To demonstrate the monolithic approach to microwave power amplification, a single-stage and two-stage push-pull amplifier were designed and fabricated. The two-stage design employs four transistors, a pair of 600 micron gate width devices for the first stage and a pair of 1.2 mm gate width devices for the second stage, monolithically integrated on a 2 mm x 2 mm GaAs chip. The single stage monolithic push-pull amplifier is just 1/2 of the two-stage chip. To provide the necessary 180 deg out of phase signals for the push-pull devices, 180 deg hybrid rings fabricated on alumina substrates are used. The single stage push-pull amplifier exhibits a small signal gain of 8 dB at 9.5 GHz with a 10% 1 dB fractional bandwidth. This amplifier yields 760 mW with 4.7 dB gain, also at 9.5 GHz with 21% power-added efficiency. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1978
- Accession Number
- ADA062294
Entities
People
- D. W. Shaw
- R. E. Williams
- V. N. Sokolov
Organizations
- Texas Instruments