High Power Broadband Amplifiers for 1-18 GHz Naval Radar
Abstract
Three generations of dual-gate AlGaN/GaN HEMTs on sapphire were fabricated and characterized. First generation dual-gate HEMT had equal gate lengths of 650 nm produced through stepper lithography. Current gain cut-off frequency (f sub tau)) of 20 GHz, 60 V breakdown, 11 dB small-signal gain, 2.5 W/mm saturated output power, and 35% power added efficiency (PAE) at 4 GHz were achieved. Second and third generation dual-gate HEMT had unequal gate lengths to simultaneously achieve both large f(sub tau) and breakdown voltage. Gate one located closest to the source had a gate length of 150 nm and gate two had a gate length of 300 nm. Both gates had 'Upsilon' shaped cross-sections to reduce gate resistance and were defined by e-beam lithography. An f(sub tau) of 52 GHz and breakdown voltage greater than 100 V was achieved for second generation dual-gate devices. Single gate devices with gate lengths of 150 nm fabricated on the same sample showed a breakdown voltage of 40 V. With an improvement in both gate lithography and material, third generation dual-gate devices produced an f(sub tau) of 65 GHz, breakdown voltage of 70 V, 12 dB small-signal gain, 3.5 W/mm saturated output power, and 45% PAE at 8.2 GHz.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 2002
- Accession Number
- ADA403109
Entities
People
- Mark J. W. Rodwell
- Umesh Mishra
Organizations
- University of California, Santa Cruz