Title :
Stability design for grid amplifiers
Author_Institution :
Dept. of Electr. Eng., California Inst. of Technol., Pasadena, CA, USA
Abstract :
At Caltech we have been developing grid amplifiers for large-scale power combining of solid-state devices. In a grid amplifier, both the splitting and combining are done in free space. In this presentation, we consider the stability design for two recent grids: a 670-mW millimeter-wave HBT 36-element grid amplifier demonstrated by Cheh-Ming Liu at Caltech, and Emilio Sovero at Rockwell and a 3.7-W X-band pHEMT 100-element grid demonstrated by Michael DeLisio at Caltech, and Scott Duncan at Lockheed-Martin. In grid amplifiers, the elements are closely spaced, at intervals between λ/10 and λ/3. The close spacing raises serious issues about the stability of the grid, and we discuss the stability models that we use, and the procedure for stabilizing grids. For grids, the gain measurements have been done in free space, and we discuss ideas for calibration
Keywords :
HEMT circuits; calibration; frequency stability; heterojunction bipolar transistors; microwave amplifiers; millimetre wave amplifiers; power combiners; 3.7 W; 670 mW; X-band; calibration; gain measurements; grid amplifiers; large-scale power combining; millimeter-wave HBT amplifier; pHEMT amplifier; stability models; Degradation; Frequency; HEMTs; Heterojunction bipolar transistors; Large-scale systems; PHEMTs; Polarization; Power amplifiers; Solid state circuits; Stability;
Conference_Titel :
Millimeter Waves, 1997 Topical Symposium on
Conference_Location :
Kanagawa
Print_ISBN :
0-7803-3887-1
DOI :
10.1109/TSMW.1997.702488
