| MMIC DHBT Common-Base Amplifier for 172 GHz |
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| NASA’s Jet Propulsion Laboratory, Pasadena, California | |
| Feb 01 2006 | |
This single-transistor circuit performs comparably to a prior four-transistor circuit.
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Figure 1 shows a single-stage monolithic microwave integrated circuit (MMIC) power amplifier in which the gain element is a double-heterojunction bipolar transistor (DHBT) connected in common-base configuration. This amplifier, which has been demonstrated to function well at a frequency of 172 GHz, is part of a continuing effort to develop compact, efficient amplifiers for scientific instrumentation, wide-band communication systems, and radar systems that will operate at frequencies up to and beyond 180 GHz. The transistor is fabricated from a layered structure formed by molecularbeam epitaxy in the InP/lnGaAs material system. A highly doped InGaAs base layer and a collector layer are fabricated from the layered structure in a triple mesa process. The transistor includes two separate emitter fingers, each having dimensions of 0.8 by 12 µm. The common-base configuration was chosen for its high maximum stable gain in the frequency band of interest. The input-matching network is designed for high bandwidth. The output of the transistor is matched to a load line for maximum saturated output power under large-signal conditions, rather than being matched for maximum gain under small-signal conditions.  Figure 1. This Common-Base, Single-Transistor Amplifier is designed to provide useful power gain in the frequency band of 170 to 180 GHz.  Figure 2. These Gain and Output-Power Curves were derived from measurements on the amplifier of Figure 1 at a frequency of 172 GHz. This work was done by Vamsi Paidi, Zack Griffith, Yun Wei, Mattias Dahlstrom, Miguel Urteaga, and Mark Rodwell of the University of California at Santa Barbara and Lorene Samoska, King Man Fung, and Erich Schlecht of Caltech for NASA’s Jet Propulsion Laboratory. For further information, access the Technical Support Package (TSP) free on-line at www.techbriefs.com/tsp under the Semiconductors & ICs category. In accordance with Public Law 96-517, the contractor has elected to retain title to this invention. Inquiries concerning rights for its commercial use should be addressed to: Innovative Technology Assets Management Refer to NPO-40956, volume and number of this NASA Tech Briefs issue, and the page number. This Brief includes a Technical Support Package (TSP).
MMIC DHBT Common-Base Amplifier for 172 GHz (reference NPO-40956) is currently available for download from the TSP library. Login first to download.
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