A three-stage monolithic microwave integrated circuit (MMIC) W-band amplifier has been constructed and tested in a continuing effort to develop amplifiers as well as oscillators, frequency multipliers, and mixers capable of operating over wide frequency bands that extend above 100 GHz. There are numerous potential uses for MMICs like these in scientific instruments, radar systems, communication systems, and test equipment operating in this frequency range. This amplifier can be characterized, in part, as a lower-frequency, narrower band, higher-gain version of the one described in “Power Amplifier With 9 to 13 dB of Gain from 65 to 146 GHz” (NPO-20880), NASA Tech Briefs, Vol. 25, No. 1 (January 2001), page 44. This amplifier includes four InP high-electron-mobility transistors (HEMTs), each having a gate periphery of 148 µm. In the third amplifier stage, two of the HEMTs are combined in parallel to maximize the output power. The amplifier draws a current of 250 mA at a supply potential of 2.5 V.
In a test, this amplifier was driven by a backward-wave oscillator set to provide an input power of 2 mW. The output power of the amplifier was measured by a power meter equipped with a WR-10 waveguide sensor. As shown in the figure, the amplifier put out a power between 40 and 50 mW over the frequency range of 75 to 110 GHz, which is the entire frequency band of the WR-10 waveguide. At the stated power levels, this amplifier offers a power-added efficiency of slightly more than 6 percent.
This work was done by Lorene Samoska of Caltech for NASA’s Jet Propulsion Laboratory.For further information, access the Technical Support Package (TSP) free online at www.techbriefs.com/tsp under the Semiconductors & ICs category. NPO-30577
This Brief includes a Technical Support Package (TSP).
MMIC Power Amplifier Puts Out =40 mW From 75 To 110 GHz
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Overview
The document is a technical support package from NASA, specifically referencing NPO-30577, which details advancements in Monolithic Millimeter-wave Integrated Circuit (MMIC) technology. It highlights a power amplifier capable of delivering an output of ≥40 mW across a frequency range of 75 to 110 GHz. This development is part of NASA's Commercial Technology Program, aimed at making aerospace-related technological advancements accessible for broader scientific, technological, and commercial applications.
The document includes various sections, with Page 9 featuring a power amplifier chip operating in the 140-170 GHz range, showcasing its S-parameters and output power as a function of frequency. The graphs illustrate the gain and return loss characteristics, indicating the performance of the amplifier at different frequencies.
Page 7 discusses an active doubler designed using a harmonic balance simulator, which employs grounded coplanar waveguide (CPW) lines for matching elements. It describes a class B doubler that suppresses the fundamental frequency using a quarter-wave open stub, allowing for efficient conversion to the second harmonic. The highest frequency reported for a HEMT doubler is 180 GHz, with a conversion loss of 6 dB at an input power of 0 dBm, while a 94 GHz Schottky diode doubler achieved similar performance metrics.
The document also includes acknowledgments on Page 10, recognizing the funding from DARPA and contributions from various individuals and institutions, including the Jet Propulsion Laboratory and Caltech. This section emphasizes the collaborative nature of the research and the technical expertise involved in the project.
Overall, the document serves as a comprehensive overview of the advancements in MMIC technology, particularly in power amplification and frequency doubling, showcasing NASA's commitment to innovation in aerospace technology. It also provides contact information for further inquiries and access to additional resources through the NASA Scientific and Technical Information Program Office, emphasizing the importance of sharing knowledge and fostering partnerships in technological development.
