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