Broad-Band Microwave Measurements on GaAs "Traveling-Wave" Transistors

Instantaneous gain, noise figure, reverse attenuation, and gain and phase control measurements in the frequency range 8-18 GHz have been performed on GaAs traveling-wave transistors. The broad-band high-gain nature of the device together with the requirement for several bias connections precluded the use of standard test fixtures, and resulted in a package design exhibiting less than 1-dB insertion loss over the band together with 75- to 90-dB internal isolation. Untuned X-band gain, noise figure, and reverse attenuation were 12 dB, 18 dB, and 32 dB, respectively, and the gain and phase could be electronically varied over a 35-dB and 360° range. When RF tuning was employed, the gain, on the average, improved by 10 dB.