New ‘super’ low noise pHEMT devices

MicroWave Technology Inc (MwT) of Fremont, CA, USA, a subsidiary of IXYS Corporation, has introduced a family of three AlGaAs/InGaAs based low noise pHEMT devices with operational frequency up to 38 GHz.

MwT's new devices (MwT-LN240, MwT-LN300 and MwT-LN600) are fabricated using a high reliability AlGaAs/InGaAs pHEMT (pseudomorphic High Electron Mobility Transistor) process with a nominal 0.15 micron gate length and gate widths of 240 um, 300 um, and 600 um, respectively. These devices are equally effective for wideband (e.g. 6-18 GHz or 18-26 GHz) and narrow band applications up to 38 GHz, says the firm.

With minimum noise figure of 0.5 dB at 12 GHz with 2.5V drain bias, these devices are suited for commercial wireless and military applications requiring very low noise figure and high associated gain. Applications include: broadband military EW and defense communications, wireless communication infrastructures, point-to-point microwave radios, space/high rel, instrumentation and medical equipment.

The new devices are also available in surface mount packages, such as the MwT-71. Furthermore, the complete noise models such as "gamma opt" and noise parameters over frequency range are available for these devices to aid circuit design simulations. An application note on active bias circuitry for setting and stabilizing the gate bias is also available.

As an application support vehicle, MwT has developed 11 to 13 GHz hybrid modules using an MwT-LN240 (a 240 micrometer device) with a noise figure as low as 0.7 dB. A 6 to 18 GHz balanced amplifier module using a pair of MwT-LN240 devices has achieved noise figure between 1.5 and 1.7 dB across the band.

Freddy Vallenilla, EES SECC 2