The AFM04P2-000 is a high performance power GaAs MESFET chip having a gate length of 0.25 m and a total gate periphery of 400 m. The device has excellent gain and power performance through 40 GHz, making it suitable for a wide range of commercial and military applications in oscillator and amplifier circuits. It employs Ti/Pd/Au gate metallization and surface passivation to ensure a rugged, reliable part. Throughsubstrate via holes are incorporated into the chip to facilitate low inductance grounding of the source for improved high frequency and high gain performance.