A NOVEL DC-SOGHZ MMIC VARIABLE ATTENUATOR

Design, fabrication and performance of a newly developed novel DC-SOGHz MMIC variable attenuator with multi-function and low inserted phase shift are presented. This attenuator MMIC was fabricated by using Nanjing Electronic Devices Institute (NEDI) ion-implanted GaAs MMIC foundry process. Based on special designing of both the series MESFET and shunt MESFET control feeders, the MMIC has possessed the feature of excellent VSWR character even without the use of DC reference circuit, which is commonly adopted by various MMIC attenuators. Also, phase compensation technique was used in MMIC design to reduce inserted phase shift. On-wafer measurement results ol the developed MMIC chips in DC-SOGHz band are minimum attenuation C3.7dE maximum attenuation >38 * 5dB both inputloutput VSWRC 1.5 at minimum attenuation and (2.2 at marimum attenuation; low inserted phase shift attenuation ratio of < 1.2' /dB. The chip size is 2.33mm X 0.68mm X 0.lmm. To the best ofour knowledge, this is the fit reported MMIC voltage control variable attenuator with low inserted phase shift over DC-5OGHz in the world.