4~6GHz 6-bit MMIC Digital Attenuator With Low Phase Shift

This paper presents the 4~6GHz 6-bit MMIC digital attenuator with low phase shift. Phase compensation techniques were used in the MMIC design to reduce the phase shift. This attenuator is fabricated with 0.25µm GaAs PHEMT process. Simulation results of the developed MMIC chips in the 4~6GHz show that the 6-bit MMIC digital attenuator has 0.5dB resolution and 31.5dB dynamic attenuation range, input return losses was less than 15dB and output return losses was less than 17dB for all attenuation states, RMS is less than 0.4dB; insertion loss is less than 2.4dB; phase shift error is less than 3°for 35 attenuation states.