DC and microwave measurements on 0.7 μm single-gate (SG) and dual-gate (DG) In0.52Al0.48As/In0.53Ga0.47As planar doped two-dimensional electron gas field-effect transistors (TEGFETs) are reported. The DG devices show a large increase of the gm to gD ratios, which are as high as 100 at gm = 380mS/mm, compared with 12 at 420mS/mm for the single gate (SG) devices on the same chip, as well as 6dB improvement in the RF power gain compared with their SG counterparts.