The Aerosol/Cloud/Ecosystem (ACE) Decadal Survey Mission, and the Cloud and Precipitation Processes Mission (CaPPM) can benefit from new 94 GHz array scanning radar capability. New W-band GaN amplifiers that have been development under ESTO ACT can enable the most compact electronically steerable transceiver arrays for cloud Doppler radar, which can significantly increase new science data retrieval rates. InW-band (75-110 GHz) GaN amplifiers are presently the highest RF output power density (>1 Watt per MMIC) with high efficiency (~20%) semiconductor technology available. We have designed, fabricated and now characterizing new GaN PAs, driver amplifiers and low noise amplifiers for the 3-band Doppler radar instrument concept (Sadowy IIP13) targeting ACE and CaPPM requirements. Future developments in GaN amplifiers will enable higher frequency radar arrays capable of characterizing even smaller particles beyond 110 GHz.