Title: Advanced W-Band Gallium Nitride (GaN) Monolithic Microwave Integrated Circuits (MMICs) For Cloud Doppler Radar
Presenting Author: Andy Fung
Organization: Jet Propulsion Laboratory

Abstract:
The Decadal Survey for Earth Science has recommended a multi-frequency Doppler radar capable of achieving more and higher quality data acquisition. Multi-frequency band Doppler radar, including W-band, particularly at the 94 GHz atmospheric window is of interest to detect and characterize the nature of clouds and other atmospheric constituents. Due to fast dynamic processes occurring in a large volume of atmosphere and the limited observation time from the high traverse rate of the science instrument over the field of view, radar arrays are crucial for increasing measurement rates of atmospheric phenomena in 3D. This will provide more data for modeling to best support the goal of improving the prediction of the behavior of atmospheric phenomena. Array remote sensing instruments will enable greater spatial observation with higher science data retrieval rates. A key technology for implementing arrays is monolithic microwave integrated circuits (MMICs). MMICs are ideal for implementing arrays due to their economical production cost and small form factor. We will present our effort on developing new W-Band (75-110 GHz) Gallium Nitride (GaN) MMIC power amplifiers and low noise amplifiers for cloud Doppler radar in support of the Aerosol/Cloud/Ecosystem Mission and other future concepts under the 2010 Advanced Component Technology program. GaN has the highest intrinsic voltage breakdown field of any currently available semiconductor material from which transistors can be produced that are capable of functioning in W-band. This property enables GaN to be the highest RF output power density semiconductor amplifier technology for sourcing the most output power per unit gate width in W-band. Higher power density supports higher efficiency as less inherently lossy power combining is needed to produce the net required system output power from the amplifiers. This ultimately leads to a physically smaller radar transmitter array with fewer parts that are less expensive to construct and more energy efficient to operate.