GaN MMIC Ka-Band Power Amplifier

NASA is seeking innovative Advanced RF Platform technologies at the physical level, specifically Ka-Band high efficiency high linearity 10 to 20 Watt solid state power amplifiers (SSPAs), to meet the needs of future space missions for communications and sensor applications. Space missions require small size, weight, and power (SWaP) among the hardware components. As a result, monolithic microwave integrated circuits (MMICs) are well suited to fill this need. In Phase I of this SBIR, Custom MMIC Design Services, Inc. (Custom MMIC) analyzed a number of commercially available Gallium Nitride (GaN) MMIC process technologies from domestic foundries based in the United States, and selected the optimum process for linear power amplifiers (PAs) -the 0.2 um GaNprocess as offered by Northrop Grumman Space and Technology (NGST). Custom MMIC’s use of novel small- and large-signal linear power amplifier (PA) circuit design techniques led to circuit simulationsexhibiting a large signal gain greater than 22 dB from 31.7 to 32.3 GHz, a linear output power of 13 W, input and output return losses of better than -20 dB, a PAE of 41% PAE, and an error vector magnitude (EVM) of 4.5% for 8PSK 500 MHz modulation. In addition, Custom MMIC’s use of the balanced amplifier topology allowed the simultaneous independent optimization of input/output return losses and internal PA impedances for linearity and PAE. As a result, Custom MMIC has produced a design that represents a new industry state-of-the-art benchmark for linear Ka-Band GaN MMIC PAs. In Phase II, we will develop not only the MMIC hardware that represents this design for JPL at Ka-Band (31.8 - 32.3 GHz) but also a similar linear PA for GSFC at K-Band(25.5 - 27 GHz) and a saturated radar PA for JPL at 35 GHz.