Single 3-V supply operation GaAs linear power MESFET amplifier for 5.8-GHzISM band applications

A GaAs linear power amplifier operating with a single 3-V supply has been d eveloped for 5.8-GHz ISM band applications. Two kinds of refractory WNx/W s elf-aligned gate MESFETs, a P-pocket MESFET and an asymmetric MESFET with a buried p-layer (BP-MESFET) have been compared in terms of DC characteristi cs, small signal characteristics and power performances at 5.8 GHz. To obta in both high gain and high efficiency in the case of single 3-V supply oper ation at 5.8 GHz. we used a highly efficient and linear P-pocket MESFET for the output-stage pou-er FET and a high-gain asymmetric MESFET with a burie d p-laver (BP-MESFET) for the driver-stage FET. The bias condition for l-mm output-stage P-pocket MESFET was set near class-AB, so as to obtain suffic ient output power with high PAE. The two-stage power amplifier MMIC module which can include all matching and biasing circuits, has been designed and fabricated. The amplifier exhibits a high power gain of 17.9 dB and a high power-added efficiency of 25.7% with a sufficient output pou er of 18.7 dBm at the l-dB compression point. This self-aligned gate GaAs MESFET technolo gy is promising for near-future 5.8-GHz applications, because of such good power performance and good mass-producibility.