Our recent research has shown that the main technical difficulties employing field emission arrays (FEAs) in electron guns of microwave power amplifiers could be attributed to the FEAs' insufficient emission current density, emission stability, and the defocusing of the electron beams. The investigation of these parameters and measures for performance improvement are described in this paper. The conditions for obtaining a current density of several A/cm(2) and a stable working point are studied and realized. An electron gun with the FEAs for traveling wave tubes (TWTs) was designed and simulated, which allows focusing of a 100 mA electron beam with a 30degrees divergence angle. (C) 2003 Elsevier Science B.V. All rights reserved.