A method for predicting the Fowler-Nordheim parameters A and B, and the capacitance for a unit cell of a gated field emission array is developed, applied, and integrated into end-to-end rf amplifier design. Density modulated rf amplifiers require a high frequency, well characterized electron emission source for efficient operation; a cathode constructed of field emission arrays is a potential candidate for insertion into the next generation of twystode and klystrode amplifiers. The A, B, and C parameterization of the emission from model unit cell geometries is done by a boundary element technique. The behavior of A, B, and C with variation in device material and geometry is illustrated with two sample case sets. Finally, the utility of A, B, and C in predicting rf device performance requirements is illustrated.