The performance of an inplane lens field emission cathode, based upon a unit cell with a conical field emitter tip, gate, in-plane lens, and anode, are evaluated via MAGIC particle-in-cell simulation code. Electron emission is calculated from the Fowler-Nordheim equation. The trajectories and phase space were evaluated, the normalized beam emittance εn= 1.09×10-9m·rad and brightness Bn= 3.79×10-9A/(m·rad)2 for a typical in-plane lens Field Emission Cathodes.