In the effort to develop a high performance field emission cathode for application in microwave amplifiers, it is clear that the emitter structure should have a sharp emitter surface, a large emitter height, a small. gate opening size, and a small emitter angle. We have developed a technique that fabricates knife-edge field emission arrays (KEFEA) on (110) silicon wafers. KEFEA has an optimized structure meeting the requirements mentioned above. The emitter edge radius is about 250 angstrom or less, the emitter height is 8 mum, and the gate gap is approximately 0.2 mum. Experiments have exhibited Fowler-Nordheim type field emission with gate-to-substrate bias voltage less than 50 V.