Patent ID: 7855624

Claim:
A field emission structure, comprising: a first plurality of field emission sources oriented in a positive polarity direction; and a second plurality of field emission sources oriented in a negative polarity direction, said first plurality of field emission sources and said second plurality of field emission sources having field emission strengths, polarities, and positions in accordance with a desired spatial force function, wherein a first combined field emission strength of said first plurality of field emission sources is substantially equal to a second combined field emission strength of said second plurality of field emission sources, wherein said first plurality of field emission sources and said second plurality of field emission sources include a biasing field emission source, wherein said field emission sources of said first plurality of field emission sources and said second plurality of field emission sources other than said biasing field emission source have polarities and positions in accordance with a code, wherein said code comprises at least one of a Barker code, a Gold code, a Kasami sequence, a hyperbolic congruential code, a quadratic congruential code, a linear congruential code, a pseudorandom code, or a chaotic code.