Noise spectrum of a diode with a retarding field

Abstract

A general expression for the noise-power spectrum generated by t he random emission of electrons of arbitrary trajectori es within a wavegu ide is obtained. A n ume rical solut ion of t he potential distribution within a plane d iode is effected , and a famil y of curves from wh ich the potential di stribu t ion may be obtained is graphed. A graphical co mparison bet ween several actual potential distribution s and Von Laue's solu tion is gi,·en. The above resul ts are u t ili zed to derive t he equ ivalent mean-square fl uctuation current du e to the space charge w ith in a diode for two cases of potential d istribution, namely, t he linear di s tribution, and t hat di stribu tion which occur at the neighborhood of the beginning of the retarding field. For t he case of t he li near potent ial distribution, the equivalent no ise temperatu re of the diode con ductance is sho\\'l1 to be eq ual to th e cathode tempe ratu re.