Mechanism of rectification in vacuum-tube diodes at microwave frequencies

Expressions for the frequency variation of the rectification and the dependence on ratio of standing current to the saturation current are obtained which are valid for a cylindrical diode in a low-impedance circuit. Since, at h.f., the permittivity of the diode is a positive number of order unity the h.f. field penetrates to the cathode region and the dimension of major importance is the cathode-potential minimum spacing. Reasonable values of rectification can thus be obtained with big spacings.