Fundamental limitations of the Schottky mixer diodes in the lattice configurations

The intrinsic conversion loss of microwave Schottky-barrier mixer diodes in the lattice configuration is analyzed in the light of a more accurate diode model. For modelling purposes, conversion loss may be divided into intrinsic loss L₀ and parasitic loss L_p (2). Intrinsic loss is amount of loss that would occur if there was no parasitic elements, i.e. spreading resistance and nonlinear junction capacitance, in the diode. Thus, the intrinsic loss is caused by the finite junction conductance (it is not an ideal switch) and by nonoptimum terminations. Parasitic loss is defined as the increase in the conversion loss due to the presence of nonzero parasitic elements. The intrinsic loss sets a lower limit on the total conversion loss since it neglects losses due to the parasitic circuit elements. In this work, the effect of the spreading resistance r_s has been included for each driving level as a parameter too