Noise figure limitations and input match conditions of the lattice mixers

The intrinsic noise analysis of the lattice mixers, based an the nonlinear microwave circuit theory, is presented. Eight different mixers, which are Z-, Y-, H-, and G-types of circuit with either open- or short-circuited image terminations are combined under an unified framework for computer-aided analysis and optimization. The optimization variables are (i) the RF termination, (ii) the LO power which controls the mixer circuits parameters (iii) and the circuit type. In the computer simulation, the diode series resistance r/sub s/ is also taken as a parameter. Optimum noise RF termination is also obtained analytically in terms of generalized parameters, and it is shown to be different from the optimum loss RF terminations. Finally the eight different types of lattice mixer circuits are simulated by a computer with respect to the two different optimization criteria and ordered with respect to their figures of merit.