NEW NON-LINEAR APPROACH FOR THE EVALUATION OF THE LINEARITY OF HIGH GAIN HARMONIC SELF OSCILLATING MIXERS

In this work, the linearity of a high gain Harmonic Self Oscillating Mixer (HSOM) is analyzed. In order to obtain high conversion gain, the working point of the HSOM is established close to a Hopf bifurcation point. The traditional figures of merit used to characterize the linearity of conventional mixers cannot be directly applied to characterize the behavior of autonomous circuits, because of the influence of the input RF signal power on the autonomous signal parameters. The 1\,dB compression point and the third order distortion will be analyzed as a function of the harmonic content and maximum gain of the circuit. From the collected data, the optimum harmonic content and the maximum conversion gain of the HSOM can be selected, for a particular application, in order to minimize the output IF signal distortion.