Improvement of the Generic Approach to Optimum Design of Microwave and Millimeter Wave Subharmonic Mixers

The design of subharmonic mixers is complicated and involves separation of signals and application of correct loading at idler frequencies. In this paper we propose an improvement to the novel generic approach, which was published by us earlier. The new method enables the designer to establish the optimum loading conditions for the different signals to achieve low conversion loss and good matching simultaneously. The main improvement compared to the "old" method is the ability to use the optimization option available in commercial microwave CAD to optimize the circuit performance, rather than using a manual tune option. Thus, the design can be fast and efficient. The method is demonstrated by a design example of a 60 GHz ×4 subharmonic mixer.