In recent years, the CMRC filter has been an attractive candidate for use in mixer and frequency multiplier circuits to improve the performance due to its low-insertion loss, sharp rejection, shorter size and wider stop-band. However, complex structures, too much variables and inefficient design method hindered its widespread use. In this study, we report on the application of the implicit space mapping algorithm in design of CMRC filter to greatly improve the design efficiency. Finally, a mixer with CMRC filter is designed and fabricated based on Rogers substrate process. The measured performance of this mixer is sufficient for engineering applications.