Miniaturization of dual-mode resonators by fractal iteration for suppression of second harmonic

We present a miniaturization technique for square dual‐mode resonators. By using the Minkowski fractal iteration it is possible to obtain compact resonators. Furthermore, the second harmonic is highly attenuated, thus enhancing the rejection in the upper band. A fourth order filter using two dual‐mode fractal resonators has been fabricated to illustrate these results. We use the suspended substrate technology to design these resonators, but the results can be extended to other technologies. © 2006 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2007.