Compact multilayer dual-band filter using slot coupled stepped-impedance-resonators structure

In this article, a new miniaturized configuration of single‐input‐single‐output dual‐band bandpass filter operating at ISM 2.45 GHz and UNII 5.8 GHz frequency bands using a multilayer structure with stepped‐impedance resonators is presented. A coupling aperture is introduced in a common ground to ensure the coupling between the two resonators located in the upper layer and the lower one. The use of stepped‐impedance resonators allows tuning the two bands at desired frequencies. Finally, a design prototype was fabricated to validate the proposed concept. The insertion loss and return loss at the central frequency are −1.35 dB and −17 dB for 2.45 GHz band, and −0.98 dB and −13 dB for the 5.8 GHz band, respectively. There is a good agreement between experimental and full‐wave electromagnetic simulation results. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1635–1638, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24417