Novel defected ground structure element with triple transmission zeros and its application for multispurious suppression of microstrip parallel-coupled-line bandpass filter

A novel compact defected ground structure (DGS) element with triple transmission zeros is proposed. The zeros can be tuned individually by the DGS geometry and the overall etched area is kept as compact as that of the conventional structure with single zero. The traditional microstrip parallel‐coupled‐line bandpass filter cascading this new element, not only achieves the multispurious suppression but also its basic design formulation is retained. A prototype DGS filter was designed and tested to validate its performance. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1409–1412, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22457