Wideband microstrip bandpass filter based on intercoupled split‐ring resonator

Abstract

AbstractA new design of wideband microwave bandpass filter based on intercoupled split‐ring resonator is proposed. The split‐ring resonator structure is well‐know for its unique resonance feature that exhibit a negative permeability. By implementing the split‐ring resonator directly on a microstrip transmission line, a bandpass filter with a large fractional bandwidth has been achieved. The novel periodic intercoupled split‐ring resonator bandpass filter is compatible with microwave planar technology and the passband region is controllable. The filter design has been validated and demonstrated in both simulations and experimental measurements. A bandpass filter with a fractional bandwidth of 50% at a center frequency of 14 GHz was achieved with a maximum insertion loss of 0.75 dB in the passband region. Meanwhile, the fractional bandwidth has been demonstrated to be controllable and this was reduced to 37% by sacrificing the periodicity of the intercoupled split‐ring resonator structure. Therefore, the flexible characteristics and the simple implementation method may render the proposed filter to be very useful in many frequency‐selective and oscillation‐suppression applications. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1809–1813, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22588