Wideband microstrip bandpass filter based on intercoupled split-ring resonator.

A 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 [ABSTRACT FROM AUTHOR]