CPW bandpass filters with controllable passbands

Defected coplanar waveguide (CPW) resonator has been analyzed, and multi-band bandpass filters with individually controllable passband have been developed. New dual-band and tri-band bandpass filters which center at 2.4/3.5/5.2 GHz have been designed, fabricated and measured. The measurements demonstrate the new presentations. The measured filter passband insertion losses are less than 2.7 dB. It has been noticed that the filter center frequencies can be individually controlled, and the bandwidths can be individually adjusted. Advantages of the new design are not only its simple and compact circuit topology, miniature circuit size, but also its less electromagnetic leakage.