Coplanar Waveguide Bandpass Filter with Controlled Transmission Zeros

A novel coplanar waveguide（CPW） dual mode bandpass filter with controlled transmission zeros is presented in this paper.A novel CPW resonator is utilized in this filter,which consists of a uniform impedance line and a couple of T-shaped stubs.By tuning the length of the T-shaped stub,the first two resonant modes of the resonator could be moved to form the passband.The location of the transmission zeros can also be adjusted by tuning the lengths of the T-shaped stubs and the out-of-band rejection level is enhanced.The simulated and measured results show that the bandpass filter has good performance,including low insertion loss,compact size,easy fabrication and the bandwidth and transmission zeros controllable.