Microstrip bandpass filter with compact size for wireless communications

A microstrip bandpass filter (BPF) with compact size using a coupled transmission line is proposed. This filter operates at 2.79 GHz, that it is applicable in wireless communications. The filter is composed of the coupledtransmission line and T-shaped resonators (as main resonators). The proposed filter with fractional band width (FBW) of 1.64% has a narrow passband. Theupper stopband is extended up to 7.8 GHz (2.8fc) with better than 20 dB suppression level. The designed BPF presents a high return-loss (RL) in thepassband (18.87 dB). The overall dimensions of this structure is only 0.22λg × 0.11λg

Keywords:

microstrip , bandpass , T-shaped , stub