A novel compact dual-band micro-strip band-pass filter design

A compact dual-band BPF is proposed and designed with novel stepped-impedance resonance to operate at 2.4GHz and 5.2GHz. The modified "S" form half-wavelength stepped-impedance resonance is constructed to excite the dual resonances at the two specified frequencies with miniaturized overall size simultaneously. It saves more than half the circuit size compared with the general dual-band topology. The DGS hybrid structures are used to make the filter's bandwidths fitness the need of WLAN communication. The simulation and measurement results show the dual-band feature exhibiting the good dual-band filtering performances of two pass-bands at 2.4GHz and 5.2GHz, and rejection-band return losses higher than 30dB.