A novel compact dual-wideband bandpass filter

In this paper, a new novel compact dual-band bandpass filter is proposed. The module consists of two square defected structure in the ground and a dual-line coupling structure are used for coupling enhancement, the transmission zeros are then introduced to avoid being interfered by the WLAN radio signals by properly via holes. The proposed component is fabricated in a planar microstrip configuration and simulated by CST 2009. The dimensions of the module can be controlled within 20 mm × 19 mm, its two passbands can be arbitrarily positioned, which exhibits 40% 3-dB fractional bandwidth centred at 4.04 GHz and 34% 3-dB fractional bandwidth centred at 7.81 GHz, low insertion loss (0.1 dB at 4.01 GHz), a low group delay is less than 0.4 ns, and good stopband characteristics (|S21|<;- 55 dB at 2.2GHz, |S21|<;- 38.8 dB at 5.75GHz). We can see that it is the dual-band ultra-wideband(UWB) filter, which shows good frequency response. The proposed filter can be used in modern wireless communication systems.