Ultra Wideband Band Pass Filter For Satellite Applications

In this paper, an ultra wideband band pass filter which is suitable for satellite applications is designed. The filter includes a defected ground structure (DGS) which is dumbbell shaped. DGS is the defect etched in the ground plane of the microstrip filter which results in increasing electrical length due to which size of the filter gets reduced. DGS also helps in harmonic suppression. The filter is designed and simulated by using CST Microwave Studio. Pass band of the filter is from 4 GHz to 8 GHz. The centre frequency of the filter is 6 GHz. The fractional bandwidth is 57%. The filter has S-21 of about -0.812 dB in the pass band and -30 dB in the stop band. It has S-11 less than 14 dB in the pass band. The equivalent circuit modeling of the filter is also found out. The filter is to be fabricated with FR4 as the substrate of thickness 0.8 mm and copper as the strip conductor. It is observed that the size of the proposed filter (33.7*7.4 mm(2)) is smaller than that of other conventional filters and the proposed filter has steeper and wider stop band.