Susanta Kumar

Resent developments in wireless communication systems demand good Band pass filter (BPF) to select the required signal from the adjacent unwanted signals. In this paper one parallel coupled 3rd order Band pass filter with centre frequency 5GHz and 15 % Fractional Bandwidth (FBW) has been designed with the conventional Microstrip transmission line. This designed BPF has been simulated with the help of MoM based IE3D EM simulation software and the corresponding equivalent lumped L-C circuit model has been extracted. The simulated results provide a good agreement with the circuit model results. Here it is found that the proposed parallel coupled BPF provides unwanted harmonics at 9.6GHz and 13.5GHz. Therefore, in this paper attention also has been given towards the suppression of those harmonics with the help of Defected Microstrip Structures (DMS) in addition with the proposed parallel coupled microstrip BPF. Finally, the proposed BPF filter has been fabricated and measured with an Agilent make vector network analyzer of model N5230A and good agreement between simulated and measurement results have been obtained