A Substrate integrated waveguide (SIW) wideband band pass filter with 150 degree bend is presented in this paper. Attenuation of higher transmission frequencies are achieved by using array of I-shaped periodic band gap structures at the collinear arms. Six I-shaped slots (three in each arm) are etched over the top conducting layer to achieve the purpose. Several major parameters of these I-shaped structures are studied and presented with detailed outcome. Insertion loss < 0.9dB over the entire pass band has been achieved by this technique. Moreover significant attenuation at the stop band frequencies ( 4GHz) is observed. The filter finds application in microwave X-band and Ku-band radar and satellite systems. © 2019 IEEE.