Dual Wide Band, Compact, Planar Band-Stop Filter with Better Selectivity

A novel compact broad-band microstrip band stop filter with dual frequency response is proposed in this communication. The structure consists of two parallel coupled lines pairs with one pair open ended behaving as a resonator to give the desired pattern at two different frequency bands. The structure is developed at C and K band of frequencies and can be scaled for other frequencies accordingly. The 3-dB bandwidths achieved at the lower and upper band are 120% and 22% respectively. Good agreement between the theory and the simulation has been achieved. Further selectivity improvement concept has been implemented by introducing DR puck resonator at one end.