Design, Simulation and Manufacturing Microstrip Low-pass Filter by Wide Stopband and Changing Fast Situation from Passing State to Stopping

ABSTRACTIn this paper, a new microstrip low-pass filter will be presented for achieving high ability to choose wide stopband and suitable operation. This filter is built after design and simulation, and results of measurement will confirm the design accuracy. The results show that the overall performance of the recommended structure is improved in terms of physical dimensions, sharpness of response, and width of stopband, compared to old structures. Cut-off frequency of filter is 1.1 GHz. The stopband is so wide, and the amount of weakness in this band is equal to −20 dB. Roll-off rate parameter of the proposed filter is equal to 240 dB/GHz. This means that changing filter condition moves rapidly from passing to stop state. Size of proposed filter is small and equal to 27 mm × 16 mm. Results of simulation and measurement of the fabricated sample exhibit the same reaction.