Optimization of Broadband Bandpass Filter Using Tapered Electromagnetic Bandgap Structures

In this paper, a new technique for the design of broadband bandpass filter with large stopband is proposed. The proposed filter structure combines filter designed by a traditional analytical approach and two tapered electromagnetic bandgap structures. Chebyshev distribution is adopted to eliminate ripples in the passband caused by the periodicity of the EBG structure. Both the simulation and measurement results of a design example show that the designed filter has small in-band insertion loss and large out-of-band attenuation throughout a very broad stopband. The proposed filter structure has good frequency scalability and controllability.