Abstract: A novel coupling structure for designing dual-bandpass filters has been introduced in this paper.Chebyshev and quasi-elliptic 2.4GHz/5.2GHz dual-bandpass filter are designed by using microstrip SIR structure.The influence of structure parameters on filter coupling performance and transmission zeros is discussed by using 3-dimension finite element analysis models.This structure improves design freedom to fit easily the specific coupling coefficients at each band simultaneously,the locations of each pass band...