Design and Analysis of a 60 GHz Narrowband Band-pass Filter Based on Defected Coaxial Bragg Waveguide

Based on the pass-band characters of defected coaxial Bragg waveguides, a novel topology of narrow-band, band-pass millimeter-wave filter at 60 GHz is designed and analyzed by making use of the multi-wave interaction formulation as well as software Ansoft HFSS. It is found that, if a defected Bragg filter with a large transverse dimensional size operates at high frequency, the spurious coupling between the operating mode and the competing modes will spoil the pass-band structure; but fortunately, this negative effect can be suppressed by applying Hamming-window-function distribution to the ripples amplitude of the filter. Results show the filter has a narrow fractional bandwidth less than 0.1% with a low insertion loss below 1.5 dB and large dimensional size, which favors to select the specified narrow-band signal in high power applications.